SCD5 and rheumatoid arthritis: In addition, serum sCD4 was also identified in patients of chronic inflammatory diseases such as RA [13], Sjogren’s syndrome [14], systemic lupus erythematosus (SLE) [14], common variable immunodeficiency [15], osteoarthritis (OA) [13], chronic renal failure [16], and localized scleroderma [17].