Lymphocytes, macrophages and HLA-DR expression in vitreal and epiretinal membranes of proliferative vitreoretinopathy. An immunohistochemical study.

Proliferative vitreoretinopathy (PVR) as a severe complication of retinal detachment and also the main cause of failure in its treatments is not yet completely understood. In the present study, we examined 16 PVR epiretinal membrane specimens removed during vitrectomy from 16 patients with complicated rhegmatogenous retinal detachment by immunostaining of cryosections. We looked for the presence of lymphocytes and detected helper/inducer T lymphocytes (CD4+), suppressor/cytotoxic T lymphocytes (CD8+), B lymphocytes (CD22+), macrophages (CD68+), and HLA-DR expression. The results showed that 6 out of 16 specimens reacted positively with monoclonal antibody against the helper/inducer T cell subset (38%), 5 out of 16 reacted positively with a suppressor/cytotoxic T cell-specific monoclonal antibody (31%), 7 out of 16 reacted with B cell-specific monoclonal antibody (44%), and 14 out of 16 were positive for macrophages and HLA-DR (88%). Nevertheless, we think that the invasion of macrophages and lymphocytes into the membranes is not the cause for the pathogenesis, but a secondary event that might further complicate the course of the disease.