Monocyte-derived macrophages as helper cells in monocyte-mediated cytolysis

Effect of leukopenia on experimental post-traumatic retinal detachment

Macrophages are invariably present in the intraocular membranes of patients with traumatic proliferative vitreoretinopathy (PVR). There are two sources from which these macrophages could be recruited: adjacent tissues and the systemic circulation. In the study described herein, the role of circulating white blood cells and monocytes in experimental, traumatic PVR was studied. The circulating white blood cells of 20 rabbits were depleted by intravenous injection of strontium-89. Posterior perforating eye injury with subsequent intravitreal injection of autologous whole blood or autologous activated macrophages was then performed on these leukopenic animals. The experiments demonstrated that severe bone marrow depression reduced significantly the incidence of retinal detachments in eyes receiving whole blood, and reduced the severity of retinal detachments in eyes injected with activated macrophages. An association between the degree of leukopenia, monocytopenia, and protection from retinal detachment was demonstrated. These results support the hypothesis that macrophage infiltration is an important component of intraocular cellular proliferation, but does not exclude the role of other types of white blood cells in the pathogenesis of PVR.