Interaction of HIV and EBV at lymphoid tissue level: immunohistochemistry and in situ hybridization

The presence of Epstein-Barr virus antigens and genome was studied in lymph nodes from HIV + patients affected by PGL. Cryostat sections from 50 lymph nodes of HIV + patients were immunostained with EBV-VCA (viral capsid antigen), EBV-EA (early antigen) and p24 HIV major core protein monoclonal antibodies. In situ hybridization was performed using a biotin conjugated EBV DNA probe; the reaction product was demonstrated by immunohistochemical method. As positive controls, EBV producer B95-8 and HIV infected H9 cell lines were used. The majority of patients had circulating EBV antibodies mainly directed against the viral capsid antigen and only in few cases against early antigens. Positivity for HIV p24 protein was detected in 43 out of 50 lymph nodes within the germinal centers with a reticular pattern. Only 2 out of 50 lymph nodes presented very few positive cells for EBV antigens and none expressed detectable EBV genome. Our results suggest that EBV cellular expression does not correlate with serum positivity; furthermore the absence of EBV antigens and genome at tissue level might indicate that EBV is not directly involved in the pathogenesis of PGL.