P0480LENALIDOMIDE PLUS DEXAMETHASONE FOR PROLIFERATIVE GLOMERULONEPHRITIS WITH MONOCLONAL IG DEPOSITS

Abstract Background and Aims To evaluate the efficacy and safety of lenalidomide plus dexamethasone (LD) in patients with proliferative glomerulonephritis with monoclonal Ig deposits (PGNMID). Method Retrospectively analyzed the clinicopathological data of 6 PGNMID patients who treated with LD protocol from January 2010 to October 2019. Results All of the patients received LD treatment for ≥3 months after renal biopsy. 3 patients achieved renal remission. The renal remission rate was 50%. Light microscopy showed membranoproliferative glomerulonephritis and immunofluorescence showed single kappa type IgG3 was deposited in the mesangial region and the vascular loop. Before taking LD scheme, the median urinary protein were 7.76 (1.27,14.57) g/24h, the median serum creatinine 1.34 (0.8,3.27) mg/dL, the median albumin 34.5 (22.4,37.5) g/L. In 5 patients the concentration of serum free kappa and lambda light chain increased, but no patients with abnormal serum free light chain ratio. Complement C3 deteriorated in 2 patients, 2 cases of patients with monoclonal plasma cells, 0.7% and 0.5%, respectively. Immunofixation electrophoresis suggested that 1 patient had positive serum M protein for kappa type IgG3. At the last follow-up, median urine protein was 3.33 (0.33,11.23) g/24h, median serum creatinine was 1.23 (0.91,1.82) mg/dL, and median albumin was 35.9 (24.5,45.6) g/L. The concentration of 4 patients with elevated serum free light chain was lower than that before taking the drug. Two patients with decreased complement C3 increased to normal concentration at the last follow-up. However, the other two patients had a slight decrease in complement C3. The M spike did not turn negative during the follow-up in one patients. Adverse events included anemia, neutropenia, limb numbness, upper respiratory tract infection. Conclusion This study reported that lenalidomide plus dexamethasone may be effective in treating proliferative glomerulonephritis with monoclonal Ig deposits for the first time. More attention needs to be paid to the hematological adverse events during lenalidomide treatment. Table SEQ \* ARABIC 1 General information of 6 patients with PGNMID Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 Gender male male male male female female Age 40 62 51 61 48 38 Immunofluorescence IgG3-κ IgG3-κ IgG3-κ IgG3-κ IgG3-κ IgG3-κ Scr (mg/dL) 1.73 1.23 1.46 3.27 1.22 0.8 ALB (g/L) 36.4 37.3 32.7 27.1 22.4 37.5 eGFR (mL/(min·1.73 m2)) 49 63 65 19 62 93 Urine protein (g/24h) 4.3