Therapy can’t restore CD4 diversity
In another argument for early therapy, researchers at the National Institute of Allergy and Infectious Diseases have shown that CD4 cells decline in overall size during the course of HIV disease and become progressively less diverse.
Moreover, the depletion of cell types may not be immediately restored by therapies such as antiretroviral drugs or interleukin-2.
Publishing their findings in the May issue of Nature Medicine, the researchers note that results argue for treatment early in disease before elements of the immune systems are significantly depleted.
"Our data also suggest that drugs to prevent opportunistic infections may remain important even for patients with CD4 cell counts that are rapidly increasing in response to therapy, because these individuals may be missing part of their CD4 repertoires," said H. Clifford Lane, MD, NIAID’s clinical director.
Added co-author Mark Connors, MD, also a NIAID AIDS researcher:
"The loss of CD4 cells is a qualitative phenomenon as well as a qualitative one. In other words, a CD4 cell count of 200 during the natural history of HIV infection may be very different from a CD4 cell count of 200 in the context of therapy. Depletions in the CD4 cell repertoires of HIV-infected persons and hence the reduced ability of their immune systems to recognize certain antigens are probably key to the development of immunodeficiency in these people."