CELLS OF THE IMMUNE-SYSTEM AND THEIR CYTOKINES IN EPIRETINAL MEMBRANES AND IN THE VITREOUS OF PATIENTS WITH PROLIFERATIVE DIABETIC-RETINOPATHY

In the present study, we specifically investigated the presence of the main immune cells, namely T helper/inducer lymphocytes, T suppressor/ cytotoxic lymphocytes, B lymphocytes and macrophages, for HLA-DR antig en expression and the cytokines IL-1alpha and IL-2 in epiretinal membr anes of proliferative diabetic retinopathy (PDR) using immunohistochem ical staining. The levels of the two cytokines (IL-1alpha and IL-2) in the vitreous were measured by ELISA. The results show that 18 out of the 32 epiretinal specimens reacted positively with monoclonal anti-CD 4 (marker for T helper/inducer cell subset) antibody (56%), 21 reacted with monoclonal anti-CD8 (marker for T suppressor/cytotoxic subset) a ntibody (66%), 15 reacted with monoclonal anti-CD22 (marker for B lymp hocytes) antibody (47%), and 25 (78%) were positive for monoclonal ant i-macrophage and anti-HLA-DR antibodies. IL-1alpha and IL-2 were detec ted in the epiretinal membranes in 8 out of 13 tested cases (62%). How ever, in the vitreous, IL-1alpha was detected in only 3 out of 13 case s (70, 75 and 80 pg/ml, respectively), while IL-2 was not detected in any of the vitreous samples. The results clearly demonstrate that immu ne cells and their cytokines were found in about half of the epiretina l membrane specimens. The invasion of the immunocompetent cells in the membranes seems to be a secondary event. They would not participate i n the pathogenesis of PDR, but probably induce unspecific reactions an d thus complicate the disease.