Determination of Frequency of Epstein-Barr Virus in Non-Hodgkin Lymphomas Using EBV Latent Membrane Protein 1 (EBV-LMP1) Immunohistochemical Staining

Background: The presence of Epstein-Barr virus (EBV) in Non-Hodgkin’s lymphoma can be identified byimmunohistochemistry for detection of EBV latent membrane protein (LMP). The role of EBV as an etiologic agentin the development of non-Hodgkin lymphoma has been supported by detection of high levels of latent membraneprotein 1 (LMP-1) expression in tumors. However, no study has been conducted in a Pakistani population up tillnow to determine the frequency of Epstein-Barr virus positivity. The objective of our study was to determine avalue for non-Hodgkin lymphoma patients using EBV LMP-1 immunostaining in our institution. Materials and
Methods: This study was carried out at the Department of Histopathology, Armed Forces Institute of Pathology(AFIP), Pakistan from December 2011 to December 2012. It was a cross sectional study. A total of 71 patientswho were diagnosed with various subtypes of NHL after histological and EBV LMP-1 immunohistochemicalevaluation were studied. Sampling technique was non-probability purposive. Statistical analysis was achievedusing SPSS version 17.0. Mean and SD were calculated for quantitative variables like patient age. Frequenciesand percentages were calculated for qualitative variables like subgroup of NHL, results outcome of IHC forEBV and gender distribution.
Results: Mean age of the patients was 53.6±16 years (Mean±SD). A total of 50(70.4%) were male and 21 (29.6%) were female. Some 9 (12.7%) out of 71 cases were positive for EBV–LMP-1immunostaining, 2 (22.2%) follicular lymphoma cases, 1 (11.1%) case of T-cell lymphoblastic lymphoma, 4 (44.4%)cases of diffuse large B cell lymphomas, 1 (11.1%) mantle cell lymphoma and 1 (11.1%) angioimmunoblastic Tcell lymphoma case.
Conclusion: In our study, frequency of EBV in NHL is 12.7% and is mostly seen in diffuselarge B cell lymphoma. This requires further evaluation to find out whether this positivity is due to co-infectionor has a role in pathogenesis.