Is interleukin-3 important in antiphospholipid anti body-mediated pregnancy failure?

Objective: To investigate the effect of interleuldn-3 (IL-3) on trophoblast proliferation and expression of beta (2)-glycoprotein I. Design: In vitro cell culture using primary trophoblasts and the cell lines Jeg-3, Jar, and BeWo. Setting: Department of Obstetrics and Gynaecology, University of Auckland. Patient(s): Women with normal pregnancies. Intervention(s): Increasing amounts of IL-3 were added to cultures of primary human trophoblasts, cell lines, or cells treated with a proliferation inhibiting antiphospholipid-like antibody. RNA was extracted from primary human trophoblasts or cell lines. Main Outcome Measure(s): We examined basal and IL-3-stimulated cellular proliferation by [H-3] thymidine incorporation assay and secretion of beta (2)-glycoprotein I into culture medium by semiquantative immunoblot analysis. Reverse transcriptase-polymerase chain reaction analysis was used to demonstrate the presence of IL-3 receptor transcripts. Result(s): The IL-3 treatment did not induce proliferation of highly purified primary trophoblast cultures or cell lines but did induce proliferation of contaminating CD45(+) cells in trophoblast cultures. The IL-3 did not overcome the antiproliferative effect of an antiphospholipid-like monoclonal antibody on trophoblast. Secretion of beta (2)-glycoprotein I by trophoblast cultures was time dependent but unaltered by IL-3 treatment. Conclusion(s): Our results question the proposed importance of IL-3 in antiphospholipid antibody-mediated fetal death. (Fertil Steril(R) 2001;76:700-6. (C) 2001 by American Society for Reproductive Medicine.).