Blind T-cell homeostasis in CD4-deficient mice.

Recently, it has been proposed that normal T-cell count is maintained by a homeostatic mechanism which is "blind" to the distinction between CD4+ T cells and CD8+ T cells. Interest in this blind homeostasis hypothesis (BHH) stems in part from its implications regarding the pathogenesis and treatment of HIV infection. In this report, BHH was tested in CD4-deficient mice. We found that as predicted by BHH, despite the absence of CD4+ T cells, CD4-deficient mice maintain normal absolute T-cell counts in the blood and spleen primarily through a marked increase in CD8+ T cells. These findings provide strong new support for BHH.