Levels of immunoglobulins (G, A and M) and circulatory immunocomplexes in Nigerians with joint pains.

Serum immunoglobulin (G, A and M) and circulating immune complex concentrations were measured in eighty-three Nigerians having joint pains and forty apparently healthy Nigerians by the single radial immune-diffusion and polyethylene glycol precipitation methods respectively. The IgA level was significantly lower and IgM statistically higher in patients with joint pains than the controls. There was however no significant difference between the mean IgG concentrations in patients with joint pains and controls. The observed low circulating IgA levels could be as a result of depressed thymic activity, development of autoimmunity or utilization in immune complex formation. The mean concentration of soluble immune complexes was significantly higher in patients with joint pains than in the apparently healthy subjects. These immune complexes some of which may remain localized in the surface of cartilages, ligaments and menisci would cause activation of complement resulting in persistent inflammation and joint pains in these patients.