Despite the wide use of intravenous cyclophosphamide (IC) in lupus nephritis (LN), there are few published studies showing the effect of this treatment on renal histology. In this prospective study, we report the effect of IC on the evolution of histopathologic features in successive renal biopsies in patients with LN. Thirty patients with class IV or V LN were started on IC (10-15 mg/kg) administered once every month for six months followed by three monthly for another six doses making a total of two years of therapy. The clinical course of the disease, serum creatinine and 24 hours urinary protein and creatinine clearance were tested at entry and subsequently during each follow-up visit. Repeat renal biopsy was performed after completion of two years of therapy. The mean serum creatinine of the study patients was 166.3 + 42 tmol/L at entry which decreased to 104 + 46.4 tmol/L at two years (P < 0.01). The mean 24 hours proteinuria decreased from 2.81 + 2.4 g at entry to 1.39 + 1.54 g at two years (P < 0.003) and the mean creatinine clearance increased from 58 + 31 ml/min at the start of treatment to 64 + 32 ml/min at two years of therapy (P < 0.05). Nine patients had serum creatinine of > 200 tmol/L, of whom six progressed to variable degrees of chronic renal failure. Repeat renal biopsy was performed in 21 patients. The original biopsy of these patients showed class IV in 17 and class V in four patients. On repeat biopsy, five of class IV disease had progressed to advanced sclerosis, four to class V, and five remained unchanged. The remaining three patients with class IV LN changed to one each of class I, II and III. Of the four patients with class V, one progressed to advanced sclerosis, one changed to class III and two remained the same. There was a significant decrease (P < 0.05) in the activity index although there was a significant increase in the chronicity index (P < 0.001). Multivariat analysis for possible risk factors for progression to chronic renal failure showed initial high serum creatinine to be a powerful predictor of renal failure. In conclusion, IC pulse therapy is effective in improving or stabilizing renal function in patients with class IV or V LN. The only poor prognostic determinant observed was higher initial serum creatinine value.
