PLA2R1 and erythema multiforme: The results demonstrated that both serum creatinine (OR: 10.35, 95% CI: 1.82–58.91, p = .01) and the PLA2R-IgG4/PLA2R-IgG ratio (OR: 1951.94, 95% CI: 15.48–246141.75, p = .002) were independent predictors of advanced EM stages (Table 4).