C3 and systemic sclerosis: Enhanced expression of proteins in SSc compared with IPF was demonstrated for α1-B glycoprotein, complement C3β, α1-antitrypsin, and haptoglobin β. Proteins with enhanced expression in SSc compared with sarcoidosis included prothrombin, thioredoxin, peroxisomal antioxidant enzyme (AOPP), calgranulin, and thioredoxin peroxidase 2.