Among different EM stage, the intensity of the IgG4 deposit was much higher in stage 4 of PLA2R-related subgroup than that of PLA2R-unrelated subgroup (2.4 ± 0.5 vs. 1.3 ± 1.0, P = 0.032) (see Figure 3). Here, PLA2R1 is linked to erythema multiforme.