This study addresses the molecular epidemiology of oral herpes viral infection in AIDS and seeks to understand the impact of these infections in terms of viral molecular pathogenesis and modulation of host response. Herpes viruses cause persistent infections and are shed into the oral cavity during immunosuppression resulting in increased morbidity and in the presence of AIDS defining oral lesions. The objective of these studies is to discern the prevalence of herpes viruses in saliva, blood, and oral disease, looking specifically at Hairy Leukoplakia (HLP) and (HIV) associated salivary gland disease to distinguish the character of infection, and to understand how the viruses modulate the host environment to cause these pathologies. The central hypothesis of this application is that herpes viral burdens vary with changes in immune status and drug regimen and that shedding and infection in the oral cavity results in pathologies such as HLP and HIVSGD that are a direct result of modulation of the cellular environment by these herpes viral pathogens. This study will determine whether herpes viral prevalence varies with changes in immune status and anti-AIDS drug regimen, based on a cross sectional studies that correlate herpes viral prevalence in tissue samples from diseased and non diseased oral tissues, saliva and blood to clinical parameters documented in patients charts from samples taken 1989/1990 and in present day specimens. Viral prevalence in these various specimens will be determined by quantitative polymerase chain reaction. Further, this study will determine if a herpes virus is the etiologic agent of HIVSGD and characterize the infection at the level of DNA and gene expression. If these candidate organisms do not contribute to HIVSGD we will attempt to isolate the agent using representational differential display and then characterize that infection. This study will determine how Epstein-Barr virus manipulates cellular gene expression to result in characteristic phenotypic changes detected in HLP and correlate these molecular findings with clinical parameters determined in the first AIM. The proposed work is multidisciplinary incorporating principles of viral pathogenesis, clinical research design and oral epidemiology. These studies will serve to advance the knowledge of oral herpes viral pathogenesis and will be carried out in collaboration with individuals who are leaders in the aforementioned three areas. Further, involvement in these studies will enhance the candidate's prior training in oral medicine and microbiology while equipping her with tools to perform meaningful studies centered around patient oriented clinical research.