Rheumatoid Factor in Acute Viral Infections: Interference with Determination of IgM, IgG, and IgA Antibodies in an Enzyme Immunoassay

Abstract

IgM rheumatoid factor (RF), an autoantibody to the Fc fragment of IgG, was determined by solid-phase enzyme immunoassay (EIA). RF levels were significantly higher in patients with rubella virus infection than in patients with infections due to influenza virus, cytomegalovirus, respiratory syncytial virus, parainfluenza virus, adenovirus, mumps virus, or herpes simplex virus. To evaluate the role of RF in EIA determinations of viral antibodies, IgM RF from IgM-IgG cryoglobulin or control IgM was added to patient sera before assay for viral antibodies. IgM RF inhibited virus-specific IgG and IgA reactions and gave nonspecific IgM reactions in EIA for antibodies to rubella and influenza viruses, but had little or no effect on antibodies to cytomegalovirus. The minimal effective amounts of RF were 100-500 ng/ml for inhibition of IgG, 300-1,000 ng/ml for IgA, and 25-500 ng/ml for IgM. The control IgM preparation gave no such effects. These studies reinforce the need to eliminate RF interference in solid-phase EIA.

IgM, IgG, and IgA Antibody Responses to Influenza A(H1N1)pdm09 Hemagglutinin in Infected Persons during the First Wave of the 2009 Pandemic in the United States

“…These results suggest that IgM responses were seen largely in a Assay sensitivities were based on antibody responses obtained in convalescent-phase sera from A(H1N1)pdm09-infected persons. All had MN antibody titers of Ն40 and HI antibody titers of Ն20 (Veguilla et al [24]). Sera were grouped by age or by primary or nonprimary infections status determined as described in Materials and Methods.…”

Rapid Homogeneous Immunoassay Based on Time-Resolved Förster Resonance Energy Transfer for Serodiagnosis of Acute Hantavirus Infection

“…Notably, GullSORB treatment has been employed widely to eliminate the effect of rheumatoid factor, which causes false-positive IgM results (25,26). While IgG depletion eliminated the FRET signal from all the past-infection samples and the false-positive seronegatives, 58/61 (95%) acute-phase sera remained positive (cf.…”

Evaluation of an Enzyme Immunoassay for Detection of Immunoglobulin M Antibodies to West Nile Virus and the Importance of Background Subtraction in Detecting Nonspecific Reactivity

“…Numerous studies have been published demonstrating interference from RF and heterophile antibodies in immunoassays (8,9,17). Recent studies have shown the importance of including a background subtraction procedure to eliminate falsepositive reactions from interference by these substances when testing for WNV IgM antibodies.…”