I PEL and all cases of CD- PEL. The efficacy of rituximab in CD- PEL may be due to the ability of this antibody to kill non-malignant CD+ 20 lymphocytes and thereby their potential to promote the disease. A National Cancer Institute-sponsored clinical study is in its recruiting phase to study the efficacy of DA-EPOCH (which includes rituximab) plus lenalidomide in treating PEL. Current studies are also examining the effects of drug-based inhibition of the signaling pathways that are overactive in the malignant plasmablasts in PEL (see Pathophysiology section) for their therapeutic effectiveness. History PEL was first described in 1989 as a malignant B cell-derived non-Hodgkin lymphoma that developed in three individuals afflicted with HIV/AIDS. In 1995, a group of researchers found DNA sequences that identified KSHV/HHV8 sequences in 8 lymphomas in the malignant cells of patients infected with the HIV; all 8 patients had effusions containing malignant cells in their pleural, pericardial, or peritoneal spaces and had malignant cells in their effusions that evidenced the Epstein-Barr viral genome. Nadir and colleagues termed this syndrome of findings pulmonary effusion lymphoma in 1996. During the years following these initial reports, several cases of PEL were found to be KSHV/HHV8-negative, i.e. occurring in individuals with no evidence of being infected with KSHV/HHV8, or to be manifested by solid tumors that were not associated with effusions, i.e. cases of extracavitary PEL. See also List of hematologic conditions References External links Lymphoma Epstein–Barr virus–associated diseases Infectious causes of cancer