Recent advances in mastocytosis research - Summary of the Vienna Mastocytosis Meeting 1998

The term mastocytosis denotes a heterogenous group of disorders characteriz ed by abnormal growth and accumulation of mast cells in one or more organs. Cutaneous and systemic variants of the disease have been described. Mast c ell disorders have also been categorized according to other aspects, such a s family history, age, course of disease, or presence of a concomitant myel oid neoplasm. However, so far, generally accepted disease criteria are miss ing. Recently, a number of diagnostic (disease-related) markers have been i dentified in mastocytosis research. These include the mast cell enzyme tryp tase, CD2, and mast cell growth factor receptor c-kit (CD117). Several gain -of-function-mutations in the kinase domain of c-kit appear to occur in mas tocytosis supporting the clonal (neoplastic) nature of the disease. Also, c ertain point mutations appear to be associated with distinct variants of ma stocytosis, i.e. Asp-816-->Val with a subset of sporadic persistent (system ic) mastocytosis (mostly adults), and Gly-839-->Lys with (a subset of) typi cal pediatric (mostly cutaneous) mastocytosis. Another potential indicator of mast cell neoplasm is the T-/NK-cell-associated marker CD2. This antigen (LFA-2) is abnormally expressed on neoplastic mast cells in cases of syste mic mastocytosis or mast cell leukemia, but not found on normal mast cells. The mast cell enzyme tryptase is increasingly used as a serum-and immunohi stochemical marker to estimate the actual spread of disease (burden of neop lastic mast cells). The clinical significance of novel mastocytosis markers is currently under investigation. First results indicate that they may be useful to define reliable criteria for the delineation of the disease.