A known suppression factor in the immune system increases in HIV-infected individuals on critical immune cells, reports a study in the November 2007 issue of Nature Immunology. Key targets of HIV infection, CD4+ T cells show elevated levels of the suppression factor and are associated with rapid HIV disease progression.
Bruce Walker and colleagues evaluated HIV-positive people who progressed relatively fast to disease and found significant increases in CTLA-4 expression on CD4+ T lymphocytes compared to those who did not-- so-called 'long-term non-progressors'. The team also compared CTLA-4 expression on CD4+ T cells in people before and after receiving highly active anti-retroviral therapy and found higher T cell-associated CTLA-4 in those who were off therapy. Importantly, the team found that blocking the activity of CTLA-4 improved immune function.
These results suggest that decreasing CTLA-4 expression on CD4+ T cells may provide a potential therapy to improve lymphocyte function in HIV-infected individuals.
Bruce Walker (Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA)
Abstract available online.
(C) Nature Immunology press release.
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