Diffuse large B-cell lymphoma

Abstract

Systemic (or "non-CNS") diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma accounting for approximately 30-40 % of all new lymphoma diagnoses in HIV-negative patients and 30-80 % in HIV-infected patients. Both plasmablastic lymphoma and primary CNS lymphoma are considered variants of DLBCL, but will be discussed in detail in separate chapters (Chaps. 5, Plasmablastic Lymphoma; and Chap. 7, Primary CNS Lymphoma). While in the era before 1996, when no combination antiretroviral therapy (cART) was available, the risk of developing an aggressive non-Hodgkin lymphoma (NHL) was up to 600-fold increased compared to immunocompetent patients; this risk has declined to <20-fold in the era of cART. In DLBCL in HIV-infected patients the severity of immunosuppression is the most important risk factor for developing disease. The median CD4 count at DLBCL diagnosis is typically around 200 cells/ml. Low CD4 nadir, the length of impaired immune function secondary to low CD4 counts, and length of time of HIV viremia, even at low levels, appear to be important risk factors for developing DLBCL.