Search

Reactive arthritis (ReA) is believed to be 'triggered' by infection with certain bacteria. When the proliferative responses of mononuclear cells (MC) obtained from the synovial fluid (SF) of ReA patients were examined, it was found that they responded maximally to the specific organism responsible for the preceding infection. The response was shown to be due to Class II M HC-restricted T cells by inhibition experiments using cyclosporin A and monoclonal antibodies. Significant SFMC responses to additional organisms associated with ReA were also recorded; since there was no serological evidence of preceding infection by these organisms, this finding suggests that these bacteria share common T cell-recognized antigenic epitopes. The corresponding responses by peripheral blood mononuclear cells (PBMC) were much lower and often barely detectable, whereas their responses to PHA were consistently higher than those of SFMC. These results, combined with evidence that bacterial antigens localize in the joint, indicate that a bacteria-specific. T-cell-mediated response may play a central role in the pathogenesis of ReA. [ABSTRACT FROM AUTHOR]

We and others have previously shown that synovial fluid (SF) mononuclear cells (MC) from patients with both reactive arthritis and other inflammatory arthritides proliferate in vitro in response to bacteria clinically associated with the triggering of reactive arthritis. In all cases, such SFMC responses are greater than the corresponding peripheral blood (PB) MC responses, often markedly so, and the mechanism for this is unclear. We have investigated this phenomenon by comparing the relative abilities of irradiated non-T cells derived from PB and SF to support autologous T cell responses to ReA-associated bacteria. Seven patients whose SFMC had been shown previously to respond to bacteria were studied. We demonstrate antigen-specific responses of PB T cells to bacteria in the presence of SF non-T cells which are in marked contrast to the minimal responses of either unfractionated PBMC or PB T cells reconstituted with PB non-T cells. We also show that PB, but not SF T cells respond strongly to autologous SF non-T cells in the absence of antigen or mitogen. These findings demonstrate that SF antigen-presenting cells (APC) are potent activators of PB T cells. We conclude that the contrasting responses of SFMC and PBMC to bacterial antigens may be accounted for at least in part by an enhanced ability of SF APC to support T cell proliferative responses. [ABSTRACT FROM AUTHOR]

Interleukin 2 (IL-2) production and proliferative responses of peripheral blood mononuclear cells (PBMC) stimulated with three concentrations of PHA were measured in 75 patients with rheumatoid arthritis (RA) and 25 normal controls. All patients were on a standard therapeutic regime, and were assessed for disease activity by clinical and laboratory criteria. Rheumatoid cells showed significantly lower IL-2 production and proliferation than normal PBMC at all PHA doses. These differences were not attributable to different kinetics. Within the rheumatoid population, both IL-2 levels and proliferation were lower in patients with active disease than those with inactive RA. Patients with extra-articular disease showed the most pronounced defects. Proliferative responses showed an inverse correlation with clinical indices of disease activity but not with measures of the acute phase response. Rheumatoid patients had higher proportions of CD4+,TFR+ andTac+ lymphocytes than controls. Both proliferative responses and IL2- levels showed a positive relationship with the proportion of CD4+ cells, and an inverse relationship with Tac+ lymphocytes. Monocyte depletion and partial reconstitution resulted in an increase of both proliferation and lL-2 production, which was more marked in RA patients, suggesting that depressed IL-2 production may relate in part to monocyte effects. However, this cannot completely explain the magnitude of the defects observed, because normal monocytes did not increase the responses of rheumatoid lymphocytes, neither did rheumatoid monocytes suppress the responses of normal lymphocytes. [ABSTRACT FROM AUTHOR]