A simple, noninvasive, sensitive method for diagnosis of amniotic fluid embolism by monoclonal antibody TKH-2 that recognizes NeuAc alpha 2-6GalNAc.

OBJECTIVE: The sialyl Tn structure (NeuAc alpha 2-6GalNAc alpha 1-O-Ser/Thr) recognized by monoclonal antibody TKH-2 is a characteristic component in meconium and amniotic fluid. The purpose of this study was to determine whether amniotic fluid embolism could be detected by quantification of this antigen in maternal serum by means of an assay using antimucin monoclonal antibody TKH-2.

STUDY DESIGN: Sialyl Tn antigen was measured in the serum of women with meconium-stained amniotic fluid and compared with the level in those with clear amniotic fluid, as well as that in women with a clinical picture suggesting amniotic fluid embolism. The concentration of sialyl Tn antigen was determined by an immunoradiometric competitive inhibition assay.

RESULTS: Serum sialyl Tn antigen levels in women with meconium-stained amniotic fluid (20.3 +/- 15.4 U/ml) at delivery were slightly higher than those in women with clear amniotic fluid (11.8 +/- 5.6 U/ml). A significantly elevated level of sialyl Tn antigen was observed in serum of patients with amniotic fluid embolism and amniotic fluid embolism-like symptoms (105.6 +/- 59.0 U/ml, p < 0.01).

CONCLUSION: The method for detecting sialyl Tn antigen in the serum of patients with amniotic fluid embolism is a direct way to demonstrate the release of meconium- or amniotic fluid-derived mucin into the maternal circulation and is a simple, noninvasive, sensitive method for diagnosis of amniotic fluid embolism.