Antibodies against M. Bovis 65 KDa Heat Shock Protein and Its P180-188 Epitope in Sera of Patients with Juvenile Idiopathic Arthritis

We screened the levels of antibodies to M. bovis hsp65 and the 180-188 epitope by using ELISA in a cohort of 72 juvenile idiopathic arthritis (JIA) patients and 38 healthy controls. We analysed an association between antibody levels and rheumatoid factor, antinuclear antibodies, human leukocyte antigen B27 and the severity and the duration of the disease. The majority of anti-hsp65 antibodies in a cohort of JIA patients were of the IgG isotype (54.2%) with IgM (13.9%) antibodies increased to a lesser degree. IgG antibodies to M. bovis hsp65 (P<0.001) and the 180-188 epitope (P<0.001) were significantly increased in all of three disease onset types when compared with healthy controls. The highest levels of IgG antibodies to M. bovis hsp65 and its P180-188 epitope were observed in oligoarthritis and in patients with no X-ray changes and functional limitation, while the lowest antibody levels were detected in patients with the most severe stage of articular damage. When antibody levels to M. bovis hsp65 and the 180-188 epitope were examined within patient and control populations, significantly higher levels of IgG and IgM antibodies to M. bovis hsp65 were observed in both JIA (P<0.001) and healthy control (P<0.001) cohorts. These findings may suggest that the high levels of IgG antibodies to M. bovis hsp65 and its P180-188 epitope would reflect the least serious cases of JIA. Since IgM antibodies to M. bovis hsp65 and P180-188 M. bovis hsp65 epitope exceeded the control level in a few patients with JIA we believe they are not of concern.