As shown in Figure 4, SLE patients presented with a higher level of serum EP1 (P = 0.001, Figure 4A), EP2 (P = 0.009, Figure 4B), EP3 (P = 0.001, Figure 4C), EP4 (P < 0.001, Figure 4D), EP6 (P < 0.001, Figure 4F), and EP10 (P = 0.044, Figure 4J), while the levels were similar in EP5 (Figure 4E), EP7 (Figure 4G), EP8 (Figure 4H), and EP9 (Figure 4I) between two groups. Here, PTGER3 is linked to systemic lupus erythematosus.