Long-term follow-up of IgM monoclonal gammopathy of undetermined significance

Blood. 2003 Nov 15;102(10):3759-64. doi: 10.1182/blood-2003-03-0801. Epub 2003 Jul 24.


Little effort has been made to quantitate adverse outcomes of monoclonal gammopathy of undetermined significance (MGUS) of the immunoglobulin M (IgM) class, which progresses to lymphoma or Waldenström macroglobulinemia, whereas IgA and IgG MGUS progress to multiple myeloma, primary amyloidosis (AL), or a related plasma cell disorder. From 1960 to 1994, IgM MGUS was diagnosed in 213 patients in southeastern Minnesota. The end point was progression to lymphoma or a related disorder, as assessed with the Kaplan-Meier method. The 213 patients were followed up for 1567 person-years (median, 6.3 years per patient). Lymphoma developed in 17 patients (relative risk [RR], 14.8), Waldenström macroglobulinemia in 6 (RR, 262), primary amyloidosis in 3 (RR, 16.3), and chronic lymphocytic leukemia in 3 (RR, 5.7). The relative risk of progression was 16-fold higher in the patients with IgM MGUS than in the white population of the Iowa Surveillance, Epidemiology, and End Results Program. Cumulative incidence of progression was 10% at 5 years, 18% at 10 years, and 24% at 15 years. On multivariate analysis, the serum monoclonal protein and serum albumin concentrations at diagnosis were the only risk factors for progression to lymphoma or a related disorder. Risk for progression to lymphoma or a related disorder at 10 years after the diagnosis of MGUS was 14% with an initial monoclonal protein concentration of 0.5 g/dL or less, 26% with 1.5 g/dL, 34% for 2.0 g/dL, and 41% for more than 2.5 g/dL.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Amyloidosis / etiology
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Immunoglobulin M / immunology*
  • Leukemia, Lymphocytic, Chronic, B-Cell / etiology
  • Lymphoma / etiology
  • Male
  • Middle Aged
  • Paraproteinemias / complications
  • Paraproteinemias / mortality
  • Paraproteinemias / physiopathology*
  • Prognosis
  • Risk Factors
  • Survival Analysis
  • Waldenstrom Macroglobulinemia / etiology


  • Immunoglobulin M