Urticaria and silent parasitism by Ascaridoidea: Component-resolved diagnosis reinforces the significance of this association

Anisakis simplex and urticaria. What we know about its real incidence and management in dermatological settings?

Acute or chronic infections have been described among causes of chronic urticaria (CU). Anisakidosis is a human disease caused by the ingestion of larval nematodes of the family Anisakidae. The infestation is acquired by eating raw seafood or undercooked fish and squid. There are considerable variations in the frequency of underlying causes in the different studies and in different countries, such as differences in diets and the prevalence of infections. Anisakis simplex has been recognized as a trigger of both acute and CU manifestations. However, there is still a lack of evidence about its management and treatment in dermatology. We, therefore, reviewed some biologic properties of Anisakis simplex in order to understand the relationship between its biology and the mechanism it uses to establish chronic dermatological conditions such as urticaria and cause late complications. In addition, we herein report some concerns about the effectiveness of systemic treatment in preventing complications and management in dermatological settings.

Current insights on gut microbiome and chronic urticaria: progress in the pathogenesis and opportunities for novel therapeutic approaches

Chronic urticaria (CU) is a prevalent skin disorder greatly impacting the patients' life quality, in which immune dysregulation mediated by gut microbiome plays a significant role. Several studies have found the gut dysbiosis exists in patients with CU. In addition, infection may also be one of the causes of CU. The primary treatment currently used for CU is the second-generation non-sedating H1-antihistamines (nsAH). However, there are some limitations in current therapies. Based on the latest evidence, this review provides an updated overview of how the gut dysbiosis influences CU development, explores potential therapeutic approaches based on the gut microbiota and summarizes the interaction between gut microbiota and current treatment.

Treatment of Urticaria caused by severe cryptosporidiosis in a 17-month-old child - a case report

BACKGROUND

Cryptosporidium is an intracellular protozoan that causes gastrointestinal symptoms in humans and animals. In immunocompromised patients and children under 5 years of age, the infection is severe and can be life-threatening due to severe diarrhea.

CASE PRESENTATION

We report a case of urticaria associated with Cryptosporidium in a 17-month-old female Iranian child. The patient had moderate diarrhea (> 3 loose, watery stools but not more than 10 diarrhea stools in a day), weight loss, and acute urticarial (rash clears completely within 6 weeks). Since the child's father worked in livestock farming, the parasite may have been transferred from the cow or calve to the house and the child. Several Cryptosporidium oocysts were detected in the modified acid-fast staining of the child's stool sample. The patient was successfully treated with nitazoxanide (100 mg twice daily) and became negative for parasites three days after treatment and one week after discharge from the hospital. The child was observed to produce < 3 loose stools in the previous 24 h after 1-week post-treatment and after 6 months of follow-up.

CONCLUSION

A number of parasites are associated with urticaria, but to our knowledge, there is no information on Cryptosporidium-induced urticaria. Therefore, our result may be evidence for the role of this parasite in the development of urticaria if other causes such as food allergies, autoimmune diseases and etc. don't role in urticaria.

The Quantification of IgG Specific to α-Gal Could Be Used as a Risk Marker for Suffering Mammalian Meat Allergy

The alpha-Gal Syndrome is a delayed meat allergy characterized by the presence of sIgE against α-Gal epitope. It is known that the α-Gal present in tick saliva induces the sensitization to this epitope ending in the production of sIgG and sIgE to α-Gal. It could be considered that the more times a person is bitten by tick species, the higher the probability of making the switch from sIgG to sIgE to α-Gal and developing allergy, but it is no clear when the switch occurs. To determine the likelihood that a subject bitten by ticks but without AGS be at risk of developing this allergy, we quantified the levels of sIgG to α-Gal by an automated system (ImmunoCap). To stablish a cut-off value for sIgG to α-Gal, a receiving operating curve (ROC) was constructed. The statistical analysis demonstrated that the risk of suffering AGS in individuals bitten by ticks was 35% when the sIgG to α-Gal was greater than or equal to 40 µg/mL. Our data indicate that the sIgG values against α-Gal could be used as a prognostic marker for developing mammalian meat allergy.

Tropomyosin: A panallergen that causes a worldwide allergic problem

Background: Panallergens are proteins that take part in key processes of organisms and, therefore, are ubiquitously distributed with highly conserved sequences and structures. One class of these panallergens is composed of the tropomyosins. The highly heat-stable tropomyosins comprise the major allergens in crustaceans and mollusks, which make them important food allergens in exposed populations. Tropomyosins are responsible for a widespread immunoglobulin E cross-reactivity among allergens from different sources. Allergic tropomyosins are expressed in many species, including parasites and insects. Methods: This panallergen class is divided, according to it capacity of induced allergic symptoms, into allergenic or nonallergenic tropomyosin. Although vertebrate tropomyosins share ∼55% of sequence homology with invertebrate tropomyosins, it has been thought that the invertebrate tropomyosins would not have allergic properties. Nevertheless, in recent years, this opinion has been changed. In particular, tropomyosin has been recognized as a major allergen in many insects. Results: A high grade of homology has been shown among tropomyosins from different species, such as crustaceans and insects, which supports the hypothesis of cross-reactivity among tropomyosins from divergent species. Moreover, the emerging habit of consuming edible insects has drawn the attention of allergists to invertebrate tropomyosin protein due to its potential allergenic risk. Nevertheless, evidence about tropomyosin involvement in clinical allergic response is still scarce and deserves more investigation. Conclusion: This review intended to report allergic reactions associated with different tropomyosins when considering house dust mites, parasites, seafood, and insects, and to summarize our current knowledge about its cross-reactivity because this could help physicians to accurately diagnose patients with food allergy.

Expression and functionality of allergenic genes regulated by simulated gastric juice in Anisakis pegreffii

To better understand the molecular mechanisms underlying allergens and parasite immunity and discover the stage-enriched gene expression of fish-borne zoonotic nematodes in the stomach, we used RNA-seq to study the transcriptome profiles of Anisakis pegreffii (Nematoda: Anisakidae, AP) in simulated gastric juice. Mobile L3 larvae were incubated in simulated medium at 37 °C in 5% CO₂ (AP-GJ) and the control group larvae were collected in PBS under the same conditions (AP-PBS). We found that the sequences of A. pegreffii were highly similar to Toxocara canis sequences. Among the transcripts, there would be 138 up-regulated putative genes and 251 down-regulated putative genes in AP-GJ group. Several lipid binging-related genes were more highly expressed in AP-GJ larvae. Moreover, 17 allergen genes were up-regulated and 29 were down-regulated in AP-GJ larvae. Eleven allergen genes belonged to one or more of the following three categories: biological process, cellular component, and molecular function. According to KEGG analysis, the main pathways that were represented included protein processing in transcription, immune system, cancer, and infectious disease. In particular, the most significant changes in the expression of parasite-derived allergen products occurred in AP-GJ larvae. This study helps us to extend our understanding of the biology of the fish-borne zoonotic parasite A. pegreffii and could be helpful for more precise risk assessment and providing guidelines for allergic consumers.

Proteomic and Bioinformatic Investigations of Heat-Treated Anisakis simplex Third-Stage Larvae

Anisakis simplex third-stage larvae are the main source of hidden allergens in marine fish products. Some Anisakis allergens are thermostable and, even highly processed, could cause hypersensitivity reactions. However, Anisakis proteome has not been studied under autoclaving conditions of 121 °C for 60 min, which is an important process in the food industry. The aim of the study was the identification and characterization of allergens, potential allergens, and other proteins of heat-treated A. simplex larvae. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify 470 proteins, including allergens-Ani s 1, Ani s 2, Ani s 3, Ani s 4, Ani s 5-and 13 potential allergens that were mainly homologs of Anisakis spp., Ascaris spp., and Acari allergens. Ani s 2, Ani s 3, Ani s 5, and three possible allergens were found among the top 25 most abundant proteins. The computational analysis allowed us to detect allergen epitopes, assign protein families, and domains as well as to annotate the localization of proteins. The predicted 3D models of proteins revealed similarities between potential allergens and homologous allergens. Despite the partial degradation of heated A. simplex antigens, their immunoreactivity with anti-A. simplex IgG antibodies was confirmed using a Western blot. In conclusion, identified epitopes of allergenic peptides highlighted that the occurrence of Anisakis proteins in thermally processed fish products could be a potential allergic hazard. Further studies are necessary to confirm the IgE immunoreactivity and thermostability of identified proteins.

Analysis of Ani s 7 and Ani s 1 allergens as biomarkers of sensitization and allergy severity in human anisakiasis

The high frequency of infection by Anisakis simplex (A. simplex) has led to an increase in IgE sensitization, turning allergy to this parasite a relevant contemporary health problem. Improving the lack of conventional diagnosis test specificity is crucial to better understand these clinical scenarios. Specific IgE (sIgE) to A. simplex extract by ImmunoCAP (Anisakis-sIgE) was determined in sera from 403 blood donors (BD) from Cantabria (North of Spain) of which 51 subjects resulted sensitized. Among these latter, 47 were asymptomatic (sABD). The values of total IgE, prick-test, Anisakis-sIgE, and sIgE to Ani s 1 (anti-rAni s 1) and Ani s 7 (anti-rAni s 7) were compared between 46 sABD and 49 A. simplex allergic patients. The IgE seroprevalence by ImmunoCAP among BD was 12.65%. Allergic patients and sABD showed significant differences in all serum biomarkers evaluated. The area under the curve was assessed for Anisakis-sIgE (0.892), sIgE-rAni s 1 (0.672) and sIgE-rAni s 7 (0.668). After a severe reaction, significantly higher levels of Anisakis-sIgE and sIgE anti-rAni s 1 were detected. Determinations of sIgE by ImmunoCAP, Ani s 1 and Ani s 7 presented different sensitization patterns between allergic and asymptomatic individuals. The Ani s 1 allergen arises as a possible biomarker to detect patients at risk of suffering severe allergic reactions.