Experimental ulcerative herpetic keratitis. III. Evaluation of hyperimmune gammaglobulin therapy

The value of hyperimmune gammaglobulin (HGG) therapy in ulcerative herpetic keratitis was assessed in rabbits. HGG treated of early disease in normal rabbits was very effective, producing a 10-fold rise in the virus concentration needed to infect 50% of sites (CID50) and an 88% inhibition of ulceration after 2 days. The efficacy of the gammaglobulin preparations tested depended on their anti-HSV antibody content. Established disease was considerably less responsive to HGG therapy. No conclusive effect of HGG therapy could be demonstrated in rabbits with a previous HSV skin infection ('immunised'). Corticosteroid-induced geographic ulceration in immunised rabbits was not prevented by concurrent HGG therapy. The findings indicate that HGG is unlikely to represent a useful therapy for ulcerative herpetic keratitis but that it may be valuable in primary disease and in long-term prophylaxis.