IMMUNE-REACTIONS IN CORNEAL HERPETIC DISEASE

The destructive effects of herpetic ocular involvement involve both th e cytotoxic effects of the viral particles directly and a variety of i mmunological mechanisms that are activated even after the acute stage of infectious disease has passed. These so-called noninfectious immune reactions represent a host response to rid the body of an antigen tha t can never be completely eradicated. Herpes simplex virus (HSV) prese nts in several ways, including infectious epithelial keratitis and ker atouveitis, and as several conditions that have a proposed immunologic al basis. In managing herpetic conditions, one should always consider these immune-based phenomena, as erroneous treatment directed only tow ard the virus can result in progressive injury to the eye. The clinica l and experimental support for the immune response accompanying HSV ke ratitis is well established. These changes are classified on the basis of the structures involved. First, a low-grade immune response can be associated with epithelial basement membrane changes in epithelial tr ophic ulcers. Second, the stroma can involve several types of reaction s, including stromal interstitial keratitis, Wessely immune rings, lim bitis, and disciform keratitis. Third, an immunological basis is belie ved to be responsible for the endotheliitis that can accompany herpeti c disease. Clearly, there are other forms of herpetic involvement that are, in part, immune-based, such as herpetic iridocyclitis, but this chapter is limited to those involving the cornea.