Effect of cyclosporine A on the corneal inflammatory response in herpes simplex virus keratitis

The effects of cyclosporine A (CyA), a selective inhibitor of T-lymphocyte function, on the corneal inflammatory response in herpes simplex virus (HSV) stromal keratitis was followed during the course of experimental HSV keratitis in the rabbit. The corneal response, characterized by polymorphonuclear leukocytes (PMN) and mononuclear cells, is an immunologically specific event that is dependent on the presence of viral antigens and immune cells. CyA treatment during the course of HSV keratitis resulted in a more severe and persistent stromal disease and more anterior chamber involvement than that seen in the solvent control-treated HSV-infected animals. Clinical observations correlated well with histological studies which confirmed a greater incidence of mononuclear and PMN infiltrates throughout the anterior chamber and stroma in the CyA-treated animals. HSV antigens were present in the corneas from both infected groups as observed by immunofluorescence staining, but endothelial localization of HSV antigens was seen primarily in the CyA-treated animals, often accompanied by cells in the anterior chamber. No significant differences in IgG and IgM staining in the diseased corneas and anterior chamber were noted between the CyA-treated and solvent control groups which suggests that there was no local B-cell immunosuppression.