POSTTRANSPLANTATION LYMPHOPROLIFERATIVE DISORDERS IN MEXICO - AN AGGRESSIVE CLONAL DISEASE-ASSOCIATED WITH EPSTEIN-BARR-VIRUS TYPE-A

Post-transplantation lymphoproliferative disorders (PT-LPDs) are a com plication of immunosuppression with variable clinical behavior and fre quent Epstein-Barr virus (EBV) association, There is geographic variat ion in the association of EBV with certain tumors and a lack of studie s of PT-LPDs from developing countries, so we decided to study in deta il a series of PT-LPDs from Mexico to identify similarities and differ ences between populations in Mexico and those in Europe and the United States. We used paraffin-embedded tissue from eight PT-LPDs (six from men, two from women) that arose after renal transplantation. Clinical data, morphologic features, and clonality on the basis of immunoglobu lin (Ig) light chain restriction, as well as polymerase chain reaction (PCR) for Ig heavy chain genes, were studied. The presence of EBV was investigated with PCR, immunohistochemical analysis for latent membra ne protein (LMP)-1, and in situ hybridization for EBV early RNA transc ripts, In addition, the subtype of EBV based on the EBNA 2A and 2B gen es and the presence of a 30-bp deletion in the LMP-1 gene were investi gated by PCR, Seven (87.5%) of eight cases presented with gastrointest inal involvement; five patients died. Three cases were polymorphic PT- LPDs, four were monomorphic large cell lymphomas (one diffuse large ce ll, three immunoblastic), and one was unclassifiable, All showed a B-c ell phenotype, with a clonal population demonstrated in seven of the e ight cases. Tumor cells expressed EBERs in all of the cases and LMP-1 in six of seven evaluable cases. Seven of seven cases showed EBV subty pe A. Two (25%) of eight cases had the 30-bp LMP-1 deletion, This stud y shows that PT-LPDs in Mexico are clonal disorders associated with EB V subtype A. In contrast to series from Europe and the United States, our cases showed a significantly higher incidence of gastrointestinal tract involvement (P < .001), and a lower incidence of the 30-bp LMP-1 deletion, although this was not statistically significant (P < .28).