Prognostic significance of C1q deposition in serial biopsies for predicating the long-term outcome in patients with proliferative lupus nephritis

Lupus nephritis (LN) is characterized by a highly variable clinical course. It has been reported that histopathologic lesions are risk factors for the progression of LN. The aim of this study is to investigate the relationship among the co-deposition of C1q, clinicopathological features, and renal outcomes in patients with LN. The clinical and histological parameters were studied in patients with International Society of Nephrology/Renal Pathology Society Class III or IV LN, who underwent two kidney biopsies. The patients were divided into two groups based on the glomerular C1q deposits: C1q-positive and C1q-negative. The impact of C1q status and longterm renal outcome on the doubling of serum creatinine and the rate of remission in the two groups were further investigated. Fifty-three patients had pure proliferative nephritis and 37.7% of these had a co-deposition of C1q. Doubling of serum creatinine was observed in 25% of patients with C1q-positive and 24.2% of patients with C1q-negative deposits. There was no difference between the two groups in terms of achieving complete or partial remission. The renal survival in the two groups was similar (P = 0.75). Upon repeat biopsy, the persistence of C1q positivity was associated with a poor outcome (P = 0.007). C1q deposition in the glomerulus in the baseline biopsy was not associated with a poor renal outcome or severe pathologic features in patients with proliferative LN. However, the persistence of C1q positivity in repeat kidney biopsy is associated with a poor renal outcome.