Fig. 4: Distribution of different patterns of expression of CD2, CD25 and CD30 in/on MC in various groups of patients.

Expression of CD2, CD25, and CD30 in or on bone marrow MC was determined by flow cytometry and/or immunohistochemistry in 506 patients (10.95%) with mastocytosis, including cutaneous mastocytosis (CM, n = 42), “mastocytosis in the skin” (MIS, n = 10), indolent systemic mastocytosis (ISM, n = 364), smoldering systemic mastocytosis (SSM, n = 13), and advanced systemic mastocytosis (advSM, n = 77). In patients with ISM, MC expressed both CD2 and CD25, with or without CD30 expression, in a considerably higher number compared to patients with advSM. However, in patients with ISM there was a lower percentage of patients not expressing CD2 but still expressing CD25 and CD30, compared to SSM and advSM. In very few patients with SM, MC were found to lack CD2 and CD25, regardless of CD30 expression. MC mast cells.