LATENT VARICELLA-ZOSTER VIRUS IS LOCATED PREDOMINANTLY IN NEURONS IN HUMAN TRIGEMINAL GANGLIA

Varicella-zoster virus (VZV) is a human herpesvirus that causes varice lla (chicken pox) as a primary infection and, after a variable period of latency in trigeminal and dorsal root ganglia, reactivates to cause herpes tester (shingles). Both of these conditions may be followed by a variety of neurological complications, especially in immunocompromi sed individuals such as those with human immunodeficiency, virus (HIV) infection. There have been a number of conflicting reports regarding the cellular location of latent VZV within human ganglia. To address t his controversy we examined fixed wax-embedded trigeminal ganglia from 30 individuals obtained at autopsy, including 11 with HIV infection, 2 neonates, and 17 immunocompetent individuals, for the presence of la tent VZV. Polymerase chain reaction (PCR), in situ hybridization, and PCR in situ amplification techniques with oligonucleotide probes and p rimer sequences to VZV genes 18, 21, 29, and 63 were used. VZV DNA in ganglia was detected in 15 individuals by using PCR alone, and in 12 i ndividuals (6 normal non-HIV and 6 positive HIV individuals, but not n eonatal ganglia) by using PCR in situ amplification. When in situ hybr idization alone was used, 5 HIV-positive individuals and only 1 non-HI V individual showed VZV nucleic acid signals in ganglia. In all of the VZV-positive ganglia examined, VZV nucleic acid was detected in neuro nal nuclei. Only occasional nonneuronal cells contained VZV DNA. We co nclude from these studies that the neuron is the predominant site of l atent VZV in human trigeminal ganglia.