Prospective determination of T-cell responses to S-antigen in Behcet's disease patients and controls

PURPOSE. TO prospectively determine, using two different assays, the lympho cyte proliferative response to a retinal autoantigen (S-antigen) in patient s with Behcet's disease who are under treatment for ocular inflammation. METHODS. Patients were evaluated at each visit for signs of ocular inflamma tion. Peripheral blood leukocytes were harvested and cultured in the presen ce of bovine S-antigen in a standard culture assay, as well as by limiting dilution using multiple short-term T-cell lines. RESULTS. Five patients were observed for 2 to 10 months. During follow-up, three patients had episodes of ocular inflammation. No consistent change in proliferative response was observed in standard proliferation assays. Howe ver, an increase in established T-cell lines was correlated to the presence of ocular inflammation in all three patients. Ocular activity was associat ed with an increase of 9- to 30-fold in the frequency of short-term T-cell lines. This increase returned to baseline within 1 to 3 months. CONCLUSIONS. An increase in S-antigen-responsive lymphocytes is found in th e peripheral blood of patients with Behcet's disease during episodes of ocu lar inflammation. This increase cannot be measured using standard prolifera tion assays but requires the use of techniques exploiting the principles of limiting dilution analysis.