 to have no apparent defect in their immune system.The malignant plasmablasts in more than half the cases of PBL are infected with a potentially cancer-causing virus, Epstein Barr virus (EBV), and rare cases of PBL appear due to the plasmablastic transformation of a preexisting low-grade B-cell lymphoma.One variant of PBL, sometimes termed plasmablastic lymphoma of the elderly, has a significantly better prognosis than most other cases of PBL.