A small pilot study of newly HIV infected, treatment-naive heroin users found that their CD4s dropped faster if they used heroin intermittently rather than continually, The New York Times reports. Publishing their findings in AIDS and Behavior, investigators researched 77 individuals who were taking part in a 2010 study of HIV-positive alcoholics, asking about their drug use over the previous 30 days at the study’s outset, the six-month mark and at the end of a year.

The 39 participants who reported no heroin use had a mean CD4 decrease of 10 cells after one year, while the 21 people who reported intermittent use had a mean CD4 decrease of 103 cells. Strangely, the 17 who reported persistent heroin use had a mean CD4 increase of 53 cells.

The researchers theorize that one possible reason for the difference in CD4 decreases is that people who cannot afford a consistent supply of heroin also do not have enough money for food, and that starvation suppressed the immune system of those shooting up intermittently. It is also possible that repeated cycles of withdrawal chipped away at CD4 cell levels among those shooting up intermittently.

The study’s findings were in line with a 2006 study of morphine-addicted primates. Those who were taken off morphine and subjected to withdrawal experienced greater immune damage than those who remained on the drug.

To read the New York Times story, click here.

To read the study abstract, click here.