Etiology and pathogenesis of AIDS-related non-Hodgkin's lymphoma

The incidence of non-Hodgkin's lymphoma (NHL) is greatly increased in HIV-infected individuals; malignant lymphoma is the second most common neoplasm that occurs in association with AIDS. The vast majority of neoplasms are clinically aggressive, monoclonal B-cell neoplasms that exhibit Burkitt's, immunoblastic, large cell, or transitional histopathology. Approximately 80% arise systemically (nodal or extranodal) and 20% arise as primary CNS lymphomas. A small proportion of neoplasms are body cavity-based, primary effusion lymphomas that are uniquely associated with Kaposi's sarcoma-associated herpesvirus infection. Recently, HIV-associated polymorphic lymphoproliferative disorders have been described as well. AIDS-related NHLs appear to exhibit distinctive clinical characteristics according to their histopathology and anatomic site of origin. These findings suggest that more than one pathogenetic mechanism is operational in the development and progression of AIDS-related NHLs. Further work is necessary to develop a complete understanding of the etiology and pathogenesis of NHL in the setting of HIV infection. AIDS-related NHL is an important biologic model for investigating the development and progression of high-grade NHLs and NHLs that develop in immune-deficient hosts.