According to a recent article published in the journal Blood, research suggests that autologous stem cell transplantation (ASCT) may be feasible in patients with HIV (human immunodeficiency virus) associated lymphoma.
Non-Hodgkin’s lymphoma is a cancer of the lymph tissue, which is part of the immune system in the body. Lymph tissue is present in lymph nodes, lymph vessels and bone marrow, which exist throughout the body. It is also present in organs such as the thymus, tonsils and spleen. The main cells in the lymph system are lymphocytes, of which there are two types: B and T-cells. Each of these cells has a very specific function in aiding the body to fight infection. The large majority of NHL cases involve cancer of the B-lymphocytes, characterized by the excessive multiplication of these atypical cells. These cancerous cells can crowd lymph tissue causing suppression of normal formation and function of other cells normally found in this tissue. Because lymphocytes can travel virtually anywhere in the body through blood or lymph fluid, lymphomas can occur in sites other than lymph tissue, such as the gastrointestinal tract or the brain.
Individuals with HIV have an estimated 150 to 250-fold higher risk of developing non-Hodgkin's lymphoma (NHL) compared to individuals without the virus. Because HIV weakens the immune (infection fighting) system of the body, NHL treatment has not been aggressive and is associated with a poor prognosis. Recently, however, researchers have reported that the use of intensive anti-viral therapy (HAART) allows standard, higher doses of chemotherapy to be tolerated in individuals with HIV related NHL, which may increase survival rates. Patients with HIV related NHL often have fast-growing, or high-grade lymphomas that tend to develop outside of the lymph system. Previous analyses have indicated that aggressive anti-viral therapy, or HAART, has improved immune function in HIV-infected individuals and has improved survival in patients with AIDS-related lymphoma (ARL).
Since HAART has improved immune function in HIV-infected individuals and has made higher doses of chemotherapy feasible for HIV lymphomas, researchers have been investigating the feasibility of ASCT for HIV-L. High-dose chemotherapy kills more cancer cells than moderate doses of chemotherapy. However, more healthy cells, including stem cells, are also killed due to the high doses, often causing significant side effects. Stem cells are immature blood cells produced in the bone marrow that mature into red blood cells, which carry oxygen to tissues; white blood cells, which fight infection; and platelets, which aid the blood in clotting. Autologous stem cell transplants involve the collection of patient’s stem cells prior to treatment and re-infusion following high-dose therapy to restore depleted blood cell levels.
Researchers in a multi-center study recently conducted a small clinical trial evaluating the efficacy and feasibility of ASCT for HIV-L. Nine patients with HIV-L on HAART with no detectable HIV virus loads had their stem cells harvested. After high-dose chemotherapy, all nine patients underwent ASCT and there was successful integration of the transplant (engraftment). Infectious complications were as expected. Two patients relapsed and died. At an average of 19 months after transplantation, seven patients remain in remission.
From this small study, results seem to indicate that ASCT may be feasible for the treatment of HIV-L. Future studies are warranted to further determine the efficacy and feasibility of ASCT for the treatment of HIV-L. Patients with HIV-L may wish to speak with their physician about the risks and benefits of participating in a clinical trial evaluating the feasibility or efficacy of ASCT or other novel therapeutic approaches. Two sources of information regarding ongoing clinical trials include comprehensive, easy-to-use listing services provided by the National Cancer Institute (cancer.gov) and www.eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients. (Blood, Vol 98, No 13, pp 3857-3859, 2001)