Public health officials are concerned that use of crystal methamphetamine may contribute to high-risk sexual behavior leading to HIV transmission, but the drug's effects on immune function and HIV disease progression are not well understood.

At the 4th International AIDS Society Conference on HIV Treatment, Pathogenesis and Prevention, held last week in Sydney, Australia, researchers presented data from a pilot study to describe HIV disease parameters associated with methamphetamine use in an observational study in San Francisco.

The analysis included 28 HIV positive adults seen at an HIV clinic. Methamphetamine use within the past 72 hours was assessed by self-report and urine testing. The investigators measured HIV drug resistance, viral replication capacity, viral tropism (CCR5 or CXCR4 co-receptor use), and clinical markers.

Results

• 19 subjects tested positive and 9 tested negative for recent methamphetamine use.

• Only 3 individuals (2 methamphetamine users and 1 non-user) were receiving antiretroviral therapy.

• Subjects who tested positive for methamphetamine use had a significantly lower mean CD4 cell count than non-users (362 vs 551 cells/mm3; P = 0.003).

• Recent methamphetamine users tended to have higher viral loads (4.38 vs 3.86 log copies/mL; P = 0.18), but this difference did not reach statistical significance.

• HIV from methamphetamine users had greater susceptibility to AZT (Retrovir), but lower susceptibility to emtricitabine (Emtriva).

• HIV from methamphetamine users tended to have a lower replicative capacity (83% vs 113%; P = 0.07).

• 3 methamphetamine users had dual-tropic or mixed-tropic virus compared with none of the non-users (P = 0.24).

• In an adjusted regression model, methamphetamine use independently predicted CD4 cell count, but neither viral load, patient age, nor viral tropism did so.

Conclusions

In our study [recent methamphetamine users] had lower CD4+ T-cell counts, an effect independent of viral load," the researchers concluded. "We detected differences in drug susceptibility and trends towards higher viral loads, dual/mixed tropism, and lower replicative capacity in [recent methamphetamine users]."

They added that, "While it is possible that HIV+ persons who use methamphetamine may have remained off antiretrovirals for greater periods of time resulting in lower CD4+ [cell] counts, additional studies are needed to confirm whether methamphetamine use may modulate CD4+ levels."

University of California, San Francisco, CA: San Francisco Department of Public Health, San Francisco, CA; Monogram Biosciences, South San Francisco, CA

07/31/07

Reference
J Barbour, S Philip, A Cohen, and others. Methamphetamine using HIV-1+ adults have lower CD4+ T cell counts than HIV-1+ adults who do not use Methamphetamines. 4th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention. Sydney, Australia, July 22-25, 2007. Abstract MOPEB095.

4th IAS
Main Conference Page