Specific cell-mediated responses to bacterial antigens and clinical correlations in reactive arthritis, Reiter's syndrome and ankylosing spondylitis.

In 2 cases of ReA seen during the acute phase and shown serologically to be due to Y. enterocolitica 0:3, the LT test showed a marked response using as antigen a freeze dried preparation of the causative organism. The test result correlated with the activity of the disease when repeated during a flare in the 1st case, and during remission in both. Patients with ReA/RS in general showed a significantly higher response to the yersinia and klebsiella antigens tested when compared to AS, suggesting an overall difference in cell-mediated immunity to these enteric bacteria. AS cases reacted significantly less than controls to K. pneumoniae under suboptimal conditions. K. pneumoniae was shown to enhance the LT response to yersinia, possibly through an adjuvant effect. This was found with AS, ReA and in controls, though whether it is of relevance in the etiopathogenesis of AS or ReA/RS remains far from clear. Acute non-traumatic synovitis of the knee, occurring de novo, or in association with psoriasis, inflammatory bowel disease, or as part of RS, may be accompanied by evidence of heightened reactivity to streptococci both by blood and synovial fluid mononuclear cells. In 1 case with serological evidence of streptococcal infection and erythema nodosum, these changes were found to parallel disease activity. ReA can, it appears, follow recent streptococcal infection, and be associated with B27.