Sensory and sympathetic ganglia in HIV-1 infection: immunocytochemical demonstration of HIV-1 viral antigens, increased MHC class II antigen expression and mild reactive inflammation.

Sensory and sympathetic ganglia from 12 cases of human immunodeficiency virus type 1 (HIV-1) infection, all but one without clinical evidence of peripheral nerve disease, were studied immunocytochemically for their content of lymphocytes, macrophages, MHC Class II antigens and HIV-1 and cytomegalovirus antigens. They were compared with ganglia from 7 normal and peripheral nerve disease control cases. Compared with normal controls, many of the ganglia from the majority of HIV-1-infected subjects contained more T lymphocytes and macrophages and enhanced MHC class II expression. A few also showed occasional neuronal degeneration which was not present in the normal controls. In 7 cases HIV-1 gp41 envelope protein and/or p24 core protein antigens were detected in intraganglionic macrophages. Sensory ganglia contained more gp41 HIV-1 antigen than sympathetic ganglia. There was no clear correlation between detection of HIV-1 antigens in ganglia and in the CNS. Detection of HIV-1 antigens in ganglia was more common in cases of HIV-1 infection that had progressed to clinical AIDS by the time of death (71%) than in those that had not done so (40%). It is concluded that there is commonly a mild ganglionitis which is asymptomatic in the absence of detailed clinical testing and frequently associated with local presence of HIV-1 antigens in sensory and sympathetic ganglia in AIDS.