HLA ANTIGENS AND LYMPHOCYTES IN PROLIFERATIVE VITREORETINOPATHY

An immunohistopathological study was performed on 33 epiretinal membra ne specimens obtained during vitreoretinal surgery from patients with rhegmatogenous retinal detachment complicated with proliferative vitre oretinopathy (PVR). Immunofluorescence and immunoperoxidase methods we re used to detect major histocompatibility complex or HLA antigens and immunocompetent cells, and to identify the cellular and the extracell ular component of the proliferative tissue. The following antigens wer e detected in epiretinal membranes: cytokeratin in 18 (of 18 cases stu died for this antigen), glial fibrillary acidic protein in 20 (of 20), vimentin in 20 (of 20), actin in 16 (of 18), fibronectin in 20 (of 20 ), macrophage CD68 in 16 (of 18), leukocyte common antigen in 12 (of 1 8), T-cell CD45R in 13 (of 22), HLA-ABC in 27 (of 33), HLADR in all th e 33 membranes and HLA-DR alpha chain in 32 of 33 membranes. We observ ed the presence of macrophages and of an activated T-cell population i n PVR membranes. HLA-DR antigen expression was found on pigmented and nonpigmented epithelial cells and on mononuclear cells in all epiretin al membranes. The HLADR expression on retinal pigmented epithelial cel ls could play a role in triggering a local immune response in PVR. The se findings suggest the involvement of immunological phenomena and pro bable interactions between the immune system and peptide growth factor s.