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AIDS drugs release trapped immune cells

点击量:   时间:2017-06-14 01:02:09

By Michael Day DURING HIV infection, white blood cells become trapped in lymph nodes and other inflamed tissue rather than being destroyed, a new report argues. This suggests that the immune systems of people undergoing drug therapy could recover more fully than scientists had believed. Previously, many researchers thought that HIV infection leads to the wholesale destruction of the CD4 white blood cells that orchestrate the immune system, and that to fight back, the body has to grow new ones. But when Frank Miedema at the Central Laboratory of the Netherlands, Amsterdam, and his colleagues measured the rate at which CD4 cells reappear in patients’ blood after aggressive anti-HIV therapy, their return was unexpectedly rapid. Miedema says this could be explained only by the release of existing cells from tissues, not by the production of new ones. He suggests in this month’s Nature Medicine (vol 4, p 208) that the redistribution of cells occurs because of an imbalance of immune-regulating chemicals called cytokines after HIV infection. These results, along with those of a T-cell study by French researchers in the same issue (p 215), “provide the final nails in the coffin” of the idea that T cells vanish because of the death of HIV-infected cells, says Mario Roederer of Stanford University, California, in an accompanying article. “These results suggest that people on drug therapy, even those with very low CD4 counts, may see their counts rise steadily over a period of years,” says Andrew McMichael,