Tropomyosin in mugwort cross-reacts to house dust mite, eliciting non-Th2 response in allergic rhinitis patients sensitized to house dust mite

An overview of tropomyosin as an important seafood allergen: Structure, cross-reactivity, epitopes, allergenicity, and processing modifications

Tropomyosin (TM) is a major allergen in crustaceans, which often causes allergy and is fatal to some consumers. Currently, the most effective treatment is to avoid ingesting TM, although most adverse events occur in accidental ingestion. In this review, the molecular characterization, epitopes, cross-reactivity, and pathogenesis of TM are introduced and elucidated. Modification of TM by traditional processing methods such as heat treatment and enzymatic hydrolysis, and innovative processing technologies including high-pressure treatment, cold plasma (CP), ultrasound, pulsed electric field (PEF), pulsed ultraviolet, microwave and irradiation are discussed in detail. Particularly, enzymolysis, PEF, and CP technologies show great potential for modifying TM and more studies are needed to verify their effectiveness for the seafood industry. Possible mechanisms and the advantages/disadvantages of these technologies for the mitigation of TM allergenicity are also highlighted. Further work should be conducted to investigate the allergenicity caused by protein segments such as epitopes, examine the interaction sites between the allergen and the processing techniques and reveal the reduction mechanism of allergenicity.

Comparative analysis of chronic rhinitis patient profiles during autumn pollen season between grassland and non-grassland cities in North China

Background

The symptoms of patients with respiratory disease are influenced by local environmental factors. The incidence of allergic rhinitis in grassland areas was significantly higher than that in non-grassland areas. We aimed to compare the profiles of chronic rhinitis patients obtained during the autumn pollen season in Baotou (grassland city) and Beijing (non-grassland city), China.

Methods

Questionnaire surveys and allergen testing were conducted on 1170 and 1232 patients with chronic rhinitis visiting the Second Affiliated Hospital of Baotou Medical College and Beijing Tongren Hospital, respectively, during the autumn pollen period. Information regarding medical history, severity of symptoms, and diagnosis and treatment was collected.

Results

More patients with moderate to severe chronic rhinitis and asthma (both, P < 0.001) were present in Baotou than in Beijing. Mugwort was the most abundant allergen in both regions, but the number of patients sensitized to outdoor allergens in Baotou was higher than that in Beijing (P < 0.001). Indoor allergens in Beijing represented a considerable proportion of allergens, especially dust mites (33.4%). For patients with allergic rhinitis, nasal congestion, nasal itching, and runny nose were more severe in Baotou than in Beijing (P < 0.001). In both Baotou and Beijing, allergy (P < 0.001 vs. P = 0.004) and combined asthma (P = 0.049 vs. P = 0.005) were common factors affecting the severity of the clinical symptoms chronic rhinitis. In Baotou, age (r_s = 0.195, P < 0.001) and family allergy history (P = 0.010) were also associated with symptom severity. Although significantly more patients in Baotou received oral antihistamines, nasal corticosteroids, and surgical treatment than in Beijing (P < 0.001), the number of people receiving allergy immunotherapy in Baotou was lower (P = 0.004) and post-treatment symptom control was worse (P < 0.001) that that in Beijing.

Conclusions

During the pollen period, there were significant differences in the allergen spectrum between Baotou and Beijing. Allergy and combined asthma were common factors affecting the severity of clinical symptoms. Patients in Baotou presented with more severe clinical symptoms that were not satisfactorily managed due to the impact of pollen exposure, inconsistent access to care, and differing treatment modalities.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00591-w.

The effect of immunotherapy on cross-reactivity between house dust mite and other allergens in house dust mite -sensitized patients with allergic rhinitis

INTRODUCTION

House dust mite (HDM) is a main perennial allergen causing allergic rhinitis (AR). It has been shown that HDM cross-reacts with a variety of other allergens. Presently, allergen-specific immunotherapy (AIT) is an effective way for management of mono-sensitized HDM⁺ AR patients. However, management approaches to polysensitized HDM-sensitized AR patients are not standardized yet.

AREA COVERED

This article reviews the data available in the literature for cross-reactivity between HDM and inhalant or food allergens, the diagnosis of cross-reactivity in HDM-sensitized AR patients, and the effect of immunotherapy on cross-reactivity in HDM-sensitized AR patients; which may help to develop effective therapeutic strategies for management of polysensitized HDM-sensitized AR patients in the future.

EXPERT OPINION

Pan-allergen proteins such as tropomyosin, arginine kinase (AK), glutathione S-transferase (GST), and hemocyanin are responsible for cross-reactivity between HDM and other allergens. To distinguish genuine or cross-reactive sensitization, molecular- or component-resolved diagnosis is suggested to apply in HDM-sensitized AR patients. The effect of HDM immunotherapy to treat the associated cross-reactivity in HDM-sensitized AR patients is still contradictory, and might be dependent on the degree of homology between two allergens. Furthermore, targeting tropomyosin might be a promising way to treat HDM patients with allergen cross-reactivity.

ABBREVIATIONS

AIT: allergen-specific immunotherapy; AK: arginine kinase; AR: allergic rhinitis; CRD: component-resolved diagnostics; Der f: Dermatophagoides farina; Der p: Dermatophagoides pteronyssinus; EAACI: European Academy of Allergy and Clinical Immunology; GST: glutathione S-transferase; GWAS: genome-wide association study; HDM: house dust mite; IgE: immunoglobulin E; RAST: radioallergosorbent test; sIgE: specific IgE; SIT: specific immunotherapy; SCIT: subcutaneous immunotherapy; SLIT: sublingual immunotherapy; SPT: skin prick test.