Correlation between anti-Proteus antibodies and isolation rates of Proteus mirabilis in rheumatoid arthritis Iraqi patients

Abstract

Rheumatoid arthritis (RA) is a chronic inflammatory polyarthritic disease associated with remissions and exacerbations and characteristic genetic, clinical, pathological, and immunological features. The present study was designed to examine the evidence linking Proteus mirabilis to RA in some Iraqi patients. The study was carried out on 70 Iraqi RA patients, during the period from March 2010 to March 2011. For purposes of comparison, 10 of Systemic Lupus Erythematousus (SLE) patients and 10 of apparently healthy subjects were involved as a control groups. After bacterial isolation and identification, Enzyme linkedImmuno sorbent Assay (ELISA) technique has been applied for estimation of antibacterial antibodies.
Results of this study revealed that out of 70 urine samples of RA patients, E.coli was present in 12.9%, followed by P. mirabilis which present in 7.1%. Regarding SLE and healthy control group, urine samples were negative from any bacterial strains except E. coli, which present in about 10% of each group. Frequency of Proteus mirabilis in RA group was highly significant when compared with that of other groups (p<0.01). All rheumatoid arthritis patients and control groups were tested by ELISA technique for detection of IgM, IgG and IgA antibodies specific to Proteus mirabilis. Results demonstrated that the levels of these
antibodies were elevated in the sera of RA patients with a high significant degree, in comparison with control groups (p<0.01). The same sera were tested for anti- E. coli antibodies and the results showed that there was no significant difference in the IgM and IgG antibodies level to E. coli in RA patients when compared with control groups (p>0.05).
In conclusion, these findings suggested a possible association between infection with Proteus mirabilis and rheumatoid arthritis. The elevated levels of Proteus mirabilis antibodies within RA sera could be helpful in the identification of those patients during early stages of the disease.