Further, IgG anti-IGKC2−19 (OR 4.679), IgG anti-IGKC2−19 HNE (OR 3.206), IgM anti-IGKC2−19 (OR 12.665), and IgM anti-IGKC2−19 HNE (OR 8.095) showed risks for RA development (Table 4). Here, CD40LG is linked to rheumatoid arthritis.