PRIMARY NON-HODGKINS-LYMPHOMA OF THE INTESTINE - HIGH PREVALENCE OF EPSTEIN-BARR-VIRUS IN MEXICAN LYMPHOMAS AS COMPARED WITH EUROPEAN CASES

Recent studies in Western European populations have shown that periphe ral T-cell non-Hodgkin's lymphomas (T-NHLs) are associated with Epstei n-Barr virus (EBV) in a higher percentage than sporadic B-cell NHL (B- NHLs), and that the frequency of EBV-positivity might be influenced by the primary site of the tumor. Because of the geographic differences in EBV expression in Burkitt's lymphoma (BL) and Hodgkin's disease (HD ), and the lack of studies of sporadic NHL from developing countries, we decided to survey the presence of EBV in a series of primary intest inal lymphomas from patients in Mexico and in Western Europe, and to a nalyze whether EBV status is influenced by tumor phenotype, and geogra phic or ethnic determinants. Paraffin-embedded tissue from 43 primary intestinal NHLs (19 cases from Mexico and 24 from Western Europe) were examined, including 17 high grade B-NHLs, 9 low grade B-NHLs, and 17 T-NHLs; 6 of which were enteropathy associated T-cell lymphomas. The d istribution of histologic subtypes was similar in both groups. The pre sence of EBV was investigated with a combined approach using a nested polymerase chain reaction technique as well as immunohistochemistry fo r latent membrane protein-1 and in situ hybridization for EBV early RN A transcripts (EBER 1/2) RNAs. The median age of the Mexican patients was significantly lower than the median age of the European patients ( 32 v 62 years). This difference was most pronounced in patients with T -cell lymphoma (24 v 63 years). EBER-positive tumor cells were detecte d in 13 of the 43 (30%) cases of primary intestinal lymphoma, includin g 5 of 26 sporadic B-NHL (3 high grade and 2 low grade), and 8 of 17 T -NHL, all of which were classified as pleomorphic, medium and large ce ll. The rates of EBV-positivity were markedly different for European a nd Mexican cases. Whereas 7 of 7 (100%) T-NHL and 5 of 12 (42%) sporad ic B-NHL of Mexican origin were EBER-positive, only 1 of 10 T-NHL and 0 of 14 sporadic B-NHL from Europe showed EBER expression in tumor cel ls. Latent membrane protein was positive in only 2 of 43 cases, 1 of w hich was an EBER-negative high grade B-NHL from Mexico that showed int act total mRNA in control hybridization. CD30 expression was found in 4 of 8 EBV-positive T-NHL and in none of the EBV-positive B-NHL. In co ntrast to European cases, intestinal NHLs from Mexico show a very high frequency of EBV-positivity, which is not limited to T-NHL, but inclu des a significant proportion of B-NHL. This study strongly suggests th at similar to HD and probably BL, there are important epidemiologic di fferences in EBV association in intestinal T-cell NHL between European and Mexican populations. These differences might be the result of env ironmental factors, for example, earlier contact with childhood viruse s on intestinal lymphomagenesis. (C) 1997 by The American Society of H ematology.