HAART Improves Syphilis Serologic Response Rates in HIV Patients

Highly active antiretroviral therapy (HAART) reduces syphilis serological failure rates in patients co-infected with HIV, according to researchers at Johns Hopkins University School of Medicine.

"Given that syphilis serological failures and neurosyphilis occur in patients with more advanced immunosuppression," lead investigator Dr. Khalil G. Ghanem told Reuters Health, "immune reconstitution using highly active antiretroviral therapy appears to be a reasonable additional intervention to try and limit poor outcomes in HIV and syphilis co-infected patients."

Dr. Ghanem and colleagues in Baltimore studied 231 cases of syphilis in 180 HIV-infected patients who were followed for a median of 5.3 years.

Serologic failure was defined as the lack of a 4-fold decrease in rapid plasma reagin titers 9 to 12 months after therapy or a 4-fold increase in titers 30 days after therapy. There were 71 episodes that met these criteria.

The team reports in the July 15 issue of Clinical Infectious Diseases that having a CD4 cell count below 200 cells/L increased the risk of serological failure (adjusted hazard ratio, 2.48). Independently of concomitant CD4 responses, receipt of HAART for more than 6 months significantly reduced this risk (adjusted hazard ratio, 0.40).

There was an 82% reduction in the risk of experiencing serologic failure in patients who had a 50% increase in CD4 cell count from baseline, compared with a 52% reduction in those receiving HAART who did not experience an immunologic response.

In addition, there was a 2% decrease in the incidence of serologic failure for every week of use of macrolides, mainly azithromycin, during follow-up.

Thus, the investigators conclude, "The use of highly active antiretroviral therapy to reverse immunosuppression and the routine use of macrolides for the prevention of opportunistic infections may reduce syphilis serologic failure rates among HIV-infected patients who have syphilis."

Clin Infect Dis 2008;47:258-265.