Varicella zoster virus encephalitis in an immunocompetent woman

Abstract

cell-to-cell transmission and fusion of infected cells. The gB glycoprotein is an important target for both humoral and cellular immune responses and included in the HCMV vaccine development. HCMV gB gene is classified into four genotypes; namely genotype 1, 2, 3 and 4. All gB genotypes were implicated in the disease severity of transplant recipients and HIV infected patients.Aim: To analyse the gene profile and construct the phylogenetic tree of HCMV gB gene sequences obtained from HIV infected patients who were experiencing HCMV viraemia to document the circulating HCMV gB genotypes in South Africa.Methods & Materials: Nested PCR method targeting variable region of gB gene was developed and gB gene sequences were amplified from twenty archived plasma samples of HCMV viraemic HIV infected patients. Analysis of nucleotide sequences were performed by using Chromas-Pro software programme and phylogenetic tree was constructed by comparing with standard sequences from Genbank, NCBI.Results: The gB2 genotype was detected in 35% (7/20) of patients and only 15% (3/20) represents gB1. The gB3 and gB4 genotypes were identified among 20% (4/20) and 30% (6/20) of patients respectively. All gB gene sequences obtained from study participants displayed 98%-100% similarity with laboratory strains AD 169 and Towne as well as other reference sequences obtained from clinical cases. All participants were severely immunosuppressed and their mean CD4+ T-cell counts was 32 cells/l. Conclusion:All four gB genotypes circulate in the study population and gB 2 genotype is a dominant genotype. High sequence similarity between study samples and vaccine strain indicates that our population will have positive response should the HCMV gB vaccine becomes available in South Africa.