Class IV-G and IV-S lupus nephritis in Chinese patients: a large cohort study from a single center.

This study is to assess the difference between IV-G and IV-S in a large cohort of Chinese patients with lupus nephritis. The detailed data of patients with subclass IV-G and IV-S were retrospectively analyzed. Serum ANCA and anti-C1q antibodies were detected. A total of 172 cases were classified as class IV, including 152 cases with IV-G and 20 cases with IV-S. In IV-S, the level of haemoglobin was significantly higher (P = 0.024), proteinuria was milder (P = 0.003), serum creatinine was lower (P = 0.021), serum C3 was higher (P = 0.045) and the ratio of positive serum anti-cardiolipin antibodies was higher (P = 0.014). On pathological evaluation, the ratio of glomerular fibrinoid necrosis was significantly higher (P = 0.006) and the score of endocapillary hypercellualrity, interstitial inflammation and total activity indices was significantly lower (P < 0.001, P = 0.01, P = 0.006, respectively) in IV-S. The frequency of serum ANCA was significantly higher in IV-S than that in IV-G (20 vs 4.6%, P = 0.008). The frequencies of anti-C1q IgG1 and IgG3 subclass were significantly higher in IV-G (P = 0.006, P = 0.011, respectively). There are significant differences in clinical and pathological manifestations between IV-S and IV-G lupus nephritis which need further investigation.