title: Laboratory persistence and clinical progression of small monoclonal abnormalities.
abstract: Monoclonal gammopathy of undetermined significance (MGUS) that presents with no quantifiable M spike on immunofixation electrophoresis (IFE) can be termed IFE MGUS. We retrospectively identified patients with IFE MGUS who were monitored with at least 1 subsequent assessment that included an IFE, and evaluated the persistence of the monoclonal protein and the progression of disease. Although the monoclonal proteins persisted in the majority of patients, 16% did not experience this persistence, and had no documented immunomodulatory therapy. After a median follow-up of 3.9 years, the disease clinically progressed in 14 patients (3.2%). Eight of these 14 patients with clinical progression had an immunoglobulin (Ig) A IFE M protein and 6 had an IgG M protein. This study demonstrates that in some patients with IFE MGUS, the M proteins are transient and that IgA IFE MGUS is more likely to persist and progress to myeloma.
authors.affiliation: Division of Clinical Biochemistry and Immunology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. murray.david@mayo.edu
authors.forename: David L
authors.initials: DL
authors.lastname: Murray
authors.forename: Justin L
authors.initials: JL
authors.lastname: Seningen
authors.forename: Angela
authors.initials: A
authors.lastname: Dispenzieri
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Snyder
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kyle
authors.forename: S Vincent
authors.initials: SV
authors.lastname: Rajkumar
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Katzmann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D004586:Electrophoresis; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology*; D047468:Immunoprecipitation; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000175:diagnosis* / Q000276:immunology; D009101:Multiple Myeloma / Q000276:immunology / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D007075:Immunoglobulin M