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

To prospectively determine, using two different assays, the lymphocyte proliferative response to a retinal autoantigen (S-antigen) in patients with Behçet's disease who are under treatment for ocular inflammation.

Patients were evaluated at each visit for signs of ocular inflammation. Peripheral blood leukocytes were harvested and cultured in the presence of bovine S-antigen in a standard culture assay, as well as by limiting dilution using multiple short-term T-cell lines.

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. However, an increase in established T-cell lines was correlated to the presence of ocular inflammation in all three patients. Ocular activity was associated 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.

An increase in S-antigen-responsive lymphocytes is found in the peripheral blood of patients with Behçet's disease during episodes of ocular inflammation. This increase cannot be measured using standard proliferation assays but requires the use of techniques exploiting the principles of limiting dilution analysis.