PROBLEM: The physiological significances of the two known subtypes of interleukin-1 (IL-1) in amniotic fluid (AF) were examined by measurements of their concentrations and detection of their location.
METHOD: Each IL-1 subtype in AF collected from 61 patients were examined by newly developed enzyme-linked immunosorbent assay with high sensitivity. Placenta and umbilical cord from 17 patients were examined immunohistochemically for localization of IL-1.
RESULTS: Different types of IL-1 were predominant in AF; the mean (± SE) concentration of IL-1β (412.8 ± 105.4pg/ml) was significantly higher (P<0.01) than that of IL-1α(116.4± 26.7 pg/ml) in cases with spontaneous vaginal delivery, whereas the concentration of IL-1α (243.1 ±81.4pg/ml) was significantly higher(P<0.01)than that of IL-1β (139.7±59.4pg/ml) in cases with premature rupture of the membranes (PROM) without intrauterine infection. In these cases, immunohistochemical studies revealed the presence of IL-1α in the trophoblastic layer of the placenta and epithelium of the umbilical cord.
CONCLUSIONS: Amniotic IL-1α was detected predominantly in cases with PROM, and it is thought to be produced in placenta and fetal skin keratinocyte.