[A new histologic diagnosis for amniotic fluid embolism by monoclonal antibody TKH-2 that recognizes mucin-type glycoprotein].

Sialyl Tn structure (NeuAc alpha 2-6 GalNAc 1-0-Ser/Thr) recognized by monoclonal antibody TKH-2 is a characteristic component in meconium- and/or amniotic fluid-derived mucin. The purpose of this study was to evaluate whether immunohistochemical staining employing antibody TKH-2 is a sensitive method for histological diagnosis of amniotic fluid embolism (AFE). The intravenous injection of 10% meconium solution (1 ml/kg) into rabbits was carried out. Formalin-fixed, paraffin-embedded lung, liver, and kidney tissue sections were obtained at various time interval after injections. Specimens were stained by the Streptavidin Biotin Complex method. The results of immunostaining were compared to those of hematoxylin and eosin (H & E) stain or a conventional Alcian blue stain. Remarkable positive stainings were easily seen within the pulmonary artery vasculature in experimental rabbits. Meconium-derived mucin can be easily missed on H & E sections. Compared to TKH-2 staining, Alcian blue staining may also be insufficient to demonstrate intravascular mucin in the lung sections. TKH-2 staining is the most sensitive method to use in detecting meconium-derived mucin in the lung sections of rabbits with an AFE experimental model.