Researchers at the University of California, San Francisco, have identified HIV-infected macrophages that are associated with more than half of AIDS-related lymphoma (ARL) in the post-highly active antiretroviral therapy (HAART) era, according to findings presented at the American Association for Cancer Research 101st Annual Meeting 2010.

"The frequency of this type of tumour is double that from the pre-HAART era and it is present in all subtypes of lymphoma," said Leanne C. Huysentruyt, Ph.D, assistant research scientist at the University of California, San Francisco.

The risk of developing non-Hodgkin lymphoma is 60 times greater in patients with HIV, despite the initiation of HAART - an aggressive treatment regimen of at least three anti-retroviral drugs that attack different parts of HIV to suppress viral replication.

Using specimen data from the AIDS and Cancer Specimen Resource (from 1982 to 2007), Huysentruyt and colleagues investigated the incidence of HIV-infected lymphomas in the pre- and post-HAART eras to determine if HIV-positive lymphomas have a specific immunophenotype.

In the current study, the researchers evaluated tissue microarrays containing more than 150 ARLs for the presence of HIV.

"In the case of cells already infected, such as macrophage viral reservoirs, HAART has little or no effect. This suggests that HIV-infected macrophages in ARLs must be relatively long-lived and unaffected by anti-retroviral therapy," she said. "Therefore, targeting HIV-infected macrophages for drug development may be an effective adjunct to current anti-lymphoma therapies."

The frequency of the Epstein-Barr virus, another cancer-causing virus of the herpes family that was previously associated with ARL, did not change after the introduction of HAART.

Source: The American Association for Cancer Research