Potential Predictors for Serofast State after Treatment among HIV-Negative Persons with Syphilis in China: A Systematic Re¬view and Meta-Analysis

Several studies have been conducted in China in order to investigate the potential predictors of serofast state after treatment among syphilitic patients. However, there is a remarkable diversity among the results. This meta-analysis was conducted to assess potential predictors of serofast among syphilitic patients in China.

International and national electronic databases were searched up to September 2013. Reference lists of retrieved articles were also reviewed. Cohort or case-control studies addressing risk factors of serofast among syphilitic patients were included in this study.

We assessed 27 separate studies involving overall 6682 HIV-negative participants with syphilis of which 1962 remained in the serofast state. The serofast was positively associated with older age(Ptrend=0.001), female(summary risk ratio[sRR]=1.50, 95%CI:1.34-1.68), latent syphilis(sRRlatent vs primary=3.17, 95%CI: 2.66-3.77; sRRlatent vs secondary=2.00, 95%CI: 1.48-2.69) as well as non-penicillin treatment(sRR =2.99, 95%CI:2.45-3.67), but negatively associated with higher baseline titers(sRR>1:32 vs ≤1:32=0.63, 95%CI: 0.54-0.75). Compared with healthy group and serological cure group, respectively, the levels of CD4 (+), IL-2, and IL-6 among serofast patients were decreased (standardized mean difference[SMD]<0, P<0.05), but the levels of CD8(+) and IL-10 were increased(SMD>0, P<0.05). Some studies also hinted the serofast was associated with subtypes i of treponema pallidum(TP) repeat gene (RR i vs d=4.67,95%CI: 1.31-16.69) and TP occult infection.

The age, gender, stage of infection, baseline titers, treatment drug, cellular immune suppression and disorders, TP occult infection and subtypes i of TP repeat gene should be considered as important predictors of serofast. However, until now the definition and mechanism of serofast has still been not clear.