November 8, 2005
The researchers conducted a retrospective case-controlled study comparing blood plasma HIV-1 viral loads and CD4 counts in cases during early syphilis (n=63, 27 receiving antiretroviral therapy) to those before and after syphilis and with controls with non-systemic acute sexually transmitted infections (STIs) (n=104, 39 receiving ARVs). In a prospective substudy of subjects not receiving ARV therapy, semen plasma viral loads during early syphilis (n=13) were compared with subjects one month, three months and six months after syphilis treatment and with controls with no STIs (n=20).
The retrospective study found that CD4 counts were similar in cases (median 410, n=139 counts) during early syphilis compared to before (485, n=80) and after (475, n=88). A secondary analysis found a drop in CD4 count (21 percent) among those with early latent syphilis compared to controls. The investigators found that blood plasma viral loads did not change significantly overall or in subjects with primary, secondary or early latent syphilis. Effects were similar on or off ARV therapy.
The prospective study found that blood and semen viral loads were slightly higher in cases compared to controls but treatment of early syphilis did not reduce either.
"We detected no association between early syphilis and changes in blood or semen viral load or CD4 count," the authors concluded. "Increased HIV-1 infectivity associated with early syphilis is unlikely to be associated with increased levels of HIV-1 RNA in blood or semen."