 The development of this variant appears due, at least in part, to immunosenescence, i.e.the immunodeficiency occurring in old age.A study by Green and Eversole published in 1989 reported on 9 individuals afflicted with HIV/AIDS who 
presented with lymphomatous masses in the oral cavity; these lymphomas were populated by apparently malignant Epstein-Barr virus-infected plasmablasts that did not express T-cell lymphocyte marker proteins.