Distinct Effects of Complement C4A and C4B Copy Numbers in Systemic Sclerosis Serological and Clinical Subtypes
Objective Complement component 4 (C4), encoded by C4A and C4B within the major histocompatibility complex (MHC) on chromosome 6, regulates the immune response and clears immune complexes. The variable copy number (CN) of C4 genes and retroviral human endogenous retrovirus K (HER…