Soluble HLA-G concentrations in maternal blood and cervical vaginal fluid of pregnant women with preterm premature rupture of membranes

•Serum and vaginal sHLA-G in PPROM compared to controls.•Serum and vaginal sHLA-G in PPROM in presence of histological chorioamnionitis.•Serum and vaginal sHLA-G in PPROM and their predictive role in time to delivery.

ObjectiveTo evaluate soluble HLA-G (sHLA-G) concentrations in maternal blood serum and cervical vaginal fluid in pregnancies complicated by preterm premature rupture of membranes (PPROM) compared to controls.Study designCase-control study of 24 women with PPROM and 40 controls.Main outcome measuresVaginal and serum sHLA-G and IL-6 concentrations.FindingsWomen with PPROM had significantly higher serum and vaginal sHLA-G concentrations compared to controls (respectively median 31.48 U\ml versus 13.9 U\ml p < 0.001 and 1.7 U\ml versus 0.1 U\ml p < 0.001). Vaginal expression of IL-6 was higher in PPROM cases compared to controls (respectively, median 31.19 pg\ml versus 6.67 pg\ml; p < 0.001). Higher serum and vaginal sHLA-G were associated with both a shorter length of pregnancy and histological chorioamnionitis in the PPROM group.ConclusionsHigher vaginal and serum sHLA-G in PPROM cases may be a sign of local and systemic inflammation.