HIV-associated non-Hodgkin's lymphomas

HIV-mediated B-lymphocyte activation and lymphomagenesis

Non-Hodgkin's (1ii)lymphoma is an AIDS-defining event in a significant percent of U.S. patients infected with the human immunodeficiency virus (HIV). Advances in anti-retroviral treatment and management of opportunistic infection have been accompanied by an increase in the incidence of these lymphomas. In the immunocompromised state of patients late in the course of HIV infection, these lymphomas represent a complication of HIV infection that is associated with an extremely poor prognosis. Currently, there is little understanding of the pathogenesis of HIV-associated lymphomas, which are nearly exclusively of B-cell origin. Experimental data do not support HIV infection in these lymphomas. While some lymphomas show evidence of EBV infection, the majority do not. Polyclonal B-cell hyperactivity during the early phases of HIV infection argues that chronic B-cell stimulation may be the major process predisposing B-cells in the HIV-infected individual to malignant transformation. The mechanism of this stimulation of normal B cells and its relationship to AIDS-associated lymphomas remain poorly understood. In this review, we will summarize current information on HIV-associated B lymphoma and then discuss our views on the association and regulation of HIV-related hyperactivity on the pathogenesis of this lymphoma.

Radiotherapy of primary central nervous system lymphoma in patients with and without human immunodeficiency virus. Ten years of treatment experience at the University of California San Francisco

BACKGROUND

Classic human immunodeficiency virus (HIV) negative primary central nervous system lymphoma (PCNSL) is a relatively uncommon occurrence, whereas the incidence of HIV positive PCNSL has increased dramatically during the past 5 years. Between 2% and 6% of all patients with acquired immune deficiency syndrome (AIDS) will have PCNSL develop clinically, and as many as 11% will have PCNSL found at autopsy. In the United States, some of the earliest and most extensive experience with HIV positive PCNSL has occurred in San Francisco. This article reports on PCNSL in patients with and without HIV.

METHODS

Using our diagnosis-based computer retrieval system, we identified all patients treated with radiotherapy for PCNSL between January 1982 and January 1992 and reviewed their medical records. Population characteristics, risk factors and length of survival (LOS), were analyzed. Statistical methodology included the Cox proportional hazards model and Kaplan-Meier survival curves.

RESULTS

Fifty-six patients were identified with PCNSL, of which 41 were HIV positive and 15 were HIV negative. There was a fourfold increase in the total number of PCNSL cases during the time period 1987-1991 as compared with the preceding 5 years; these cases primarily were in the HIV positive group. The average Karnofsky performance score (KPS) in the HIV positive group was 50, whereas in the HIV negative group, the KPS was 35. However, the median LOS in the HIV positive group was 3 months, whereas in the HIV negative group it was 20 months. Within each group, there was a statistically significant correlation between KPS and LOS.

CONCLUSIONS

Patients with HIV and PCNSL have a much shorter median LOS than do patients with PCNSL but without HIV; however, the outcome for both groups is dismal. Randomized clinical trials are needed to determine which patients with HIV might benefit from more aggressive therapy and to determine the optimal choice and dosages of chemoradiation therapy for patients with PCNSL without HIV.

Heterogeneity of acute lymphoblastic leukemia in HIV-seropositive patients

BACKGROUND

As opposed to large-cell or Burkitt's-type non-Hodgkin's lymphoma, acute lymphoblastic leukemia (ALL) is rarely observed in HIV-seropositive patients and is not a criteria of AIDS in the 1986 classification established by the C.D.C. Furthermore, the few cases of ALL reported so far were B-cell ALL, Burkitt's-type.

DESIGN

We recently observed, with unexpected frequency, ALL cases in this setting: over a 5-year period, 5 of 25 HIV-positive patients referred to our center for hematological malignancies, had ALL. Three patients, who had previously been asymptomatic with regard to HIV infection, had typical Burkitt's-type ALL. Complete remission was achieved in all cases with high-dose lymphoma-type chemotherapy regimens, but 2 patients relapsed 3 and 27 months after diagnosis. Their clinical characteristics and outcome are discussed with reference to the cases reported thus far in the literature. One patient had common early pre-B ALL with the Philadelphia chromosome, and one had a T-cell ALL with an unusual CD7+, CD4-, CD8- phenotype. Prognosis was very poor in both cases.

CONCLUSION

The exact incidence and the therapeutic management of B-cell ALL in HIV-positive patients warrants further evaluation. In addition, we show that there may be a heterogeneity among ALL cases in this setting, with the first description of 2 non-Burkitt's ALL with atypical features in HIV-positive patients.