New research indicates that in patients co-infected with HIV, highly active antiretroviral therapy reduces syphilis serologic failure rates.
"Syphilis and [HIV] frequently coexist in patients, but the effects of immunosuppression on the course of syphilis are unknown," wrote the study's authors, Dr. Khalil G. Ghanem of Johns Hopkins University's Bayview Medical Center and colleagues.
The team studied 231 cases of syphilis in 180 HIV-positive patients, who were followed for a median of 5.3 years. There were 71 episodes of serologic failure, defined as the lack of a four-fold decrease in rapid plasma reagin titers nine to 12 months after therapy, or a four-fold increase in titers 30 days after therapy.
A CD4 cell count below 200 cells per milliliter increased the risk of serologic failure (adjusted hazard ratio, 2.48). Receipt of HAART for more than six months significantly reduced this risk (AHR, 0.40), independent of concomitant CD4 responses. Patients who had a 50 percent increase in CD4 count from baseline saw an 82 percent reduction in risk of serologic failure, compared with a 52 percent reduction for patients on HAART who did not achieve an immunologic response. During follow-up, the team noted a 2 percent decrease in serologic failure for every week of use of macrolides, chiefly azithromycin.
"Given that syphilis serological failures and neurosyphilis occur in patients with more advanced immunosuppression, immune reconstitution using [HAART] appears to be a reasonable additional intervention to try and limit poor outcomes in HIV and syphilis co-infected patients," Ghanem said.
The report, "Antiretroviral Therapy Is Associated with Reduced Serologic Failure Rates for Syphilis Among HIV-Infected Patients," was published in Clinical Infectious Diseases (2008;47:258-265).
08/19/08
UNITED STATES: HAART Improves Syphilis Serologic Response Rates in HIV Patients
Source: Reuters Health; Courtesy of the CDC National Center for HIV, STD, and TB Prevention