Seroconversion of serological test for syphilis in infants born to mothers with syphilis serofast reaction

Objective To explore the influence of anti-syphilis treatment to pregnant women with lower titer seroresistance on infantile serum, so as to provide the guidance for clinical diagnosis and treatment. Methods Totally 134 cases of pregnant women with lower titer syphilis serofast reaction were divided into treatment group(75 cases) and untreated group(59 cases) according to whether received anti-syphilis treatment during their pregnancy.The change of syphilis serology toluidine red unheated serum test (TRUST) and Treponema pallidum particle assay(TPPA) for the two groups mothers and babies were compared. Results (1)The first detection of TRUST titers between the two groups of pregnant women did not show statistically significant difference (χ2=0.520, P>0.05). (2)Among the 134 neonates, 20 cases(14.9%) were negetive for both TRUST and TPPA, 23 cases(17.2%) were Treponema pallidum particle assay(TPPA) positive only, 91 cases(67.9%) were positive for both TRUST and TPPA and showed lower or equivalent TRUST titers compared to their mothers, without significant differences between the two groups(χ2=0.892, P>0.05). (3)In the two groups of babies with the same TRUST titers, the seroreversion time of TRUST showed no significant differences(P=0.229, 0.309, 1.000). The negative time of TRUST in infants with neonatal higher titer was later than those with neonatal lower titer in the two groups(all P<0.05). The infant with TRUST+ showed longer duration than those with neonatal TRUST- in TPPA seroreversion(all P<0.05). The seroreversion time of TPPA in infants with neonatal TRUST titer of 1: 4 in untreated group was later than that in treatment group[(14.1±1.4)months vs.(12.5±1.1)months, t=2.900, P=0.010]. Conclusion The treatment for mothers with lower titer seroresistance in pregnant period had no influence in the positive rate of TRUST and TPPA in the neonates and seroreversion time of TRUST in infant.It may have certain effect to shorten the seroreversion time of TPPA in infant with high TRUST titer by the treatment. Key words: Syphilis; Pregnancy; Infant; Syphilis serodiagnosis; Seroresistance