Squamous cell carcinoma antigen as a novel candidate marker for amniotic fluid embolism

AIM

We aimed to evaluate the clinical usefulness of serum squamous cell carcinoma (SCC) antigen for the diagnosis of amniotic fluid embolism (AFE).

METHODS

Sera and information of 20 patients with AFE (autopsy-proven AFE, four cases; clinical AFE, 16 cases) were obtained from the Japan Amniotic Fluid Embolism Registration Center at Hamamatsu University School of Medicine. As controls, we included 74 gestational-age-matched healthy women who gave birth to healthy newborns during the period from December 2012 to January 2014. Receiver-operator curves (ROC) were used to evaluate the diagnostic performance of SCC levels for prediction of AFE.

RESULTS

Serum SCC antigen levels in women with autopsy-proven AFE (112.0 ± 169.4 ng/mL, P = 0.001) and clinical AFE (9.5 ± 10.3 ng/mL, P = 0.004) were significantly higher than those in healthy controls with normal delivery (4.4 ± 2.2 ng/mL). On ROC analysis, the optimal cut-off value for SCC antigen levels was 7.15 ng/mL, for which the sensitivity and specificity for AFE prediction was 60.0% and 89.2%, respectively (area under the ROC, 0.785; 95% confidence interval, 0.663-0.908; P < 0.001).

CONCLUSION

Serum SCC antigen may be a promising predictor of the entry of amniotic fluid into the maternal circulation, potentially serving as a candidate marker for noninvasive diagnosis of AFE.

Amniotic Fluid Embolism: Anaphylactic Reactions With Idiosyncratic Adverse Response

PROBLEM

Amniotic fluid embolism (AFE) is a rare but severe emergency in obstetrics. The aim of the present study was to investigate the pathophysiology of AFE.

METHODS

A search was conducted between 1966 and 2014 through the English-language literature (online MEDLINE PubMed database) using the keyword amniotic fluid embolism combined with anaphylaxis, anaphylactoid, complement activation, mast cells, fetal antigens, and idiosyncratic.

RESULTS

Amniotic fluid embolism is a rare clinical entity but a severe obstetric emergency that can be lethal even in previously healthy women in labor or in the early postpartum period. There appears to be at least 2 mechanisms. First, adverse reactions in AFE are usually unexpected and fetal antigen dose dependent. Given the disastrous entry of amniotic fluid into the maternal circulation, they experience a sudden cardiopulmonary collapse (mechanical obstruction subtype). Second, anaphylactic and anaphylactoid reactions of the remaining AFE are also relatively unexpected and fetal antigen dose independent and can occur at the first exposure to amniotic fluid components. They are associated with complement activation and subsequent postpartum hemorrhage. Cardiac mast cells constitute a central pathogenesis of anaphylactic (immunoglobulin E-dependent) and anaphylactoid (immunoglobulin E-independent) reactions.

CONCLUSIONS

Recent immunologic studies provide a new approach to the study of the pathophysiology of AFE.

Evaluation of vaginal fluid squamous cell carcinoma antigen test in diagnosis of premature rupture of membranes

OBJECTIVE

Previous studies have reported that concentrations of squamous cell carcinoma (SCC) antigen in amniotic fluid are extremely higher than that in the maternal serum. The aim of this study was to assess the potential clinical utility of vaginal fluid SCC level as a marker for diagnosing premature rupture of membranes (PROM).

METHODS

A case-control study was performed using patients admitted to Nara Medical University Hospital, delivery ward, from January 2011 to December 2012. The discriminatory potential of SCC assay was determined using 54 PROM and 108 gestational age-matched control vaginal fluid samples, in a 1:2 ratio. Levels of vaginal fluid SCC in patients with PROM and control pregnant women were quantified by an enzyme-linked immunosorbent assay.

RESULTS

The statistical results showed no correlation between gestational age and vaginal fluid SCC levels. There was no significant difference in vaginal fluid SCC levels between patients with PROM and those with control pregnant women (16156.5 ± 10495.8 ng/mL versus 15471.9 ± 11362.2 ng/mL, p = 0.467).

CONCLUSION

We conclude that SCC could not be regarded as a potential marker for diagnosis of PROM. SCC may be a physiologic constituent of the vaginal fluid during pregnancy.

Incidence, diagnosis and pathophysiology of amniotic fluid embolism

Amniotic fluid embolism (AFE) is a rare clinical entity, sometimes fatal. A review was conducted to describe the frequency, diagnosis and pathophysiology of AFE. The reported incidences ranged from 1.9 cases per 100,000 maternities (UK) to 6.1 per 100,000 maternities (Australia), which can vary considerably, depending on the period, region of study and the definition. Although the development of amniotic fluid-specific markers would have an impact on early diagnosis, definition of AFE based on these markers is not widely accepted. To date, immunological mechanisms, amniotic fluid-dependent anaphylactic reaction and complement activation, have been proposed as potential pathogenetic and pathophysiological mechanisms. Immune cell activation induced through complement activation may be associated with the mechanism that immediately initiates maternal death, only in susceptible individuals. This review will focus on advances in the field of AFE biology and discuss the prevalence, diagnosis and pathophysiology of AFE.