FCGR2C and sarcoidosis: We have previously revealed that, in contrast to polymorphism of FCGR2B and FCGR3B, polymorphism of FCGR2A, FCGR2C and FCGR3A genes, encoding receptors for Fc fragment of immunoglobulin G (Fcγ receptors), play a role in increased level of circulating immune complexes with occurrence of Mycobacterium tuberculosis heat shock proteins in patients with sarcoidosis.