Further, levels of IgM against CFAH1211−1230 in RA patients were greatly higher than the levels in HCs by 1.21-fold (p = 0.0103) (Fig. 3c, left panel), and AUC values were 0.68 (with 81.7% sensitivity and 53.3% specificity) and 0.68 (with 77.1% sensitivity and 60.0% specificity) for detecting patients with RA and OA (Table 2). Here, CD40LG is linked to rheumatoid arthritis.