Objective. The aim of this study was to investigate serum complement factor H (CFH) and its associations with clinical and pathological features in patients with LN.
Methods. Serum CFH was detected in 241 LN patients, 38 active and 11 inactive patients with SLE without clinical evidence of renal involvement and 51 normal controls. Serum CFH autoantibodies and CFH Tyr402His were screened in the 241 LN patients. CFH deposition in kidneys was detected in some patients.
Results. Serum CFH levels in patients with LN at active phase were significantly lower than in 38 SLE patients or in normal controls. No serum anti-CFH autoantibodies were detected in patients with LN, and there was no significant difference in CFH Tyr402His distribution between patients with LN and normal controls. Glomerular expression of CFH was stronger than in normal controls. Serum CFH levels were mildly negatively associated with SLEDAI scores (r = −0.204, P = 0.001) and positively associated with serum C3 (r = 0.367, P < 0.001) and haemoglobulin levels (r = 0.193, P = 0.003). Patients with LN class III, subclass IV-S and those with thrombotic microangiopathy had the lowest serum CFH.
Conclusion. Serum CFH levels were associated with disease activity of LN.