Current, not nadir CD4 cell count predicts risk of lymphoma in HAART era

Current and not nadir CD4 cell count is associated with an HIV-positive individual’s risk of developing lymphoma in the HAART era, according to data presented to the Eleventh Annual Conference of the British HIV Association in Dublin on April 21^st.

Since effective anti-HIV therapy became available, the incidence of lymphoma amongst HIV-positive individuals has declined, but not as steeply as the AIDS-defining malignancy Kaposi’s sarcoma or other opportunistic infections.

It has been suggested that extensive immune damage before the initiation of HAART may increase a patient’s risk of subsequently developing a lymphoma, even if anti-HIV therapy successfully suppresses HIV replication and improves immune function.

Investigators from the UKCHIC cohort study therefore examined the associations between lymphoma and sex, HIV risk category, ethnicity, viral load, nadir and current CD4 cell count, and the use of HAART.

Data were collected from 1996 onwards. Of the 13,800 patients included in the investigators’ analysis, 106 developed a lymphoma. The overwhelming majority of these individuals were gay men (75%) and white (72%). At the time the lymphoma was diagnosed, patients had a median age of 38 years, the median CD4 cell count was 169 cells/mm³, and 49% were taking HAART.

Compared to individuals who had a current CD4 cell count above 500 cells cells/mm³, the risk of lymphoma was highest in patients with a CD4 cell count below 50 cells/mm³ (relative rate 9.46; p = 0.001). The risk of developing a lymphoma decreased as current CD4 cell count increased.

When the investigators included all variables in their model, including sex, ethnicity, age, previous use of antiretroviral therapy, viral load and nadir CD4 cell count, they found that the only variable significantly associated with the risk of developing lymphoma was current CD4 cell count.