Prevalence of Epstein–Barr Virus Genotypes in Pakistani Lymphoma Patients

Abstract

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