ICAM-1 expression on the surface of T lymphocytes in patients with uveitis: a comparative study between the eye and peripheral blood.

Purpose: We studied the surface expression of intracellular adhesion molecule 1 (ICAM-1) on peripheral and intra-ocular T lymphocytes in patients with active uveitis.

Methods: Two-colour flow-cytometric analysis was performed on cells isolated from aqueous humour and peripheral blood of 23 patients with active uveitis and 16 control patients who were to undergo cataract extraction, in order to determine the percentage of cells expressing CD4, CD8 and ICAM-1 (CD54) molecules.

Results: In the aqueous humour of patients with uveitis, we found an increase in the percentage of CD4+ and CD8+ lymphocytes, co-expressing the ICAM-1 molecule as compared to control patients (p < 0.0001). In peripheral blood, these uveitis patients exhibited a significant decrease in the percentage of CD4+ICAM-1+ (p = 0.0106) and CD8+ICAM-1+ (p = 0.0014) as compared to control subjects. The comparative study of cells from the aqueous humour and peripheral blood showed that the percentage of CD4+ICAM-1+ cells was higher in the aqueous humour (p < 0.0001). Comparison of the aqueous humour and peripheral blood for CD8+ICAM-1+ cells revealed no significant differences. In addition, we found a high negative correlation for the CD8+ICAM-1+ subset between the aqueous humour and peripheral blood.

Conclusions: Our results suggest a greater local participation for CD4+ICAM-1+ cells but not for CD8+ICAM-1+ cells in the pathogenesis of uveitis.