C4A and synovial sarcoma: Currently, both clinical and laboratory features have been associated with increasing risks of developing NHL from SS; such features include major salivary gland enlargement, splenomegaly, lymphadenopathy, purpura, low complement level, especially C4, monoclonal gammopathy, cryoglobulinemia, neutropenia, and lymphopenia upon diagnosis of SS [2, 16, 21, 25–31].