(Reuters Health) - Increasing CD4 cell counts in HIV/AIDS patients being successfully treated with highly active antiretroviral therapy (HAART) appear to be associated with a greater risk of Hodgkin's Lymphoma (HL), researchers report in the December 1st issue of Blood.
Dr. Alexandra Levine, author of an accompanying editorial, told Reuters Health that in order to thrive, the malignant Reed-Sternberg cells seen in HL "require the presence of CD4 lymphocytes, which surround the malignant cells, and produce cytokines necessary for their growth and survival."
"Unfortunately, the increase in CD4 cells in the era of HAART has now been associated with an increase in the incidence of HL lymphoma among HIV-infected persons," Dr. Levine, of the University of Southern California, Los Angeles, pointed out.
Given that HAART has led to the reduction of various lymphomas and opportunistic infections, lead investigator Dr. Robert J. Biggar added that "it is therefore paradoxical that the risk of HL is actually increasing."
Dr. Biggar and colleagues at the National Institutes of Health, Bethesda, Maryland came to this conclusion after studying HIV/AIDS data from 1980 through 2002.
Overall, the HL incidence in the 4 to 27 months after AIDS onset in the more than 317,000 people studied, was 36.2 per 100,000 person-years. In particular, between 1980 and 1995, the incidence was just over 30 per 100,000 person-years. However, this rose to 49.3 per 100,000 person-years between 1996 and 2002.
The rose in HL incidence was reflected by CD4 cell counts. In subjects with CD4 counts below 50 per microliter, it was 20 per 100,000 person-years. In those with cells counts from 150 to 199, the incidence was 53.7 per 100,000 person-years.
"Understanding how HL is supported by the normal immune cells may help to develop new forms of treatment that will interrupt this tumor-immune cell relationship in HL, whether or not it occurs in the setting of HIV infection," Dr. Biggar concluded.
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