All subjects were seronegative for RA autoantibodies (cutoff for seropositivity: IgA ACPA > 1.2 U/ml, IgG ACPA > 10 U/ml, IgA RF > 25 IU/ml, and IgM RF > 5 IU/ml). The gene discussed is CD40LG; the disease is rheumatoid arthritis.