Allergen immunotherapy in the prevention of asthma

A survey of the prescription patterns of allergen immunotherapy in Korea

Purpose

Allergen immunotherapy (AIT) has been used as a curative and specific treatment of allergic diseases. However, no data on the prescription patterns of AIT in Korea is available. Therefore, we surveyed the prescription patterns of AIT by allergy specialists in Korea.

Methods

We emailed a questionnaire on AIT prescription patterns to the 690 members of the Korean Academy of Asthma, Allergy and Clinical Immunology with clinical practice experience. All returned answers were evaluated.

Results

The response rate was 21.0%. Only 69.0% of the respondents performed AIT in practice. Hindrance factors for performing AIT in the practice included a lack of facilities (21%), lack of practical experience during their subspecialty or postgraduate educational training programs (15.8%), no need for AIT because of sufficient pharmacotherapy (14.5%), insufficient economic profits (14.5%), and risks for adverse reactions (13.2%). Ninety-two allergy specialists (82%) performed AIT subcutaneously subcutaneous immunotherapy (SCIT) and 20 allergy specialists (18%) performed it sublingually sublingual immunotherapy (SLIT). Only 8 specialists performed both SCIT and SLIT. The allergens used for SCIT were house dust mites (98.9%), pollens (72.8%), and animal dander (23.9%). SLIT was prescribed only for house dust mites. Twenty-eight physicians (30.4%) observed anaphylactic reactions during SCIT. Eight physicians (40.0%) who prescribed SLIT observed adverse reactions, including local reactions, but none of them observed anaphylactic reactions.

Conclusions

In this survey, 69.0% of the respondents performed AIT in clinical practice. SCIT prescription is more popular than SLIT. The Lack of facilities and clinical education is a critical barrier to performing AIT. Therefore, proper clinical education of AIT is necessary for Korean allergists.

Cloning, bioinformatics analysis, and expression of the dust mite allergen Der f 5 of Dermatophagoides farinae

Crude extracts of house dust mites are used clinically for diagnosis and immunotherapy of allergic diseases, including bronchial asthma, perennial rhinitis, and atopic dermatitis. However, crude extracts are complexes with non-allergenic antigens and lack effective concentrations of important allergens, resulting in several side effects. Dermatophagoides farinae (Hughes; Acari: Pyroglyphidae) is one of the predominant sources of dust mite allergens, which has more than 30 groups of allergen. The cDNA coding for the group 5 allergen of D. farinae from China was cloned, sequenced and expressed. According to alignment using the VECTOR NTI 9.0 software, there were eight mismatched nucleotides in five cDNA clones resulting in seven incompatible amino acid residues, suggesting that the Der f 5 allergen might have sequence polymorphism. Bioinformatics analysis revealed that the matured Der f 5 allergen has a molecular mass of 13604.03 Da, a theoretical pI of 5.43 and is probably hydrophobic and cytoplasmic. Similarities in amino acid sequences between Der f 5 and allergens of other domestic mite species, viz. Der p 5, Blo t 5, Sui m 5, and Lep d 5, were 79, 48, 53, and 37%, respectively. Phylogenetic analysis indicated that Der f 5 and Der p 5 clustered together. Blo t 5 and Ale o 5 also clustered together, although Blomia tropicalis and Aleuroglyphus ovatus belong to different mite families, viz. Echimyopodidae and Acaridae, respectively.

Cloning, expression, and analysis of the group 2 allergen from Dermatophagoides farinae from China

To obtain the recombinant group 2 allergen product of Dermatophagoides farinae (Der f 2), the Der f 2 gene was synthesized by RT-PCR. The full-length cDNA comprised 441 nucleotides and was 99.3% identical to the reference sequence (GenBank AB195580). The cDNA was bound to vector pET28a to construct plasmid pET28a(+)-Der f 2, which was transformed into E. coli BL21 and induced by IPTG. SDS-PAGE showed a specific band of about 14kDa in the hole cell lysate. As estimated by chromatography, about 3.86 g of the recombinant product as obtained, which conjugated with serum IgE from asthmatic children. The protein had a signal peptide of 17 amino acids. Its secondary structure comprised an alpha helix (19.86%), an extended strand (30.82%), and a random coil (49.32%). The subcellular localization of this allergen was predicted to be at mitochondria. Furthermore, its function was shown to be associated with an MD-2-related lipid-recognition (ML) domain. The results of this study provide a solid foundation for large-scale production of the allergen for clinical diagnosis and treatment of allergic disorders.

Asthma and the unified airway

Inflammatory processes of the upper and lower airway commonly co-exist. Patients with upper respiratory illnesses such as allergic rhinitis and acute and chronic rhinosinusitis often present to both otolaryngologists and primary care physicians for treatment of their symptoms of nasal and sinus disease. These patients often have concurrent lower respiratory illnesses such as asthma that may be contributing to their overall symptoms and quality of life. Unfortunately, asthma frequently remains undiagnosed in this population. It was the objective of this paper to examine the relationship between upper respiratory illnesses such as rhinitis and rhinosinusitis and lower respiratory illnesses such as asthma, and to provide a framework for primary care and specialty physicians to approach these illnesses as a spectrum of inflammatory disease. The present manuscript was developed by a multidisciplinary workgroup sponsored by the American Academy of Otolaryngic Allergy. Health care providers in various specialties contributed to the manuscript through preparation of written materials and through participation in a panel discussion held in August 2006. Each author was tasked with reviewing a specific content area and preparing a written summary for inclusion in this final document. Respiratory inflammation commonly affects both the upper and lower respiratory tracts, often concurrently. Physicians who are treating patients with symptoms of allergic rhinitis and rhinosinusitis must be vigilant to the presence of asthma among these patients. Appropriate diagnostic methods should be used to identify individuals with concurrent respiratory illnesses, and comprehensive treatment should be instituted to reduce symptoms and improve quality of life.