People with HIV and lymphoma who undergo stem cell transplants appear to have no worse degree of immune impairment and recovery than HIV-negative people with lymphoma, according to a study published in the June 15 issue of the journal Clinical Infectious Diseases.

Chemotherapy is a fairly effective treatment for lymphoma, a cancer of the immune system's cells. However, a significant number of people with the disease do not respond to chemotherapy, or they relapse after treatment. In these instances, the only other option is a stem cell transplant. Unfortunately, this procedure carries significant risks, as a person's immune system must be essentially wiped out with toxic chemotherapy to make space for the new stem cells to grow a more functional—and cancer-free—immune system. This leaves people without a fully functioning immune system for months after the procedure. A concern for HIV-positive individuals who must undergo stem cell transplants is whether they experience worse immune suppression during and after the transplant, and whether the procedure might elevate HIV replication.

To test this theory, Cecilia Simonelli, MD, and her colleagues from the National Cancer Institute in Aviano, Italy, compared immune cell levels in 24 HIV-positive and 9 HIV-negative people before, during and after stem cell transplantation. Of the HIV-positive study participants, 18 had high-grade non-Hodgkin's lymphoma and 6 had Hodgkin's lymphoma. Simonelli's team also monitored virus levels at all time points in the HIV-positive participants.

Participants with HIV started off with lower CD4 counts than the HIV-negative participants, and this difference remained throughout the study's two-year course. However, Simonelli and her colleagues found that the overall trend in CD4 recovery was similar, with both groups seeing roughly the same degree of immune recovery by 24 months after the transplant procedure. People with HIV did exhibit a temporary setback in CD4 recovery three months post-transplant, but they caught up to the HIV-negative cohort by the sixth month. Also, virus levels in the HIV-positive participants remained steadily under control throughout the study's course.

Simonelli's team also found that people with HIV were more likely to develop other infections in the first few months after the transplant than the HIV-negative group, possibly because of the temporary setback in CD4 recovery that was observed at the three-month mark. As a result, the authors encourage using preventive treatment for these other types of infections in people with HIV during the early months post-transplant.

The authors acknowledge that nearly all participants had very well controlled HIV levels, through ARV therapy, at the study's initiation. Therefore, it is possible that people without effective HIV treatment options might have worse outcomes. Nevertheless, the researchers conclude that their results are quite encouraging for people with HIV and lymphoma, and they suggest studying experimental agents such as interleukin-2 and interleukin-7 after transplantation to hasten CD4 recovery.