RECENT AND NEW STUDIES IN LANGERHANS CELL HISTIOCYTOSIS

Since 1985, when the International Histiocyte Society was founded, our knowledge of Langerhans cell histiocytosis, previously called histioc ytosis (HX), has dramatically increased. The Histiocyte Society has en couraged experts to work together to overcome principal controversies. Because it is a rare nonmalignant disease, international studies are particularly indicated to collect as many cases as possible, to compar e different experience, and to adopt common methods of evaluation of t he results. The main objectives of the Histiocyte Society-LCH Study ar e as follows: (1) to verify in a large population of patients the crit eria proposed by the Histiocyte Society for diagnosis and treatment of Langerhans cell histiocytosis; (2) to promote in situ investigations concerning the histopathogenesis of the disease and to identify new di agnostic and prognostic markers; (3) to design a common clinical stagi ng and follow-up system; (4) to verify the efficacy of different drugs (i.e., VP-16 and vinblastine) commonly used in the treatment of the d isease; and (5) to identify subsets of Langerhans cell histiocytosis p atients who need conservative or alternative treatments.