Who We Are
About The Association
The Histiocytosis Association is the only organization of its kind, a global nonprofit organization dedicated to addressing the unique needs of patients and families dealing with the effects of histiocytic disorders, that connects patient and medical communities around the world with the resources needed along every step of the way, while leading the search for a cure.Our Vision
To one day see a world free of histiocytic disorders.
Our Mission
We are dedicated to raising awareness about histiocytic disorders, providing educational and emotional support, and funding research leading to better treatments and a cure.
Our Values
Leadership
Transparency
Charity
Community
Excellence
Message from our Team
The team at the Histiocytosis Association is excited about our future. The last five years have granted the opportunity to learn a lot about patience and perseverance, and we found out just how strong we truly are – as individuals, as a team, as a rare community, and as a world.
The Histiocytosis Association is about our community: each and every one of you. Our vision to see a world free of histiocytosis is what drives us every day. Our conversations with you, hearing about how these rare diseases have affected you, is why we show up to give our 110% every day. We hope that wherever you are, whatever you have faced, you know that we’re in your corner.
The Histiocytosis Association is prepared to continue to build upon its great legacy, working alongside our board members, stellar team, and community partners. We are committed to remaining focused on supporting our mission. This year, we hope you will join us at an event, take part in our online education series, and stay connected with us – not only through our online platform and social media, but also know that you can always call us to connect and share experiences. We care deeply about our community – about you – and you are the reason we work tirelessly to achieve our goals.
Association Team
Jen Silvers
Executive Director Read Bio Preview modal-Jen Silvers
Jen Silvers brings more than 20 years of nonprofit leadership to her work, with a passion for helping mission-driven organizations grow, streamline operations, and raise the resources they need to thrive. She’s led multi-million-dollar budgets, built fundraising programs from scratch, and helped teams do their best work by sharing clear goals, listening well, and staying grounded in purpose.
Most recently, Jen oversaw operations across multiple states for PACE Center for Girls, supporting dozens of sites and managing a $30M+ budget to help reach more youth in need. Before that, she served as Vice President of Development for Special Olympics Florida, boosting revenue and community engagement through creative campaigns and donor storytelling.
Her longest chapter was at the YMCA, where she spent nearly 18 years leading branches, developing teams, and fundraising for programs that change lives-work that still inspires her approach today. Long before her nonprofit career, Jen worked as a TV reporter and anchor, a background that shaped her love for honest communication and human storytelling.
Jen earned her MBA from the University of Lynchburg and holds a bachelor’s degree in Journalism from the University of Kansas. She is a Certified Fundraising Executive (CFRE) and believes that every mission deserves both heart and strategy.
Jen resides in Tampa, FL having been born and raised in the Washington, D.C. area. She and her boyfriend Jim love to play ice hockey, spend time with their two dogs, Finnegan and Bailey and enjoy the Florida sunshine at the beach!
Kristen Nesensohn
Chief Program & Development Officer Read Bio Preview modal-Kristen Nesensohn
Kristen Nesensohn has spent 20 years serving the community in a number of capacities – first as a development associate, then as a fundraising event manager and today the Chief Development and Program Officer. Like many that work in the non-profit sector, she is adept at wearing many hats and working in a variety of facets to support the mission of the Association – from education and awareness initiatives, to fundraising events and graphic design, she enjoys it all. But what she enjoys most is when she gets to work directly with the community from out behind her desk.
She had the privilege of working under our founder Jeff Toughill, then Deanna Fournier and now excited for Jen’s leadership.
Born and raised in Philadelphia, she now calls the Philly suburbs home. ‘You can take the girl out of Philly but you can’t take the Philly accent out of the girl – if you have ever spoken with her, you know it’s true. She doesn’t talk sports but she’ll always be rooting for the home team. She lives with her husband (a Mets and Bears fan), one daughter who is the light of her life and one very sweet yet rambunctious rescue dog, Millie. She says if she could live anywhere else it would be in a hill town in Italy.
Kristen once dreamed of being in the FBI but also thought she wanted to study art history. She graduated from Temple University with an American Studies degree. Her parents were always concerned about what she could possibly do with a degree in American Studies – today she proudly says she helps make a difference for the rare histio community.
She is proud to be a part of the Association’s efforts supporting patients and families and to witness the great strides and progress that have occurred in the last 25 years since she first joined the team. Her admiration for Jeff Toughill and his commitment to the community continues to inspire her every day.
Danielle Hellick
Chief Financial Officer Read Bio Preview modal-Danielle Hellick
Danielle Hellick serves as the Chief Financial Officer of the Histiocytosis Association. A long-time New Jersey resident, she lives just a short distance from the Association’s headquarters with her family.
When she’s not busy being a mom, Danielle enjoys family trips-especially to the beach-along with decorating and remodeling her home, reading the Bible, attending church, and listening to music. She also loves to laugh with others and is known for frequently referencing movie/tv show quotes with her Histio team.
With nearly two decades of experience in finance, Danielle found her career home at the Histiocytosis Association in 2018, where she is able to do what she loves while making a meaningful difference in the lives of others.
Kathy Wisniewski
Histiocyte Society Secretariat Read Bio Preview modal-Kathy Wisniewski
Kathy Wisniewski serves as the Secretariat for the Histiocyte Society as well as the HA’s Grant Program Administrator and host of the Beyond the Diagnosis Podcast. Prior to joining the Association in 2008 as the Volunteer Program Manager, she had already spent over 10 years in the nonprofit space, working in the Vocational Services Department of Goodwill Industries and then moving on to becoming the Volunteer Program Manager at a house museum, Stan Hywet, the former home of the co-founder of Goodyear Tire and Rubber.
Kathy is a Certified Health Coach and helps people find wellness in all aspects of life. She also has a passion for helping abuse survivors through her personal podcast, Tragically Beautiful. When she’s not working she enjoys hiking and chasing waterfalls, traveling, small towns and coffee shops.
Peter Yanefski
Communication and Operations Coordinator Read Bio Preview modal-Peter Yanefski
Peter Yanefski is the Communication and Operations Coordinator for the Histiocytosis Association and has been on the staff since May 2022. His hometown, like the Association, is Pitman, New Jersey, where he lives with his wife and 3 dogs. In his downtime, he likes binging TV (mostly Friends) and reading with his wife as well as playing with their dogs.
Peter became involved with the Association after previously creating online course videos in higher education. He is passionate about patient support, because he is a caregiver for his wife, who has a severe case of hydrocephalus that has in the past left her disabled for years at a time. He took that passion into non-profit patient advocacy, first at Blood Cancer United (then LLS) and now the Association.
Erica Dyer
Database/Compliance Coordinator Read Bio Preview modal-Erica Dyer
Erica Dyer is the Database/Compliance Coordinator for the Association. Originally from Queens, New York, Erica has lived in several places before settling in New Jersey, including Colorado Springs, Colorado. Outside of work, Erica enjoys cooking, watching cooking competition shows like Top Chef, and traveling with her family.
Erica began her non-profit career at Catholic Health Initiatives as a Prospect Researcher and Development Data Specialist. After losing her father to cancer while serving as his caregiver, she joined the Association, bringing a deep personal commitment to supporting patients and their families. That experience profoundly shaped her dedication to ensuring patient needs are understood, respected, and prioritized and continues to guide her work every day at the Association.
Melinda Atnip
Program and Outreach Coordinator Read Bio Preview modal-Melinda Atnip
Melinda Atnip has served as the Program and Outreach Coordinator for the Histiocytosis Association since January 2022, a role deeply shaped by her experience as a care partner. She lives in Southern California with her husband, and together they have two sons and a daughter-in-law. In their spare time, Melinda and her husband enjoy being with family and friends-making memories through travel, wellness activities, and sharing meals.
Melinda’s advocacy began in 2021 when her husband was diagnosed with Erdheim-Chester Disease (ECD), a rare blood cancer and histiocytic disorder. After months of medical uncertainty and navigating his diagnosis during the COVID-19 pandemic, she became determined to support others experiencing the same fear and isolation.
With a background in education, leadership, and outreach, Melinda leads the Histio Ambassador Program, recruiting, training, and supporting volunteers across the country who raise awareness, promote early diagnosis, and strengthen community connections.
Despite her husband’s chronic condition, he continues to lead an active life with the support of targeted therapy and his dedicated medical team. Melinda remains committed to bringing hope, education, and connection to patients and families so that no one facing a histiocytic disease feels alone.
Allegra McFadden
Fundraising/Patient Advocacy Coordinator Read Bio Preview modal-Allegra (Allie) McFadden
Allegra (Allie) McFadden is the Fundraising/Patient Advocacy Coordinator for the Association. She lives in Cypress, TX, with her husband, their three children, and several beloved pets. When she’s not working, Allie can usually be found on the sidelines of a softball field, basketball court, or at the swimming pool, cheering on her kids in their activities. In her spare time, she enjoys taking her children to the zoo, participating in Jeep club events, archery, and catching a good comedy show.
Allie became involved with the Association after her youngest child, Hudson, was diagnosed with RDD as an infant in 2019. She first joined as a volunteer fundraiser, then as an ambassador, and officially became part of the team in 2023 in her current role. Having personally experienced the fear and uncertainty of hearing the words “rare disease,” Allie is driven to support other families facing the same challenges. She understands how difficult it can be to find information, support, and knowledgeable physicians, and is passionate about helping others navigate their histio journey.
Board of Trustees
Tracy Brown
ChairwomanGovernance Committee ChairNoblis, Inc.
Reston, VA
Tracy Brown
Tracy Brown brings a passion for rare diseases, a people-first focus, and a problem-solving background to her role as a Board Trustee and the Chairwoman.
As Director of Law Enforcement Programs at Noblis, a non-profit science and engineering company, she is responsible for service delivery on multiple federal government programs in the law enforcement and intelligence domains.
In her more than 25 years of government contracting experience, she has worked with a variety of federal agencies in developing and deploying IT systems, conducting training, providing program management expertise, and delivering emerging technologies to support mission-critical government operations. She is a member of the Noblis Diversity, Equity, and Inclusion committee and participates in their corporate mentorship program as well.
Tracy’s Connection to Histio:
I am passionate about helping the histiocytosis community by ensuring funds raised are dedicated to research, family programs, and awareness. I began volunteering for the Histiocytosis Association in 2006 when my son, Ian, was diagnosed with Langerhans cell histiocytosis.
My husband Ryan, son Ian, and I have hosted Histio Hike Shenandoah since 2010.
I joined the Association Board in 2014 and previously served as Secretary, Succession Committee Chair, and currently serve as the Chairwoman of the Board and Governance Committee Chair.
Kelsey Cheek
Treasurer Digital Assurance & Transparency Senior ManagerPricewaterhouseCoopers, Philadelphia, PA Read Bio Preview modal-Kelsey Cheek
Kelsey Cheek graduated from West Chester University of Pennsylvania with two Bachelor of Science Degrees in Accounting and Finance. Upon graduation in 2015, she began her career with PricewaterhouseCoopers LLP (PwC) within their Trust Solutions group. She is currently Senior Manager of their Digital Assurance and Transparency group out of the Philadelphia office. Kelsey specializes in Enterprise Resource Planning (ERP) software transformations across various client industries, which include, Healthcare, Pharmaceuticals, Medical Device, Chemicals, Manufacturing, Retail, and Automotive.
Outside of PwC, Kelsey spends her time in a volunteer capacity coaching youth field hockey in New Jersey and Pennsylvania. She continues to support and facilitate various leadership programs for athletes from both her high school and college alma maters. Kelsey is most passionate about the work she has done to help develop these athletes into leaders and trail blazers within society. She is also an avid Philadelphia sports fan.
Kelsey is extremely excited to be considered for membership to the Board of Trustees. She looks forward with great passion and eagerness to help impact the lives of the histiocytosis community.
Eli Diamond, MD
TrusteeScientific Committee ChairMemorial Sloan Kettering
Cancer Center
New York, NY
Eli Diamond, MD
Dr. Eli Diamond is a neurologist and neuro-oncologist at Memorial Sloan Kettering Cancer Center. His training is in treating brain tumors and neurologic complications of cancer. He has been treating histiocytosis since he was in training in 2011 and this area is now his primary clinical and research focus.
Eli has conducted several research studies and clinical trials for adult patients with histiocytosis, including the trial that led to FDA approval of vemurafenib for BRAF-mutated Erdheim-Chester disease. He has implemented many other new treatments for patients with histiocytosis. Eli has lead several research studies about gene mutations in histiocytosis, as well as related to symptoms, quality of life, and caregiver needs.
Eli’s Commitment to the Histio Community:
I hope that my knowledge and passion for histiocytosis are an asset for the patient community in my participation as a Board of Trustees member and as the Chair of our Scientific Committee. In that role, I work with my colleagues to align our scientific and research priorities together with the needs, goals, and values of histiocytosis patients and families.
Jasmine Francis MD FACS
TrusteeAttending Surgeon of Ophthalmic OncologyMemorial Sloan Kettering Cancer Center
New York, NY
Jasmine Francis MD FACS
Dr. Jasmine Francis FACS is an Attending (Professor) Surgeon of Ophthalmic Oncology in the Department of Surgery at Memorial Sloan Kettering Cancer Center. She treats tumors inside and on the surface of the eyes, as well as those in the tissues around the eyes. One of her primary clinical and research focuses is ocular histiocytosis.
Jasmine has conducted a number of research studies on ocular histiocytosis including intraarterial chemosurgery as a treatment option for ocular (or neurological) histiocytosis, use utility of cell free DNA in ocular-involving histiocytosis, infiltration and expansion of the choroidal layer of the eye in histiocytosis, and understanding the spectrum of ocular disease in histiocytosis and gene-specific associations.
James Hassan, Esq
Trustee
Musick, Peeler & Garrett LLP
Los Angeles, CA
James Hassan
James Hassan, an adult histiocytosis patient, was diagnosed over 45 years ago after an agonizing eight-year process. He served as the Chairman of the Histiocytosis Association’s Board of Trustees until 2021.
Jim’s Connection to Histio:
Like many of you or your children, I have undergone chemotherapy, radiation, and a variety of experimental treatments. As a result, I believe I understand first-hand the anxiety and helplessness felt by patients and their families when facing this illness. I was introduced to the Association when I read an article written by Sally and Jeff Toughill (Founders of the Histiocytosis Association) chronicling their struggles in diagnosing and treating their daughter, Bethany. I identified with their situation and was very moved by their dedication to help other families. For several years, I worked as a volunteer, assisting with fundraising. When invited to join the Board of Trustees in 1998, I was excited to be involved first-hand with the tremendous efforts carried on by the Association staff and Board members. My personal objectives are to assist the Association in carrying out its ultimate goal of finding a cure for this disease, and supporting our patients and their families along the way.
Rima Jubran
TrusteeProfessor of Clinical PediatricsKeck School of Medicine of USC
Children’s Hospital Los Angeles
Los Angeles,CA
Rima Jubran
Dr. Rima Jubran is a Professor of Clinical Pediatrics at the Keck School of Medicine of USC practicing at Children’s Hospital Los Angeles in California.
One of her areas of clinical and research focus is histiocytic disorders of
childhood. She received her medical degree from Case Western Reserve
University School of Medicine, Cleveland, Ohio, master’s in public health
degree at George Washington University, Washington, D.C and master’s in academic medicine at the University of Southern California. Following her residency at Rainbow Babies and Children’s Hospital in Cleveland, she completed a fellowship in pediatric hematology/oncology at Children’s National Medical Center in Washington, D.C. . At CHLA, she also serves as the Director of Graduate Medical Education and oversees all physician training programs.
I am honored to be considered for membership to the Board of Trustees. I
have committed to improving the lives of children and adults with histiocytic
disorders throughout my career and this opportunity will allow me to further
contribute to the community in other meaningful ways.
Stephan Ladisch, MD
TrusteeMedical and Scientific Advisory Committee ChairChildren’s National Medical Center
Washington, DC
Stephan Ladisch, MD
Stephan Ladisch graduated from the University of Pennsylvania and completed his pediatric residency at Children’s Hospital of Boston. He first became interested in the histiocytoses during his fellowship in pediatric oncology at the National Cancer Institute, where he discovered an immunodeficiency syndrome associated with FEL (now known as a form of HLH). In 1978, he joined the faculty of the University of California, Los Angeles (UCLA), where he continued his research in histiocytosis and in cancer biology and has since been actively involved in developing histiocytosis clinical trials. He became Professor of Pediatrics in 1986, and in 1991, he was recruited to Children’s National Medical Center (CNMC) to direct and develop the new Center for Cancer and Transplantation Biology at the Children’s Research Institute (CRI). He has also served as CRI’s first Scientific Director (1998-2005) as Vice Chairman of the Department of Pediatrics, and is Program Director of the NICHD-funded Child Health Research Center at CNMC since 2000. He holds the Bosworth Chair in Cancer Biology and is Professor of Pediatrics, Biochemistry, and Molecular Biology at George Washington University (GWU).
Dr. Ladisch has an international reputation in pediatric oncology and in histiocytosis, and is the author of more than 150 peer-reviewed articles in the areas of histiocytosis, cancer biology and immunology, and pediatric oncology, and he is on the editorial board of several journals. He has trained numerous graduate students and postdoctoral fellows, many of whom have gone on to academic positions. He is a member of several academic societies, including the Society for Pediatric Research and the American Association for Cancer Research, and is a Fellow of the American Academy of Pediatrics. His training activities also include a major role in developing the multidisciplinary graduate student training program at GWU, where he served as Director of the Institute for Biomedical Sciences. He is a member of the National Institutes of Health College of Scientific Reviewers.
Dr. Ladisch’s laboratory focuses on membrane gangliosides, their synthesis and shedding, and their roles in cell signaling, tumor biology and immunology, as well as in some forms of childhood histiocytosis. His research has been funded by the National Institutes of Health since 1980. He is a founding member and past-president of the Histiocyte Society and former Chairman of the Board of Trustees and Scientific Committee of the Histiocytosis Association.
Dr. Ladisch currently serves as the Chairman of the Medical and Scientific Advisory Committee of the Histiocytosis Association.
Molly Zangrilli
TrusteeFamily PartnerChildren’s Hospital of Philadelphia
Philadelphia, PA
Molly Zangrilli
Molly Zangrilli joined the Histiocytosis Association as an Ambassador in 2025. Her daughter, Juliet, was diagnosed with primary HLH at age 14 and underwent a bone marrow transplant in 2024, inspiring Molly’s commitment to advocating for patients and families affected by histiocytic disorders and rare diseases. As an Ambassador, she has contributed to the HLH CME program, appeared on the Beyond the Diagnosis podcast, and presented at the Patient and Family Summit.
Molly serves as a Family Partner at the Children’s Hospital of Philadelphia, helping elevate the patient and family voice in care delivery. She also represents CHOP on the Pediatric Experience Collaborative, a network of pediatric hospitals focused on improving the experience of patients, families, and staff.
She advocates on Capitol Hill for rare disease policy priorities and is committed to increasing HLH awareness in the medical community.
Molly brings experience in public accounting, human capital consulting, and seven years as a small-business owner and International Board Certified Lactation Consultant. She holds a B.S. in Accounting from Penn State and lives in Paoli, Pennsylvania with her husband and three children.
Sydney Martin
TrusteeDonor Workup Specialist NMDP
Minneapolis, MN
Sydney Martin
Sydney Martin is an LCH survivor. She was diagnosed with LCH at the age of 10 years old. She had lesions in the orbit around her eye and upper spinal cord. The Giving Rocks Foundation originally started in 2007 as a passion project by 10-year-old Sydney Martin after a diagnosis of LCH has evolved into a successful 501(c)3 nonprofit. After researching LCH, Syd and her family were shocked to find that the potentially fatal blood disease was grossly underfunded with little research devoted to it. Sydney started selling her unique rock necklaces made from the shores of Lake Michigan to raise money for medical research, and Syd Rocks was born. Although she won her battle against LCH, Sydney was still passionate about finding a cure. The charitable business expanded to Giving Rocks Foundation, an organization with a powerful mission to eliminate all pediatric cancer, with a focus on LCH. Giving Rocks Foundation donates 100% of its proceeds to LCH research, with the belief that every rock can lead to a cure. Giving Rocks are sold on the HAA website today!
During her treatment for LCH, Sydney found a sense of belonging on the Oncology floor at Lurie Children’s Hospital in Chicago. She felt incredibly supported by her hospital peers, her medical team, and most of all by her Certified Child Life Specialist (CCLS). CCLS’s are health care professionals who help children and families navigate the process of illness, injury, disability, trauma, or hospitalization. Sydney’s experiences as a patient informed her decision to embark on a career in healthcare. Sydney received her Master of Science in Child Development from Erikson Institute and became a CCLS in 2021. She worked as CCLS on the General Pediatrics Unit at Rush University Medical Center from 2021-2023 providing comprehensive medical, social, and emotional support for patients and families. In June of 2023, Sydney began a new role as a Donor Workup Specialist at NMDP, formerly known as Be The Match. As a donor workup specialist, she helps healthy marrow and stem cell donors throughout the donation process. Additionally, she uses her healthcare background to educate donors on the donation process and shed light on the patient experience. She loves helping to facilitate lifesaving transplants and making sure donors feel proud of themselves for offering a lifesaving gift to a patient in need.
Sydney’s experience with LCH informed her career path and she is so excited to bring her experiences to the forefront as a Histio Ambassador!
Tim Morder
TrusteeSenior Vice President Sales & Marketing – Technical Solutions and ServicesLink Computer Corporation
Bellwood, PA
Tim Morder
Tim Morder resides in central Pennsylvania and brings more than four decades of distinguished
business and leadership experience to the Board. A graduate of Penn State University’s Smeal College of Business, Tim has built a career defined by strategic thinking, operational excellence, and a deep commitment to organizational stewardship.
Tim currently serves as Senior Vice President for a technology company, where he oversees budgeting, revenue generation, and cost control. His disciplined approach to financial management and his ability to guide complex operational functions have contributed significantly to the organization’s long‑term stability and growth.
Throughout his 50-year career, Tim has held management roles that reflect his natural leadership style and his dedication to developing strong teams. He shared that he is honored to join the Board and looks forward to contributing his skills and experience to the community. His insight and steady leadership will be valuable assets to the Board, as well as to the patients and caregivers the organization serves.
In addition to his professional accomplishments, Tim is a dedicated volunteer within the histiocytosis community. As a Histio Ambassador for several years, he has supported patients and families by sharing resources, offering guidance, and raising awareness of rare histiocytic disorders. Tim’s advocacy brings a compassionate, informed perspective to his service. Tim is also a 28-year member of Rotary International, a community- oriented group dedicated to helping others where he applied for and attained grants for the Histiocytosis Association. His commitment to helping others navigate their own journeys reflects both his character and his belief in the importance of community support.
Outside of his professional and volunteer commitments, Tim has been married to his wife, Karen, for 45 years. They have a daughter, Caitlin; a son, Michael; a daughter‑in‑law, Laura; and two grandsons who bring great joy to their lives. Tim and Karen also share their home with four Miniature American Shepherds, all of whom serve as therapy dogs and bring comfort and smiles to individuals in a variety of settings, including healthcare facilities. Tim enjoys spending time outdoors, especially walking and bicycling, and he and Karen are avid travelers. North Myrtle Beach, South Carolina, holds a special place in their hearts and has become their home away from home.
Chad Rubin
TrusteeStrategic Planning Committee ChairEndurance Advisors
New York, NY
Chad Rubin
Chad Rubin is a Managing partner at Endurance Advisors. Endurance is a strategic advisory firm that focuses on investor relations and capital markets. They help biopharmaceutical companies innovate. Chad has over 16 years of experience advising management teams in the sector. Prior to joining Endurance’s team in 2024, Chad was the managing advisor at Trout Capital.
He brings with him experience in advising life science companies on topics including company creation, seed funding, shareholder targeting, capital markets transactions, message crafting and scenario analysis. His experience includes work in finance, consulting and market analysis. He has been involved with companies from the pre-IPO stages to follow-on and convertible offerings. He is involved in capital transactions with corporate clients and has counseled clients on domestic and cross-border transactions and binary data events.
Chad holds a Bachelor of Arts degree in business administration with a concentration in finance from Franklin & Marshall College. He has a minor in film and media studies. He also holds Series 7, 79 and 63 securities licenses.
Chad’s Connection to Histio:
Chad began volunteering with the Histiocytosis Association in 2008 after his son, Jack, was diagnosed with Langerhans cell histiocytosis and secondary HLH. Jack and Chad’s wife, Kristy, lived at Children’s Hospital of Philadelphia for over 19 months fighting the diseases. Jack was cured with a bone marrow transplant and is a healthy boy today! Histiocytosis Association provided Chad with support, information and resources to help his family fight and beat the horrible disease. Chad and Kristy founded the annual fundraiser “All Jacked Up” in 2009. Together with friends and family they have raised over $500,000 to help find a cure.
Nicole Powell
TrusteeSenior Vice President, Business Development
Maxis AI
Edison, NJ
Nicole Powell
Nicole Powell, MBA brings nearly two decades of leadership in clinical research and over 20 years of advocacy in rare diseases to her role as a Board of Trustees for the HA. Her commitment to this mission is deeply personal-rare disease has directly
impacted her family, shaping her perspective and fueling her passion to support patients, caregivers, and the broader community navigating these challenges every day.
Through both her personal journey and professional career, Nicole has seen firsthand the resilience required of patients and the unwavering strength of caregivers. She understands the gaps that still exist-in awareness, access, and support-and is driven
to help close them. Her work has always centered on one core belief: that every patient deserves hope, visibility, and access to meaningful advancements in research.
With 19 years in clinical research, Nicole has dedicated her career to advancing innovation in clinical trials, with a focus on improving patient outcomes and accelerating access to life-changing therapies. She is known for building strong partnerships, leading with empathy, and championing patient-centered approaches that bring the needs of families to the forefront of research and development.
As a member of the HA Board of Trustees, Nicole is honored to further her mission to advocate for rare disease patients and caregivers, support continued research, and help ensure that no family feels alone in their journey.
Nicole holds a BA from the University of Texas at San Antonio and an MBA from Baylor University. She resides in Virginia with her husband and two sons, who continue to inspire her commitment to this work every day.
Kimo Stine, MD
Secretary
University of Arkansas for
Medical Sciences
Little Rock, AR
Kimo Stine, MD
Dr. Kimo Stine is a Professor of Pediatrics at the University of Arkansas for Medical Sciences practicing at Arkansas Children’s Hospital in Little Rock, Arkansas. Kimo has provided clinical care to children with histiocytic disorders, publish on their treatment options, and been a part of an international clinical trial to improve the outcome of children with LCH.
He attended medical school at the University of Kansas in Kansas City, KS, where he also completed his Pediatric Residency. He did a fellowship in Pediatric Hematology Oncology at Duke University and spent 2 years at Tulane University in New Orleans before moving to Little Rock.
Kimo’s Commitment to the Histio Community:
I was honored when asked to be considered for the position on the Board of Trustees as I felt this was a place that connected the families of patients with histiocytic disorders with those that studied and cared for those patients and families.
I am excited to be a part of the board at the Histiocytosis Association as it allows me to give back to a community of patients, families, clinicians, and scientist that I have been a part of now for over 30 years.
Former Board Trustees
Medical and Scientific Advisory Committee
To assure that our contributions and those of our donors, both conceptual and financial, continue to have maximum impact, particularly in view of the rapidly advancing knowledge in this field, the Board of the Histiocytosis Association has established a Medical and Scientific Advisory Committee (MSAC). This committee is intended to further advance our efforts to most rapidly and effectively obtain and translate new knowledge in these diseases to benefit the outcome of children and adults (and their families) with these difficult diseases. The MSAC provides guidance to the Association at several levels–assuring that grant funding decisions are wise, particularly in the face of rapidly progressing knowledge in the field, and that the broad and strategic directions of the Association remain cutting edge. The MSAC is composed of nationally and internationally prominent investigators, ranging in interest and expertise from basic scientific to translational to clinical studies. We are looking forward to the MSAC adding important insights to future planning of the Histiocytosis Association and to providing guidance in maximizing the research contributions of the Association and our donors to the conquering of these diseases.
Stephan Ladisch, MD
ChairmanChildren’s National
Medical Center
Washington, DC USA
Stephan Ladisch, MD
Stephan Ladisch graduated from the University of Pennsylvania and completed his pediatric residency at Children’s Hospital of Boston. He first became interested in the histiocytoses during his fellowship in pediatric oncology at the National Cancer Institute, where he discovered an immunodeficiency syndrome associated with FEL (now known as a form of HLH). In 1978, he joined the faculty of the University of California, Los Angeles (UCLA), where he continued his research in histiocytosis and in cancer biology and has since been actively involved in developing histiocytosis clinical trials. He became Professor of Pediatrics in 1986, and in 1991, he was recruited to Children’s National Medical Center (CNMC) to direct and develop the new Center for Cancer and Transplantation Biology at the Children’s Research Institute (CRI). He has also served as CRI’s first Scientific Director (1998-2005) as Vice Chairman of the Department of Pediatrics, and is Program Director of the NICHD-funded Child Health Research Center at CNMC since 2000. He holds the Bosworth Chair in Cancer Biology and is Professor of Pediatrics, Biochemistry, and Molecular Biology at George Washington University (GWU).
Dr. Ladisch has an international reputation in pediatric oncology and in histiocytosis, and is the author of more than 150 peer-reviewed articles in the areas of histiocytosis, cancer biology and immunology, and pediatric oncology, and he is on the editorial board of several journals. He has trained numerous graduate students and postdoctoral fellows, many of whom have gone on to academic positions. He is a member of several academic societies, including the Society for Pediatric Research and the American Association for Cancer Research, and is a Fellow of the American Academy of Pediatrics. His training activities also include a major role in developing the multidisciplinary graduate student training program at GWU, where he served as Director of the Institute for Biomedical Sciences. He is a member of the National Institutes of Health College of Scientific Reviewers.
Dr. Ladisch’s laboratory focuses on membrane gangliosides, their synthesis and shedding, and their roles in cell signaling, tumor biology and immunology, as well as in some forms of childhood histiocytosis. His research has been funded by the National Institutes of Health since 1980. He is a founding member and past-president of the Histiocyte Society and former Chairman of the Board of Trustees and Scientific Committee of the Histiocytosis Association.
Dr. Ladisch currently serves as the Chairman of the Medical and Scientific Advisory Committee of the Histiocytosis Association.
Oussama Abla, MD
The Hospital for Sick Children(SickKids)
Toronto, ON Canada
Oussama Abla, MD
Eli Diamond, MD
Memorial Sloan Kettering Cancer CenterNew York, NY USA
Read Bio Preview modal-Eli Diamond, MD
Dr. Eli Diamond is a neurologist and neuro-oncologist at Memorial Sloan Kettering Cancer Center. His training is in treating brain tumors and neurologic complications of cancer. He has been treating histiocytosis since he was in training in 2011 and this area is now his primary clinical and research focus.
Eli has conducted several research studies and clinical trials for adult patients with histiocytosis, including the trial that led to FDA approval of vemurafenib for BRAF-mutated Erdheim-Chester disease. He has implemented many other new treatments for patients with histiocytosis. Eli has lead several research studies about gene mutations in histiocytosis, as well as related to symptoms, quality of life, and caregiver needs.
Eli’s Commitment to the Histio Community:
I hope that my knowledge and passion for histiocytosis are an asset for the patient community in my participation as a Board of Trustees member and as the Chair of our Scientific Committee. In that role, I work with my colleagues to align our scientific and research priorities together with the needs, goals, and values of histiocytosis patients and families.
Thomas Gross, MD
University of Colorado Anschulz Medical CampusAurora, CO USA
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Jan-Inge Henter, MD
Karolinska University HospitalStockholm, Sweden
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Meriam Merad, MD, PhD
Icahn School of Medicineat Mt. Sinai
New York, NY USA
Milen Minkov, MD
St. Anna Children’s Cancer Research InstituteVienna, Austria
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Carlos Rodriguez-Galindo, MD
St. Jude Children’s Research HospitalMemphis, TN USA
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Barrett Rollins, MD, PhD
Harvard Medical SchoolDana-Farber Cancer Institute
Boston, MA USA
Barrett Rollins, MD, PhD
Kimo Stine, MD
University of Arkansas for Medical SciencesLittle Rock, AR USA
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Dr. Kimo Stine is a Professor of Pediatrics at the University of Arkansas for Medical Sciences practicing at Arkansas Children’s Hospital in Little Rock, Arkansas. Kimo has provided clinical care to children with histiocytic disorders, publish on their treatment options, and been a part of an international clinical trial to improve the outcome of children with LCH.
He attended medical school at the University of Kansas in Kansas City, KS, where he also completed his Pediatric Residency. He did a fellowship in Pediatric Hematology Oncology at Duke University and spent 2 years at Tulane University in New Orleans before moving to Little Rock.
Kimo’s Commitment to the Histio Community:
I was honored when asked to be considered for the position on the Board of Trustees as I felt this was a place that connected the families of patients with histiocytic disorders with those that studied and cared for those patients and families.
I am excited to be a part of the board at the Histiocytosis Association as it allows me to give back to a community of patients, families, clinicians, and scientist that I have been a part of now for over 30 years.
Robert Vassallo, MD
Mayo ClinicRochester, MN USA
Sheila Weitzman, MD
The Hospital for Sick Children(SickKids)
Toronto, ON Canada
Sheila Weitzman, MD
Histiocyte Society
Committed to Research
The Histiocyte Society is a professional medical association comprised of more than 200 physicians and scientists from around the world. Members of the organization are considered to be the leaders in understanding and treating histiocytic disorders. The Society is committed to advancing knowledge about histiocytic disorders and improving outcomes for patients through the planning, development, sponsorship, and oversight of clinical research.
True Partners
For more than 35 years, the Histiocytosis Association has served as a partner, secretariat and the primary source of funding for the Histiocyte Society. The Association’s support of the Society includes:
- Organizing and managing the Society’s annual scientific and Executive Board meetings,
- Managing the overall organizational, administrative and financial operations,
- Aiding in the development of organizational guidelines and operating procedures,
- Building, developing and maintaining the organization and annual meeting websites,
- Facilitating communication between Society members and the Executive Board, and
- Building and managing the Society’s membership database.
Conducting these activities alleviates the Society’s leadership of the administrative duties associated with running a volunteer-based, nonprofit organization and allows them to focus solely on research and treatment.
The partnership is demonstrated again each year during the Association’s research funding cycle. The Society’s Scientific Committee conducts a comprehensive review of the applications for funding received by the Association. This is the first and a vital step in the overall review process and provides the basis for the Association’s Board of Trustees to select the very best applications for funding.
Advancing Treatment
Through extensive research and collaboration, the Histiocyte Society has made numerous, significant strides in the fight against histiocytic disorders. The Society has established scientific standards for histiocytic disorders that are accepted worldwide; they include:
- A common language of uniform disease classification
- Standardized diagnostic criteria
- Guidelines for patient evaluation and follow up
The Society remains dedicated to facilitating essential and innovative clinical research – developing critical knowledge and increasingly effective treatments in the pursuit of a cure.
Building Knowledge
The Histiocyte Society hosts an annual scientific meeting in different locations around the world. Attendance is open to members of the Society as well as other professionals working in the field of histiocytic disorders and related studies. Presentations include the results of completed research studies, as well as proposals for new studies. This interactive forum allows the best and brightest minds in the histiocytosis community to share the most progressive information and to shape the future of research. Beyond the prolific exchanges that occur during the meeting, presenters work collectively to extend their reach by publishing subsequent articles and manuscripts in scientific journals worldwide.
In 2020 due to the COVID-19 pandemic, the Histiocyte Society was unable to meet in person for their regularly scheduled annual meeting. However, in order to maintain momentum and continue providing quality updates and education, the Executive Board quickly pivoted to hosting online webinars for doctors, researchers and scientists. These webinars have proven to be greatly beneficial to continuing the work of advancing histiocytosis research.
Annual Meeting Programs
Click on the here to view a previous years annual meeting program.