title: Interleukin-1 receptor antagonist in the fetomaternal compartment.
abstract: Interleukin-1 (IL-1) is a major mediator in infections and inflammation. Interleukin-1 receptor antagonist (IL-1ra) opposes the actions of IL-1. IL-1ra is present in exceptionally high concentrations in third trimester amniotic fluid. We studied IL-1ra in amniotic fluid, fetal serum and newborn urine. The concentrations of IL-1ra in amniotic fluid at mid-trimester and at 25-41 gestational weeks were 6.6 +/- 0.5 ng/ml (n = 30) and 100 +/- 4 ng/ml (n = 202), respectively. At mid-trimester, amniotic fluid IL-1ra was not dependent on fetal gender, whereas during the third trimester IL-1ra was higher in female- than in male-bearing gestations. Urine of normal term newborns during the first day of life contained a very high concentration of IL-1ra (125 +/- 16 ng/ml, n = 50). Urinary concentration in female newborns was significantly higher than that in male newborns (202 +/- 19 ng/ml, n = 25 versus 49 +/- 14 ng/ml, n = 25). IL-1ra concentration in fetal serum at 22-36 gestational weeks was 0.50 +/- 0.07 ng/ml (n = 31) and at term 1.5 +/- 0.3 ng/ml (n = 17). Serum concentrations were not gender-dependent. The gender differences in IL-1ra concentrations may in part explain the lower susceptibility of female fetuses to infection.
authors.affiliation: Department of Pediatrics, University of California, Irvine 92717, USA.
authors.forename: K
authors.initials: K
authors.lastname: Bry
authors.forename: K
authors.initials: K
authors.lastname: Teramo
authors.forename: U
authors.initials: U
authors.lastname: Lappalainen
authors.forename: F
authors.initials: F
authors.lastname: Waffarn
authors.forename: M
authors.initials: M
authors.lastname: Hallman
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000652:urine*; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000037:antagonists & inhibitors*; D008297:Male; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D011994:Recombinant Proteins / Q000032:analysis*; D012737:Sex Factors; D012795:Sialoglycoproteins / Q000032:analysis* / Q000097:blood / Q000652:urine
chemical_list: C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins