THE GUT AS AN INDUCTIVE SITE FOR SYNOVIAL AND EXTRAARTICULAR IMMUNE-RESPONSES IN RHEUMATOID-ARTHRITIS

Objectives-To analyse the immunological interactions between the gut l ymphoid tissue, synovium, and peripheral blood compartments in patient s with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Meth ods-Patients with RA and AS and healthy controls were orally or parent erally immunised with an influenza virus vaccine. Antigen-specific ant ibody responses were measured at the single cell level by ELISPOT assa y using lymphocytes isolated from peripheral blood and from enzymatica lly dispersed synovial tissues. Results-Both oral and parenteral immun isations induced antigen-specific antibody-secreting cells in the syno vial tissue of patients with RA. Parenterally immunised patients with RA showed significantly decreased antigen-specific antibody responses in peripheral blood compared with patients with AS and with healthy co ntrols. In contrast, oral vaccination evoked comparable peripheral blo od antibody responses in ail three study groups. Conclusions-Despite a decreased immune responsiveness in the systemic compartment, the func tional status of the gut-associated lymphoid tissue in patients with R A is intact. In addition, there is evidence that the lymphocytes in th e inflamed joints are accessible for signals both from the systemic an d mucosal compartments. The findings of immunological 'cross-talk' are relevant to future vaccination and tolerisation procedures in patient s with RA.