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32nd Annual Nikolas Symposium (Greek Histiocytosis Meeting)

In mid-May, I had the opportunity to once again attend the 32nd Annual Nikolas Symposium hosted by the Kontoyannis family and the Artemis Foundation (Histio Hellas) in Greece. The Nikolas Symposium was established in 1989 as a scientific think-tank focused on histiocytosis; it welcomes scientists, researchers and medical professionals from all over the world to examine, deliberate and debate the pathogenesis and structure of the diseases.1

As a member of the Steering Committee, the Histiocytosis Association helps to provide direction on potential speakers and topics, with the main expertise coming from the committee’s medical and scientific leadership.  

This year, the topic was “Tissue inflammation and the Langerhans cell histiocytosis lesion”. The four-day meeting had incredible speakers from the US, UK, Europe who were experts in basic science in areas relevant to the topic of the event but not necessarily knowledgeable or actively studying/treating histiocytosis.  

32nd Annual Nikolas Symposium Attendees

The first day was a warm welcome to familiar faces as well as new; the Nikolas Symposium brings together histio experts and experts in medicine/science outside of histiocytosis for a think-tank style meeting where both groups in individuals learn from each other and consider new possibilities for histiocytosis research.  

Dr. Barrett Rollins of Dana Farber opened the session with a welcome to all the guests and a history of the Symposium. Dr. Carl Allen of Texas Children’s Hospital provided an overview of LCH to the room, as many of the guests are new to histiocytic disorders and this information would help lay the foundation for conversations over the next several days. Finally, Astrid van Halteren gave a review of the 31st Nikolas Symposium in 2023.  

On the second day featured a talk by Jennifer Picarsic, Co-Director of Histiocytosis Program Cincinnati Children’s Hospital, who spoke about pathology of LCH; how to diagnose, re-learning what we think we know with the molecular microscope. One of the key points is that there are lots of inflamed tissue cells that also have mutations; these mutated cells call inflammation to the site. LCH presents on a spectrum, anywhere from single focal single system or multisystem multifocal; the complexity of LCH and the presence of inflammation can make it difficult to diagnose, can be diagnosed when it is not present, or misdiagnosed as another condition. BRAF V600E is used as a marker for diagnosis because it is present in at least 40% of people with LCH and the non-BRAF V600E biopsies can be more challenging. 

Additionally, Miriam Merad M.D.; Ph.D., Director of the Precision Immunology Institute at Mount Sinai School of Medicine in New York and the Director of the Mount Sinai Human Immune Monitoring Center (HIMC), discussed her role in histiocytosis research over the last 20-years, starting with her quest to understand the origin of the LCH cell.  

Most presentations over the next 2 days encompassed experts from various aspects of science and between the presentations, discussions on how this could apply to histiocytosis were had. The ‘external’ expert speakers included: 

  • Burkhard Becher, PhD University of Zurich 
  • Menna R. Clatworthy, NIHR Research Professor, University of Cambridge 
  • Thomas Cupedo, PhD, Erasmus MC 
  • Nicolas Gaudenzio, Research Director Inserm 
  • Martin Guilliams, Professor, Ghent University 
  • Mara Sherman, Associate Member Cancer & Biology, Memorial Sloan Kettering 
  • Frank J.T. Staal, PhD, Leiden University Medical School 
  • Isabelle Arnold Wallen, Assistant Professor, University of Zurich 
  • Benjamin Youngblood, PhD, St Jude Children’s Research Hospital 

The talks were invigorating and there was quite a lot of discussion on overlapping ‘issues’ including the role of the mast cell, t-cells, and eosinophils which hopefully will lead to collaborations between the histiocytosis experts and those who are experts in other areas of science and medicine. It is collaborations like this that lead to new discoveries – and that collaboration and learning is also what led to the discovery of the potential role of the BRAF mutation in histiocytosis when Dr. Barrett Rollins joined the Symposium for the first time. See the project(s) that followed, here

The Histiocytosis Association is forever grateful for all those involved in coordinating the Symposium and ensuring its continuation. It is undoubtedly a critical component to the progress that has been made over the years. We are incredibly thankful for their partnership in the search for cures. 


  1. [The following is abbreviated from the source of: About Us – Nicolas Symposium (; please visit to read the full story].  
    Nikolas Kontoyannis is the source of inspiration for this annual Symposium. At barely 4-weeks old, Nikolas was diagnosed with Histiocytosis X after his parents rushed him to the hospital with inexplicable skin rashes over his entire body. At the time, 1981, very little was known about histiocytosis, and treatment options were very limited. Between the ages of 6 and 7 he was diagnosed with ataxia and osteoporosis. It became apparent that he was also suffering from growth deficiencies, which brought about the need for growth hormone treatment, lasting almost 4 years. By the age of 7, CNS (Central Nervous System) involvement was detected, and Nikolas was showing signs of short-term memory loss and had started to develop learning difficulties. At 11 years of age hydrocephalus was detected. Nikolas had to have a ventriculostomy performed, shortly after which he started having seizures, prompting the need for medication which he takes to this day. Due to CNS involvement, problems and accidents relating to Nikolas’ balance, eating, drinking and movement increased over time; a fractured right hip and, when he was 29 years, a severe fall led a 6-hour operation to repair his right arm. These and other incidents further worsened his ability to walk and balance himself unaided. Since then, Nikolas has required 24-hour assistance to ensure his safety when moving around and to live as normal and happy a life as possible. 
    Faced with this rare disease and having been in the dark for so long Nikolas’ parents embarked on a journey of turmoil, pain and endurance but never gave up their fight to save him and learn more. Nikolas himself, as he grew older and more acutely aware of his situation, developed a spirit of his own and has proved to be a victorious warrior in his battle against the disease. 
    The Nikolas Symposium is an exceptionally poignant and important aspect of his life, and he remains to this day an active and proud spokesperson for the symposium named after him. 
    ‘The impact the disease has made on me and my life is almost beyond words. It sometimes makes me sad, angry and very tired. Sometimes my mind cannot figure it all out and the question is always, ‘why me?’ But the Symposium has shown me that I am not alone. My struggle has left me determined not to allow myself to settle for less in life…’ 
    Nikolas Kontoyannis  ↩︎