Monoclonal gammopathy (MGRS), known as monoclonal immunoglobulinopathy of renal significance, is renal damage caused directly or indirectly by the monoclonal immunoglobulin of nephrotoxicity, or its components, produced by the clonal proliferation of abnormal B cells or plasma cells.
MGRS is defined as any B-cell or plasma cell monoclonal proliferation that meets 2 conditions: (1) the presence of one or more renal damages associated with monoclonal immunoglobulin produced by the B-cell or plasma cell monoclonal proliferation; and (2) the B-cell or plasma cell clone is incapable of causing neoplastic complications or does not satisfy current diagnostic criteria for hematologic neoplasms and requires specific therapy.
The updated definition of MGRS includes renal damage caused by monoclonal immunoglobulins and their components produced by all B-cell or plasma cell clonal proliferative disorders, including smoldering multiple myeloma, smoldering Wahl’s macroglobulinemia, and monoclonal B-lymphocytosis, treatment-naïve, low-risk chronic lymphocytic leukemia, and B-cell non-Hodgkin’s lymphoma.
Patients are advised to seek active medical attention after diagnosis of monoclonal gammopathy to avoid transformation of the condition to a malignant hematologic tumor.