Prevalence of Epstein–Barr Virus Genotypes in Pakistani Lymphoma Patients

The Epstein-Barr virus (EBV) is a herpesvirus infecting more than 90% of the human population. The tropism ofEBV for B lymphocytes is evidenced in its association with many lymphoproliferative disorders. Different types of EBV(EBV-1 and EBV-2), classified on the basis of EBV nuclear antigen-2 (EBNA-2) genotyping, have been reported inbenign and malignant pathologies, but there is almost no information about their frequency in the Pakistani population.The aim of this study was to determine the frequency and distribution of EBNA-2-based EBV genotypes in lymphomapatients. Genomic DNA was extracted from formalin-fixed paraffin embedded (FFPE) tissue samples obtained from 73EBV-DNA-positive lymphoma patients. The β-globin gene was amplified to assess the presence and quality of cellularDNA from all samples. EBER-1 DNA was detected by PCR to confirm EBV presence in tissue samples. EBNA-1mRNA relative quantification done by quantitative PCR substantiated EBNA-1 mRNA overexpression in 43.8% ofEBV-positive cases in comparison to EBV-positive control cell line. EBNA-2 genotyping was done by nested PCR.Among typable samples, EBV-1 was found in 90.7% of samples while EBV-2 was present in 9.3% cases. These resultsshow that EBV-1 was the most prevalent type in the lymphoma population of Pakistan. This epidemiology of EBV inPakistani lymphoma patients represents an important first step in using EBV for prognosis and monitoring treatmentresponse.