The granulomatous reaction in herpetic stromal keratitis: immunohistological and ultrastructural findings.

A granulomatous reaction was identified in six corneal buttons obtained from patients with herpetic stromal keratitis. The inflammation, characterized by lymphocytes, plasma cells, macrophages and multinucleate giant cells, was associated with Descemet's membrane in five cases and with a break in Bowman's membrane in one case. The ultrastructural changes were documented by scanning electron microscopy in all cases. Transmission electron microscopy, performed in four cases, failed to disclose the presence of viral inclusions. Immunoperoxidase stains utilizing antibodies to the herpes simplex virus were done on all cases. Positivity (the presence of herpes simplex virus antigen or herpes simplex-like antigen) was detected within epithelium (three cases), within stroma (three cases), and within some inflammatory cells of the granulomatous reaction at Bowman's membrane. Positive staining was not detected in cells of the granulomatous reaction at Descemet's membrane. These results suggest that the reaction at Descemet's membrane, which has been found in a variety of corneal conditions, may be due to a poorly understood alteration in the antigenicity of Descemet's membrane.