[Macrophages and HLA-DR expression in proliferative vitreoretinopathy]

Macrophages and macrophage-like cells have been reported as cellular components of epiretinal and vitreous membranes. The origin and function of these versatile cells in the membranes are not fully understood. In the present study we used monoclonal antibodies reacting with macrophages, HLA-DR and monocytes (OKM5) to investigate cells in 52 specimens of various human epiretinal and vitreous membranes collected by vitrectomy. The results show that more than 80% of all membranes are positive for macrophage and HLA-DR antigen. HLA-DR is considered to be expressed by the macrophages. Cells reacting with antimonocyte (OKM5) are seen sporadically only in proliferative diabetic retinopathy. These results are discussed with respect to the possible origin of the macrophages and their important role in the development and formation of epiretinal and vitreal membranes.