Background: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, lupus nephritis (LN) is a widespread and serious complication and it is responsible for morbidity and mortality. This study aimed to detect the correlation between anti-C1q antibodies and LN activity.
Patients and Methods: A case-control study was conducted from September 2021 to September 2022.They were 30 healthy controls and 60 patients with SLE. The patients were divided into two groups: group 1 with active LN and group 2 with absent LN.

Results: The current study consisted of 72 females and 18 males. Regarding the renal biopsy, there were 8 (26.7%) patients in class I, 3 (10.0%) patients in class II, 11 (36.7%) patients in class III and 8 (26.7%) patients in class IV.
Our study found a significant difference between groups 1, 2 and the control group regarding Albumin/creatinine ratio, e GFR, SLEDAI score, and anti-C1q. We also revealed a significant positive correlation between anti-C1q and SLEDAI score, Urea, Creat, and Albumin/creatinine ratio.
Conclusion:
It is possible that anti-C1q antibodies may serve as an accurate serological indicator for identifying SLE individuals with active LN and active SLE disease.