Interleukin-2 in human amniotic fluid during pregnancy and parturition: implications for prostaglandin E2 release by fetal membranes.

The potential role of interleukin 2 (IL-2) in human pregnancy was investigated by evaluating the following. (1) The presence and concentrations of IL-2 in amniotic fluid (AF) in 24 women at 16-18 weeks' gestation (Group 1) and in 27 women at term pregnancy, either before the onset of labor (Group 2, n = 10) or during spontaneous active labor (Group 3, n = 17). (2) The production of IL-2 by fetal membranes at term gestation (n = 7). (3) The release of prostaglandin E2 (PGE2) by the above tissues after stimulation with IL-2 (n = 10) or phytohemagglutinin (PHA) (n = 8). Immunoreactive IL-2 was detected only in AF samples obtained from women of Groups 1 and 3; the higher concentration was found in Group 1 samples; IL-2 was not detected in AF samples from women of Group 2. Tissues did not release IL-2. Both IL-2 and PHA exerted a significant stimulatory effect on PGE2 release by tissues. IL-2 stimulated PGE2 release by chorion tissue, but not by amnion tissue. The following conclusions can be drawn: (a) AF IL-2 might play a role in the maternal-fetal immune relationship during early pregnancy and, perhaps, during labor; (b) fetal membranes would not seem to represent a source of AF IL-2 in the absence of labor; (3) IL-2 might influence arachidonic acid metabolism through the cyclooxygenase pathway in the chorion tissue.