Secretory IgA: immune defence pattern in ankylosing spondylitis and klebsiella.

Saliva secretory IgA (sIgA), secretory component (SC); serum immunoglobulins (IgG, IgA, IgM), complement (C3, C4), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were performed in 32 patients with ankylosing spondylitis and 29 normal controls. They were investigated for carriage in the faeces of Klebsiella spp. on 3 occasions over the previous months. Throat swabs and urine were cultured at the same time as immunological estimations were done. 24-hour urine sIgA specimens were studied in 13 patients and 12 normal controls. Significantly raised mean values of saliva sIgA and serum IgG, IgA, C3, and C4 were found in patients with raised values of serum ESR and CRP levels when correlated with controls. Raised values of sIgA in saliva, which is an important factor of the local immune defence mechanism of mucosal surfaces, suggests the presence of an antigenic stimulus from the gastrointestinal system in ankylosing spondylitis during activity of disease.