title: The detection of raised levels of IgM to Proteus mirabilis in sera from patients with rheumatoid arthritis.
abstract: An analysis by ELISA of 100 rheumatoid factor (RF)-positive sera selected at random from a collection of sera from patients with various auto-immune diseases and joint pains, and 100 RF-negative sera from the same collection matched by patient age and gender, showed that the RF-positive sera had highly significantly (p < 0.0001) raised levels of IgM antibody, but not IgG antibody, to Proteus mirabilis over those of the RF-negative sera. This response was subsequently found to be associated with sera from patients who clinically had rheumatoid arthritis (RA). Sera from the RA patients had significantly greater amounts (p = 0.026) of IgM antibody to P. mirabilis than to the other organisms tested and these values were also highly significantly different (p < 0.0001) from P. mirabilis IgM antibody levels in matched RF-negative sera. Sera from RA patients also had significantly greater amounts of IgA to P. mirabilis (p < 0.0001) and greater amounts of IgM to Escherichia coli (p < 0.0001) and Klebsiella pneumoniae (p < 0.0001) than those in matched RF-negative sera. Other classes of antibody to these organisms and all classes of antibody to Pseudomonas aeruginosa were not raised in the sera of RA patients over those of RF-negative controls. The IgM response in RA patients was not specific for only one O serotype of P. mirabilis but was associated with all 11 different O serotypes of P. mirabilis tested and those of other Proteus spp. Moreover, the IgM antibodies to Proteus spp. appeared to be independent from C-reactive protein and RF.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medical Microbiology, University of Dundee Medical School, Ninewells Hospital.
authors.forename: B W
authors.initials: BW
authors.lastname: Senior
authors.forename: P D
authors.initials: PD
authors.lastname: McBride
authors.forename: K D
authors.initials: KD
authors.lastname: Morley
authors.forename: M A
authors.initials: MA
authors.lastname: Kerr
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000251:Adenosine Triphosphatases / Q000276:immunology; D000907:Antibodies, Bacterial / Q000097:blood*; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000382:microbiology; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000276:immunology; D006460:Hemolysin Proteins / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D007136:Immunoglobulins / Q000097:blood*; D007711:Klebsiella pneumoniae / Q000276:immunology; D011513:Proteus mirabilis / Q000145:classification / Q000276:immunology*; D011550:Pseudomonas aeruginosa / Q000276:immunology; D012217:Rheumatoid Factor / Q000097:blood; D012703:Serotyping
chemical_list: D018528:ATP-Binding Cassette Transporters; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D006460:Hemolysin Proteins; D007136:Immunoglobulins; D012217:Rheumatoid Factor; D000251:Adenosine Triphosphatases; C086257:hemolysin B