Prevalence of epstein barr virus in malignant lymphomas in Iraq

Abstract

Malignant lymphomas are among the common tumors that are associated with and may complicateEpstein Barr Virus (EBV) infection. Although the strongest association is with the endemic Burkittlymphomas (BL), the trend of association with sporadic lymhpomas reveals a consistently increasingprevalence of the virus in Hodgkin’s disease (HD) in recent years compared to the non-Hodgkin type(NHL) which may point to a possible role for the virus in the predisposition and etio-pathogenesis ofthe disease.evaluate the association of EBV with Hodgkin’s and non-Hodgkin lymphomas in relation to age, sexand HD subtype retrospectively using archival tissue biopsy sections.Method: EBV was detected by In Situ Hybridization (ISH) using EBERs RNA probes in paraffinembeddedtissue sections prepared from archival tissue biopsy blocks.(a) EBV was detected in 25 of 40 HD cases (62.5%), 9 of 30 (30%) NHL cases, 4 of 10 (40%) BLcases, and in 5 of 20 (25%) other (non-BL) NHL cases. (b) Among the EBV-positive HD cases, 19(76%) were of the mixed cellularity (MC) subtype, 1 (4%) of the Nodular Sclerosis (NS) subtype, 1(4%) of the Lymphocyte Predominance (LP) subtype and 4 (16%) cases were of the LymphocyteDepletion (LD) subtype. (c) Age distribution of HD cases revealed a bi-modal pattern characterized byan early major peak (67.5% of cases) below 35 years and a minor peak (32.5% of cases) above the ageof 40. On the contrary, NHL cases revealed a nearly even age distribution (43.3% versus 56.6%)below and above the age of 40, respectively. (d) No difference was observed in the incidence of HDbetween males and females where the ratio was close to 1:1. On the other hand, a slight malepredominance was seen among NHL cases with a male to female ratio of 2:1.(a) the prevalence rate of EBV infection was high among HD cases and fell within the prevalence ratesfound in previous similar studies revealing a range of values from 20 to 90%. (b) the higher prevalenceof EBV positivity in HD compared to NHL found in this study points to a more substantial role forthe virus in the pathogenesis of former compared to the latter disease which also comes in agreementwith the greater environmental element compared to the genetic element in the etiology of HD. (c) Theunexpected high EBV positivity in the LD subtype of HD may be interpreted as result of theprogression of some of the early less aggressive MC-HD cases to the advanced more aggressive LDHDsubtype. (d) the bi-modal age distribution of EBV-positive HD cases follows the same pattern ofdistribution of the disease in general and testifies for the influence of environmental factors in theincidence of the disease.