Monoclonal Gammopathy of Renal Significance (MGRS): Bridging the Gap Between Hematology and Nephrology

Abstract Monoclonal Gammopathy of Renal Significance (MGRS) is a clinical entity characterized by renal damage caused by monoclonal proteins secreted by clonal plasma or B-cell proliferative disorders, without meeting criteria for overt hematologic malignancies like multiple myeloma or lymphoma. From a hematologist's viewpoint, early identification of the underlying clone is crucial for guiding targeted therapy to preserve renal function. MGRS lesions are classified into organized deposits (e.g., AL amyloidosis), nonorganized deposits (e.g., monoclonal immunoglobulin deposition disease), and lesions without immune deposits (e.g., thrombotic microangiopathy). Diagnosis requires kidney biopsy with immunofluorescence and electron microscopy. Clone-directed therapies, such as daratumumab-based regimens for plasma cell clones, have improved hematologic and renal outcomes. Renal transplantation is feasible in selected patients with controlled disease. In conclusion, hematologists play a pivotal role in MGRS management by identifying the pathogenic clone and initiating prompt, targeted treatment to prevent irreversible renal damage. Ongoing research into novel agents and biomarkers promises better prognosis.