USE OF LYMPHOCYTE PLATELET BINDING ASSAY FOR DETECTING A PREIMPLANTATION FACTOR - A QUANTITATIVE ASSAY

PROBLEM: To evaluate the ability of the lymphocyte/platelet binding as say to identify a preimplantation factor (PIF). METHOD: Percentages of binding of lymphocytes by platelets in the presence of sera from 30 k nown pregnant and 30 nonpregnant individuals were compared using a nov el lymphocyte/platelet binding assay. The assay is performed using a c ombination of a heat inactivated sera with donor O+ lymphocytes, activ ated complement and an antibody against CD2 (T11, Ortho Pharmaceutical s). RESULTS: In nonpregnant females (23.6 +/- 6.5%) and males (17.7 +/ - 4.7%) the percentage of lymphocytes bound by platelets was significa ntly different from pregnant women (56.1 +/- 15.9%) (P < 0.0001). Seri al sampling of blood in five women undergoing IVF/ET who had normal pr egnancies showed the detection of PIF by 4 days after transfer. The ly mphocyte/platelet binding assay was not influenced by hCG, progesteron e and estradiol. The interassay and intraassay variabilities were <3%. CONCLUSIONS: The lymphocyte/platelet binding assay is a simple, repro ducible, specific and cost efficient assay for measurement of PIE Appl ication of this assay will provide investigative and diagnostic tools for identifying and monitoring early pregnancy events.