C3 and systemic lupus erythematosus: The corresponding comparison between anti-U1-RNP-positive and -negative patients with SLE using our routine assays showed lower levels of C3 and less accrued organ damage in the patients who were anti-U1-RNP positive, with these individuals more commonly suffering from RP and fulfilling the hematologic disorder ACR criterion, as well as exhibiting lower counts of eosinophils, lymphocytes and monocytes.