From the Guidelines
Monoclonal gammopathy (MG) is a condition characterized by the presence of abnormal proteins called monoclonal proteins (M proteins) produced by plasma cells in the bone marrow, with a prevalence of approximately 3.5% in the population over 50 years of age, as defined by the European Myeloma Network 1.
Definition and Types
Monoclonal gammopathy can be classified into different types, including:
- IgG and IgA MGUS, defined by a M-protein less than 30 g/L, bone marrow plasma cell percentage less than 10%, and absence of signs or symptoms related to multiple myeloma or other lymphoproliferative malignancies 1
- IgM MGUS, with some controversy concerning the diagnostic criteria, but generally defined by the presence of an IgM M-protein without bone marrow infiltration by lymphoplasmacytic lymphoma 1
- Light-chain MGUS, defined by an abnormal κ/λ free light-chain ratio, increase in concentration of the involved light-chain, and absence of expression of a monoclonal peak of immunoglobulin heavy-chain in the serum on immunofixation 1
Risk of Progression
There is an average risk of progression to multiple myeloma or other lymphoproliferative disorders of 1% per year, with patients with IgG or IgA MGUS typically progressing to multiple myeloma, and patients with IgM MGUS progressing to Waldenström’s macroglobulinemia or other lymphoproliferative disorders 1.
Management
Management of MGUS primarily involves regular follow-up with blood tests every 6-12 months to monitor protein levels and check for disease progression, with no specific treatment needed for MGUS itself, but treatment may be necessary if it progresses to multiple myeloma or other related disorders 1.
From the Research
Definition of Monoclonal Gammopathy (MG)
- Monoclonal gammopathy is a condition characterized by the presence of a monoclonal protein (M protein) in the blood, which can be indicative of various underlying conditions, including symptomatic multiple myeloma or other overt malignant lymphoid disorders 2.
- It can also result from a small and/or quiescent secreting B-cell clone, which is completely asymptomatic and requires regular monitoring only, defining a monoclonal gammopathy of unknown significance (MGUS) 2, 3, 4, 5.
Types of Monoclonal Gammopathy
- Monoclonal gammopathy of undetermined significance (MGUS) is a pre-malignant condition for Waldenström macroglobulinemia and other B-cell malignancies, defined by asymptomatic circulating IgM monoclonal protein below 30 g/L with a lymphoplasmacytic bone marrow infiltration of less than 10% 6.
- IgM monoclonal gammopathy of clinical significance is a condition where the monoclonal protein itself causes unique immunological and biochemical manifestations, such as cold agglutinin disease, type I and II cryoglobulinemia, IgM-associated peripheral neuropathy, Schnitzler syndrome, and IgM-associated AL amyloidosis 6.
Clinical Significance and Management
- The clinical significance of monoclonal gammopathy lies in its potential to progress to malignant conditions, such as multiple myeloma, AL amyloidosis, Waldenström macroglobulinemia, or lymphoma, with a risk of progression of approximately 1% per year for MGUS 2, 3, 4, 5.
- Management of monoclonal gammopathy involves regular monitoring, risk stratification, and treatment of underlying conditions, with the goal of preserving organ function and preventing progression to malignant conditions 2, 6, 3, 4, 5.