PTGER3 and systemic lupus erythematosus: (3) Indirect ELISA was performed to determine the levels of EP1–10 in serum of SLE patients and HCs, and we found EP1, EP2, EP3, EP4, EP6, and EP10 levels were increased in SLE patients compared with HCs, while after Bonferroni correction, only EP1, EP3, EP4, and EP6 levels were elevated.