Renal pathologic spectrum and clinical outcome of monoclonal gammopathy of renal significance: A large retrospective case series study from a single institute in China

Abstract

To analysis the pathological spectrum and prognosis of monoclonal gammopathy of renal significance (MGRS) patients. Patients with renal biopsy-proven MGRS from 1999 to 2017 in Peking University First Hospital were included, clinical data, renal pathology type, treatment and prognosis were collected. One hundred and eighty-seven patients were enrolled, accounting for 0.7% of renal biopsies. Seventy-seven per cent of the MGRS patients were amyloidosis. Eighteen patients (9.6%) were monoclonal immunoglobulin deposition disease. Others included 10 patients (5.3%) with proliferative glomerulonephritis with monoclonal immunoglobulin (G) deposits, seven patients (3.7%) with cryoglobulinaemic glomerulonephritis, five patients (2.6%) with light chain proximal tubulopathy, two patients (1.1%) with fibrillary disease and one patient (0.5%) with C3 glomerulonephritis. Sixty-three per cent were treated with chemotherapy and/or stem cell transplantation. The mean follow-up time was 27 ± 32 months. One patient developed multiple myeloma at 17-month during follow-up. At the end of follow-up, 61 patients (33%) died, and 47 patients (25%) reached end-stage renal disease (ESRD). For the 144 amyloid patients, low estimated glomerular filtration rate (eGFR), decreased blood pressure, presence of cardiac involvement and absence of chemotherapy or high-dose melphalan/autologous peripheral blood stem cell transplantation were identified as independent risk factors for death. Low eGFR, decreased blood pressure, and presence of cardiac involvement were identified as independent risk factors for ESRD. For the 43 non-amyloid patients, no factor was identified for the risk of death. Low eGFR was identified as independent risk factor for ESRD. MGRS was an uncommon form of hematologic disorder related renal injury with a wide spectrum of pathologic lesions, and amyloidosis was the most common type. Treatment with chemotherapy and/or high-dose melphalan/autologous peripheral blood stem cell transplantation improved amyloid patients' survival.