Conclusions
(1) We report for the first time the presence of CXCL13 in AF. (2) AF CXCL13 concentrations are dramatically increased in IAI. (3) Unlike other chemokines, AF and serum CXCL13 concentrations did not change with spontaneous parturition.
Results
(1) CXCL13 was present in 100% of serum and cord blood samples, and 99% of AF samples (339/343). (2) Serum CXCL13 concentration was significantly higher in pregnant women when compared to non-pregnant women (median 313.3 pg/mL (interquartile range (IQR) 197.2-646.9) vs. 40.5 pg/mL (IQR 29.5-93.5), respectively; p < 0.001). (3) Serum CXCL13 concentration decreased with advancing gestational age (Spearman's Rho = -0.424; p < 0.001). (4) There were no significant differences in the median serum CXCL13 concentration between women at term with and without labor (371.6 pg/mL (IQR 194.3-614.3) vs. 235.1 pg/mL (IQR 182.8-354.7), respectively; p = 0.6). (5) The concentration of CXCL13 in AF did not change with gestational age (p = 0.1). (6) Patients with PTL and delivery with IAI had a significantly higher median concentration of CXCL13 than those without IAI (median 513.2 pg/mL (IQR 199.7-2505.5) vs. 137.3 pg/mL (IQR 96.7-209.6), respectively; p < 0.001) and those who delivered at term (133.7 pg/mL (IQR 97.8-174.8); p < 0.001). (7) Spontaneous labor did not result in a change in the median AF concentration of CXCL13 (labor: 86.9 pg/mL (IQR 55.6-152.0) vs. no labor: 77.8 pg/mL (IQR 68.0-98.0); p = 0.8). (8) CXCL13 was immunolocalized to macrophages in fetal membranes and umbilical vein. Conclusions: (1) We report for the first time the presence of CXCL13 in AF. (2) AF CXCL13 concentrations are dramatically increased in IAI. (3) Unlike other chemokines, AF and serum CXCL13 concentrations did not change with spontaneous parturition.