title: Anti-Proteus antibodies in rheumatoid arthritis same-sexed sibships.
abstract: One hundred and forty-two RA patients and 121 of their healthy same-sexed siblings were tested for antibodies (Abs) to Proteus mirabilis and Escherichia coli by indirect immunofluorescence. Eighty-five individuals had active RA (CRP greater than 10 mg/l) and 57 inactive RA. The anti-Proteus Ab titre in the active RA group was significantly higher than in the inactive RA and non-RA group (P less than 0.0001 in both cases). Anti-Proteus Abs were significantly elevated in 30 individuals with active RA compared with their healthy HLA-identical same-sexed siblings (P less than 0.001). In 42 HLA-DR4 positive and 15 HLA-DR4 negative active RA patients, the Ab titre was non-significantly higher in the former group. Anti-E. coli Abs were not significantly elevated in any of the groups. Longitudinal data on 36 RA patients demonstrated a significant positive correlation between changes in CRP and changes in anti-Proteus antibody titres (r = 0.52, P less than 0.001). These observations require an explanation.
authors.affiliation: Department of Rheumatology, Royal Victoria Infirmary, Newcastle-upon-Tyne.
authors.forename: C M
authors.initials: CM
authors.lastname: Deighton
authors.forename: J W
authors.initials: JW
authors.lastname: Gray
authors.forename: A J
authors.initials: AJ
authors.lastname: Bint
authors.forename: D J
authors.initials: DJ
authors.lastname: Walker
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000276:immunology*; D005192:Family Health; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D011511:Proteus / Q000276:immunology*; D011513:Proteus mirabilis / Q000276:immunology; D012801:Sibling Relations
chemical_list: D000907:Antibodies, Bacterial; D006684:HLA-DR Antigens