Many a protease Lazarus can tell you that triple-drug combos, when they work, cause CD4-cell counts to rise, even soar. But no one can tell whether the new cells are as good as, well, new. Now a tiny French study hints that-mais oui!-the numbers may add up to immune restoration. A team led by Dr. Brigitte Autran counted immune cells over a year in eight patients on protease cocktails and found that so-called naive CD4 cells had regenerated. "This is the first evidence that people who have been on triple-drug therapy for more than a year can make new CD4 cells," said Dr. Donald Mosier, an immunologist at California's Scripps Research Institute. "It's definitely a glimmer of hope."
A bit of background: The immune system has two kinds of CD4 cells-naive and memory. The naive CD4 is like a fighter pilor on a quest for pathogens such as PCP. Once it meets its match, it becomes a memory cell, forever progammed to identify and battle that particular foe. As HIV infection depletes CD4s, memory cells get pitched, along with the immune system's defence against invaders. "In the French study, the actual percentage of naive cells was increasing after about six months of treatment," said the AIDS Treatment Data Network's Richard Jeffreys. Theoretically, these new cells can meet and be programmed to fight any of the range of nasty bugs-from CMV to the common cold.
Although researchers don't yet know if these naive cells function fully, the results seem sunny compared with earlier studies. "They were doing these tests after three months and saying all we have left are memory cells," Jeffires said. "What we find here is that if you follow people longer, you start to see naive cells. For someone coming from a low count, less than 200, this is reason to try to hang in there with treatment." The findings also suggest that the thymus, where CD4 cells are created, may recover faster and better with combo therapy's suppression of HIV.
