BLOCKING FACTOR IN AMNIOTIC-FLUID CAUSING LEUKOCYTE MIGRATION ENHANCEMENT

Amniotic fluid (AF) caused significant leukocyte migration enhancement during the 2nd and 3rd trimester of pregnancy and in the early postpartum period when compared to the migration area obtained with an ovarian tumor homogenate antigen [Ag] (P < 0.01), choriocarcinoma spent medium (P < 0.01) and placental pool homogenate (P < 0.01). Only borderline significance (P < 0.1) was obtained when migration enhancement with AF was compared between pregnant and nonpregnant female control patients, indicating minimal unspecific activity of AF. Migration enhancement with autologous amniotic fluid was slightly larger than with homologous amniotic fluid, but the difference did not reach significance (P < 0.4). None of the control Ag caused migration enhancement; placental pool homogenate in concentrations above 4 mg percent caused migration inhibition but did not in lower concentrations. The enhancing effect of AF could be abolished by dilution but not by addition of excessive antibody to estrogen or HCG [human chorionic gonadotropin]. A blocking factor may be present in AF preventing recognition of fetoplacental Ag by the maternal immune system. In vitro leukocyte migration enhancement may correlate to in vivo graft enhancement.