Correlation between the clinical remission and histological remission in repeat biopsy findings of quiescent proliferative lupus nephritis

Background The optimal duration of maintenance therapy is controversial in proliferative lupus nephritis (LN). Discordance between clinical parameters of renal remission and histological findings has made repeat biopsy a compulsory tool to confirm the histological remission (HR), but the timing is debatable. Aim of this study was to find the correlation of sustained complete clinical remission (CR) in sever lupus nephritis with histological findings on repeat kidney biopsy and appropriate duration of treatment in maintenance phase after achieving complete clinical remission. Methods Repeated kidney biopsy (biopsy 2) was performed on patients of biopsy proven (biopsy 1) proliferative LN who had been in CR for at least 2-years. The clinical and histologic findings of these groups (biopsy 1 and biopsy 2) were compared. Total 29 patients were included for the final analysis. Group 2 was further divided as per the duration of sustained CR (>48 months & <48 months). Regression analysis were used to find predictors of the HR. Results Average time taken to achieve CR was 9(range 2-24) months. Average duration of follow up and maintenance therapy was 68 +/- 17.8 and 62.5 +/- 14.2 months respectively. In the repeat kidney biopsy, HR was observed in 93.1% patients. Immunofluorescence study (IF) was normal in 72% of the patients. Normal light microscopy (LM) findings were observed in 58% patients. Transformation from proliferative to nonproliferative LN was noted in 82% cases. Other than the duration of CR on maintenance therapy and blood pressure, rest of the variables failed to predict HR. In sustained remission for more than 48-months group, 100% patients achieved HR whereas only 84% in 24-48-months group. Conclusion Sustained CR on maintenance immunosuppressive therapy for more than 48-months duration predicts HR in repeat kidney biopsy findings in quiescent proliferative LN. Hence the minimum duration of maintenance therapy in proliferative LN should be at least for another 48 months after achieving CR.