Evaluation of specific marker CK13 and CK10/13 combined with APM staining for the diagnosis of amniotic fluid embolism and aspiration

• CK13, CK10/13 with APM stain specifically identified amniotic fluid squamous cells.
• CK13 and CK10/13 are reliable biomarkers of amniotic fluid squamous cells.
• These stains improve accuracy in diagnosis of amniotic fluid embolism/aspiration.

ObjectiveTo explore the value of CK13 (Rab) and CK10/13(Mab) as objective and specific biomarkers combined with Alcian-Phloxine-Martius yellow (APM) staining for the diagnosis of amniotic fluid embolism (AFE) and amniotic fluid aspiration (AFA).MethodsA retrospective study of forensic autopsy cases of 148 neonatal deaths and 19 maternal deaths in the perinatal stage was conducted at the Institute of Pathology and Forensic Medicine, Zhejiang University. Medical records were reviewed and monoclonal antibody for CK13 (Rab) and CK10/13 (Mab) as immunostaining of amniotic fluid squamous cells, APM staining, and Hematoxylin and Eosin (HE) staining were used to diagnose the AFE and AFA. Descriptive statistics of the patient population were analyzed using SPSS 20.0 software.ResultsImmunoreactivity of CK13 and CK10/13 specifically identified squamous cells of all the AFE and AFA cases. The amniotic fluid squamous cells were stained positive in a deep brown color with the monoclonal antibody to CK 13 and CK10/13 whereas the endothelial cells and alveolar epithelial cells were negative. There was no CK13 or CK10/13 expression in the non-AFE and non-AFA cases. With APM staining keratinized squamous cells were pink and mucus was blue-green in marked contrast with the surrounding tissue, which improved the detection rates of both keratinized squamous cells and mucus.ConclusionsCK13 (Rab) and CK10/13 (Mab) are valuable and reliable biomarkers of amniotic fluid squamous cells. APM reveals enriched mucus and keratinized squamous cells of amniotic fluid. Immunohistochemical detection of CK13 and CK10/13 combined with APM staining can improve the accuracy and reduce the difficulty in the diagnosis of AFE and AFA.