IgA nephropathy to proliferative glomerulonephritis with monoclonal IgAκ deposits: a pattern switch

We report the case of a 31-year-old male who presented with repeated episodes of nephritic-nephrotic syndrome in concomitance with infection. IgA was diagnosed and was initially responsive to treatment with immunosuppressors but further disease flare did not respond to treatment. Based on three consecutive renal biopsies over 8 years, a pattern switch from endocapillary proliferative IgA nephropathy to membranous proliferative glomerulonephritis with monoclonal IgAκ deposits was observed. Bortezomib-dexamethasone combination therapy finally led to a favorable renal response. This case provides new insights into the pathophysiological mechanisms of proliferative glomerulonephritis with monoclonal immunoglobin deposits (PGNMID), highlighting the importance of repeat renal biopsies and routine evaluation of monoclonal immunoglobin deposits in proliferative glomerulonephritis with refractory nephrotic syndrome.