Kidney Week

Abstract: FR-PO1081

Diagnosis and Outcomes of Monoclonal Gammopathy of Renal Significance: A Single Centre Study

Session Information

• Glomerular Diseases: Clinical, Outcomes, Trials - II
  October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

• Kousios, Andreas, Imperial College Healthcare NHS Trust, London, United Kingdom

Andreas Kousios,

• Duncan, Neill D., Imperial College Healthcare NHS Trust, London, United Kingdom

Neill D. Duncan,

• Roufosse, Candice A., Imperial College Healthcare NHS Trust, London, United Kingdom

Candice A. Roufosse,

• Cook, H. Terence, Imperial College of London, London, United Kingdom

H. Terence Cook,

• Charif, Rawya, Imperial College Healthcare NHS Trust, London, United Kingdom

Rawya Charif,

Background

Monoclonal Gammopathies of Renal Significance (MGRS) are caused by monoclonal immunoglobulins (MIg) produced by B cell or plasma cell clonal disorders, which do not meet criteria of symptomatic lymphoma or myeloma (MM). Treatment objective in MGRS is the preservation of kidney function.

Methods

Records of patients with native kidney biopsy during 2006 – 2017 were reviewed. Amyloidosis, C3GN and TMA were excluded.

Results

41 biopsies out of 4.374 (1%) were consistent with MGRS. Mean age at diagnosis was 63±12 years. Renal histological diagnoses included: proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) (n=16, 39%), monoclonal immunoglobulin deposition disease (MIDD) (n=13, 32%), light chain tubulopathy (LCT) (n=5, 12%), type-1 cryoglobulinaemic glomerulonephritis (n=6, 15%), fibrillary glomerulopathy (FibGN) (n=1, 2%). 22/41 patients had abnormal protein electrophoresis and/or free light chain ratio. 32/41 had bone marrow biopsy and haematological diagnoses included: MGRS with <10% plasma cells (n=22, 69%), smouldering myeloma (n=5, 15%), Waldenstrom’s Macroglobulinaemia (n=1, 3%), chronic lymphocytic leukaemia (n=3, 10%) and marginal zone lymphoma (n=1, 3%). 16 patients were treated with myeloma-based protocols (bortezomib ± autologous stem cell transplantation). In cases with very low or unidentifiable clone, treatment was heterogenous, including glomerulonephritis protocols (cyclophosphamide, steroids ±Rituximab) (n=16) or conservative management (n=9). During median follow-up of 26 months (4-123) in 38 patients, 26 had stable/improved renal function, 1 worsening renal function (>30% eGFR decrease) and 11 progressed to ESRD. 9 patients died (table 1).

Conclusion

Haematological assessment of MGRS must exclude symptomatic myeloma or lymphoma and identify the pathogenic clone to direct specific therapy. Case studies in our series indicate that early detection and treatment improves renal outcomes, however consensus diagnostic and treatment approaches are missing.