The rate of thrombocytopenia was higher in patients with hematological malignancies, and serum IgG and IgM levels were higher in patients with connective tissue diseases and hematologic malignancies; however, the differences were not significant (rate of thrombocytopenia, P = 0.058; serum IgG, P = 0.166, and serum IgM, P = 0.071). This evidence concerns the gene CD40LG and connective tissue disorder.