EBV infection was detected in 12- 44% of lymphoma tissues that have emerged in patients with RA.[7] It was reported that reactivation of EBV was detected in most patients with MTX-LPDs, and LPDs regressed in half of them after discontinuation of MTX therapy.[11] Immunosuppression induced by MTX may be involved in the reactivation of EBV, which may lead to the development of MTX-LPD.[13] In the present patient, serological tests for EBV-VCA IgG and EBNA were positive, and the test for EBV IgM was negative. This evidence concerns the gene CD40LG and lymphoma.