Increased number of T cells in bone marrow of ITP patients. Flow cytometric analysis of CD3⁺ T cells in blood (A) and bone marrow (B) from ITP patients (n = 5) and controls (n = 6). The results are given as percentage of CD3⁺ cells within the lymphocyte population gated in the forward and side scatter dot plot. Immunohistochemistry (C) and enumeration of CD3⁺ T cells on bone marrow biopsies obtained from untreated and newly diagnosed ITP patients (n = 17) and controls (n = 7). These results are given as number of CD3⁺ cells per cross-sectional area (mm²). Data are presented as means plus or minus SEM.