Because recent studies indicated that CD4+ T cells (especially Th17 and Th1 cells) played a role in the inflammatory activity of BD8, 11, 24 and since a decreased expression of BTLA in CD4+ T cells was observed in ocular BD patients, we investigated the possible relationship between BTLA expression and the Th17 and Th1 cell responses in ocular BD patients and normal controls. Here, CD4 is linked to Behcet disease.