C4A and rheumatoid arthritis: Dysregulation of CRP, C4, PEDF, and SAP has been linked to several cases of autoimmune disease including rheumatoid arthritis (RA) [43,45,46], systemic lupus erythematosus (SLE) [43,47,48,49,50,51,52], systemic scleroderma [53,54], and type 1 diabetes mellitus [55,56,57,58], among others [43,59,60,61,62], emphasizing the interconnectedness of stress, immune regulation and modulation, and autoimmune disease pathogenesis.