Amniotic fluid soluble human leukocyte antigen-G in term and preterm parturition, and intra-amniotic infection/inflammation

Abstract

Objective Circulating soluble HLA-G (sHLA-G) has been associated with pregnancy complications, and determination of sHLA-G concentrations in amniotic fluid (AF) has been reported in normal pregnancies. Our aim was to determine if the AF concentrations of sHLA-G change with advancing gestation, spontaneous labor at term, and in patients with spontaneous preterm labor (PTL) with intact membranes, as well as in those with preterm prelabor rupture of membranes (PROM), in the presence or absence of intraamniotic infection/inflammation (IAI). Study design This cross-sectional study included the following groups: 1) midtrimester (n=55); 2) normal pregnancy at term with (n=50) and without (n=50) labor; 3) spontaneous PTL with intact membranes divided into: a) PTL who delivered at term (n=153); b) PTL who delivered preterm without IAI (n=108); and c) PTL with IAI (n=84); and 4) preterm PROM with (n=46) and without (n=44) IAI. sHLA-G concentrations were determined by ELISA. Non-parametric statistics were used for analysis. Results 1) Among patients with PTL, the median AF sHLA-G concentration was higher in patients with IAI than in those without IAI or women that delivered at term (p<0.001 for both comparisons); 2) Similarly, patients with preterm PROM and IAI had higher median AF sHLA-G concentrations than those without IAI (p=0.004); 3) Among patients with PTL and delivery, those with histologic chorioamnionitis and/or funisitis had a higher median AF sHLA-G concentration than those without histologic inflammation (p<0.001); and 4) The median AF sHLA-G concentration did not change with advancing gestational age. Conclusions AF sHLA-G concentrations are elevated in preterm parturition associated to IAI as well as in histologic chorioamnionitis. We propose that sHLA-G may participate in the regulation of the host immune response against intra-amniotic infection.

Increased human leukocyte antigen-G expression at the maternal–fetal interface is associated with preterm birth

“…In a subgroup analysis of our data, spontaneous PTB was associated with increased basal plate HLA-G, whereas indicated PTB was not. Our data are consistent with the findings of Kusanovic et al, who demonstrated that levels of soluble HLA-G in the amniotic fluid were elevated in patients with spontaneous preterm labor[32]. …”

Clinical significance of oligohydramnios in patients with preterm labor and intact membranes*,**

“…Thus, this information can be used for counseling patients about their risk for delivery and the need to assess the AF for inflammation. Previous studies have reported that intra-amniotic inflammation is associated with preterm labor[4-7, 12-13, 15, 18-19, 21-24, 27-29, 31-34, 38, 41-43, 47-49] and is a risk factor for adverse outcome [2, 14, 16, 26, 39, 45, 52-53, 56-57]. …”

Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery

“…The mechanism of disease responsible for chronic chorioamnionitis is thought to be maternal antifetal rejection. There is also evidence for antibody-mediated fetal rejection; maternal antibodies against paternal human leukocyte antigens (HLA) have been demonstrated in patients with chronic chorioamnionitis [93, 99, 100, 127]. The control group consisted of uncomplicated term deliveries.…”