Fatal food-induced anaphylaxis: Determination of tryptase and specific IgE on cadaveric blood samples. What else for a better methodological standard?

Abstract

Post-mortem investigation in cases of fatal anaphylaxis is required to provide clarifications on the presence of macroscopic pathological changes, histological features, and immunohistochemical positivity suggestive of the diagnosis, on biochemical evidence of anaphylaxis and on the presence of serological data indicative of the allergen responsible for the anaphylactic reaction. We describe the case of a 16-year-old boy with a medical history of allergic asthma, celiac disease, and known food-induced allergy for fish, fresh milk, peanuts, hazelnuts, walnuts, apples, kiwis, and peaches. Acute onset of dyspnea followed by cyanosis of the lips and respiratory failure was described immediately after having an ice cream sandwich. Unsuccessful rescues were immediately attempted with oral administration of betamethasone, intramuscular injection of adrenaline, and cardiopulmonary resuscitation. A complete post-mortem examination was performed. Serum dosage of mast cell beta-tryptase from femoral blood detecting serum values of 41.4 mg/l. Determination of specific IgE on cadaveric blood samples confirmed the anamnestic data related to sensitization for several food allergens, including cod parvalbumin, tropomyosin, brazil nut, omega-5-gliadin of foods derived from wheat and gluten. The cause of death was identified in a cardiorespiratory failure due to anaphylactic shock in a poly-allergic subject and anaphylaxis was ascribed to the wheat contained in the ice cream sandwich eaten immediately before the onset of respiratory symptoms. The need is to implement an interdisciplinary approach capable to ascertain the sensitivity and specificity of the diagnostic tests currently in use as well as to evaluate the possibility of introducing new biomarkers in practice.

Postmortem diagnostics of assumed suicidal food anaphylaxis in prison: a unique case of anaphylactic death due to peach ingestion

“…The severe and potentially lethal multi-organ hypersensitivity reaction [17] defined as anaphylactic shock is due to the exposure to a specific allergen [9,18], towards which an immune system sensitization has already developed. The reexposure to the same allergen-type I hypersensitivity IgE antibodies mediated-ultimately causes the degranulation of the mast cells and of the tissue basophils with the release of histamine and other mediators that may cause a precipitous death due to cardio-respiratory arrest [7].…”

“…However, the victim's individual baseline tryptase level cannot be evaluated ex post. Moreover, such protease level in cadaveric blood may not be relied upon the same degree of evidence and reliability as in clinical examination for multiple factors [14]: i) influence of post-mortem autolysis and PMI with antigen masking and elevation of serum proteases [2,15], ii) other morbid conditions, such as myocardial infarction [22], parasitosis with hypereosinophilia [23] and mastocytosis [9,20,24], iii) multiple trauma [25], asphyxia [26], heroin poisoning [20,27], iv) blood sampling site [20] and v) lack of standardized cut-offs [20]. Given such difficulties of interpretation, only very high post-mortem values of tryptase are accepted in the literature as significantly pivotal for a death resulting from an anaphylactic reaction [10].…”

“…In contrast, the total amount of IgE antibodies in cadaveric blood-even at average room temperature-is relatively stable after death and it can be considered as a reliable parameter associated with allergy [14]. In particular, the combination of specific IgE antibodies with tryptase levels can facilitate the differential diagnosis and significantly improve the diagnostic accuracy in post-mortem scenarios [9].…”

“…In detail, high titers of both serum tryptase and IgE antibodies were detected. As it is known, since such antibodies are relatively stable after death [9,14], they provided significant diagnostic assistance, especially after being integrated with the history and other post-mortem findings.…”

“…It is well-recognized that macroscopic autopsy findings, such as organ congestion and soft tissue edema [5], as well as conventional histology examination, are not necessarily specific for the diagnosis of lethal anaphylaxis [6,7]. For this reason, the forensic diagnosis of lethal anaphylaxis is often based on the exclusion of other possible causes, such as asphyxiation, acute drug toxicity, traumatic death, and other life-threatening diseases, in combination with a history of allergy [8,9]. Therefore, the diagnosis is generally based to some degree on circumstantial evidence that supports the existence of a causal link between the victim's death and the ingestion of certain medications or foods (dried fruit [10], shellfish [11], fresh fruit [12]), as well as animal bites or stings [2].…”