Immune thrombocytopenia (ITP) is an autoimmune disease characterized by a peripheral destruction of platelets responsible for bleedings. Monocytes/macrophages play a double role by phagocyting platelets recognized by autoantibodies and by maintaining the autoimmune response via their antigen-presenting cell functions. Fcgamma receptors (FcγR), that are represented by activating receptors (FcγRI, FcγRIIa, FcγRIII) and an inhibiting one (FcγRIIb), are involved in the regulation of macrophages and have been reported to be dysregulated in autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematous. The aim of this study is to compare the expression of FcγR in patients with ITP on circulating monocytes and on splenic macrophages.