The human γ-herpes virus- 8 (HHV-8) was first described in AIDS- related Kaposi’ s sarcoma (KS) tumour samples. In this study, we report comparative studies on paraffin-embedded biopsies of AIDS-related KS (AKS) and endemic KS (EKS)with regard to HHV-8 content as evaluated using polymerase chain reaction (PCR) and immunohistochemistry. DNA was extracted either using Chelex-100 or using Qia- gene kit and was evaluated with the help of a semiquantitative PCR assay. The PCR detection of HHV- 8 was more sensitive to the Chelex method than to Qia- gene. The threshold for PCR test sensitivity with the help of serial dilution of DNA was at the level of five plasmid ORF-26 regions, and DNA from 25 body cavity-based lymphoma- 1 cells. The results expressed as virus load/actin unit showed progressively higher HHV-8 levels in late (nodular) cases, compared to those in early (patch/plaque)stages. Evaluation of HHV- 8 DNA levels in tumour tissues, thus, indicates a correlation between virus load and KS stage. Double immunostaining of spindle cells(SC)inKSbiopsiesfor CD34 and HHV-8/latency- associated nuclear antigen (LANA)showed an increase in double- positive SC in the lesions of nodular AKS and EKS cases, compared to that in plaque and- patch stages. However, 10- 15% of CD34+ /LANA SC cells were observed during the development from patch to nodular casesofAKSand EKS.Our results indicate that PCR analysis is a simple and sensitive diagnostic method for HHV-8 evaluation in KS tissues, processed for conventional histopathology.
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