Linkage of house dust mite allergy with the HLA region

Mice with double knockout of H2-Eb1 and H2-Ab1 exhibit reduced susceptibility to allergic rhinitis

We herein examined the importance of H2-Eb1 and H2-Ab1 in the susceptibility of mice to allergic rhinitis (AR) by developing double-gene (H2-Eb1+H2-Ab1) knockout mice. The mice were randomly grouped into different sensitization and excitation treatments, then their behavioral scores; nasal mucosa HE staining; thymus tissue toluidine blue staining; levels of ovalbumin (OVA)-specific IgE, IL-2 and IL-13 in the serum; and expression of IL-2 and IL-13 in the nasal mucosa were observed. H2-Ab1 and H2-Eb1 were both successfully knocked out in the study group (KO-OVA). Compared with the control group (WT-OVA), the nasal mucosal tissue in the KO-OVA mice showed fewer histological changes, reduced numbers of eosinophilic granulocytes, fewer mast cells in the thymus tissue, reduced concentrations of OVA-specific IgE and IL-13 in the serum, and reduced expression of IL-13 in the nasal mucosa. The behavior of the mice was also improved. In addition, the IL-2 concentration in the serum and IL-2 expression in the nasal mucosa were increased. There were two important findings of this study: (1) The H2-Ab1 and H2-Eb1 double knockout model of allergic rhinitis was successfully constructed, and the Th1/Th2 cell factors were in imbalance in these mice compared to WT mice; (2) the AR susceptibility of the dual knockout mice was reduced, confirming that H2-Ab1 and H2-Eb1 contribute to allergic rhinitis, at least in mice.

International consensus (ICON) on: clinical consequences of mite hypersensitivity, a global problem

Since mite allergens are the most relevant inducers of allergic diseases worldwide, resulting in significant morbidity and increased burden on health services, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), formed by the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), the European Academy of Allergy and Clinical Immunology (EAACI), and the World Allergy Organization (WAO), has proposed to issue an International Consensus (ICON) on the clinical consequences of mite hypersensitivity. The objectives of this document are to highlight aspects of mite biology that are clinically relevant, to update the current knowledge on mite allergens, routes of sensitization, the genetics of IgE responses to mites, the epidemiologic aspects of mite hypersensitivity, the clinical pictures induced by mites, the diagnosis, specific immunotherapeutic approaches, and prevention.

Association between HLA Class II Locus and the Susceptibility to Artemisia Pollen–Induced Allergic Rhinitis in Chinese Population

OBJECTIVE

The aim of the study was to determine whether susceptibility or resistance to Artemisia pollen-induced allergic rhinitis was associated with HLA class II DQA1, DQB1 loci. Study design and setting Forty-one subjects with allergic rhinitis and 41 healthy controls from Beijing were genotyped at HLA class II DQA1, DQB1 alleles by polymerase chain reaction amplification with sequence-specific primers-based technique.

RESULTS

The allele frequencies of HLA-DQA1*0201, DQB1*0602 were lower in patients with allergic rhinitis compared with the controls (24.39% versus 46.34%, P = 0.038; 4.88% versus 26.83%, P = 0.007), and the frequency of DQA1*0302 was higher among patients than the controls (58.54% versus 14.63%, P = 0.00004, Pc = 0.0004).

CONCLUSION AND SIGNIFICANCE

HLA-DQA1 and -DQB1 genes may be involved in the development of Artemisia pollen-induced allergic rhinitis. HLA-DQA1*0201, DQB1*0602 alleles may be a protective factor and DQA1*0302 may be a susceptible factor for Artemisia pollen-induced allergic rhinitis.

Lack of association of HLA class II alleles with peanut allergy

BACKGROUND

Peanut allergy is a common and severe phenotype of food allergy with a strong genetic component; HLA class II polymorphisms are attractive candidate genes for this disorder.

OBJECTIVE

To determine possible genotypic associations of HLA class II with peanut allergy and attempt replication of previously reported associations.

METHODS

Sibling pairs discordant for peanut allergy were genotyped (low resolution) by polymerase chain reaction-based methods to 7 DQ and 18 DR allele groups. A chi2 analysis was undertaken against sibling controls with statistical adjustment for multiple analyses.

RESULTS

Seventy-three children with confirmed peanut allergy (mean age, 6.5 years; male, 72%; asthma, 58%; atopic dermatitis, 62%; allergic rhinitis, 67%; other food allergies, 41%) and 75 of their siblings who eat peanut (mean age, 8 years; male, 52%; asthma, 12%; atopic dermatitis, 22%; allergic rhinitis, 37%; other food allergy, 7%) were genotyped. Distribution of DQ7 (29% of children with peanut allergy vs 47% sibling controls) was statistically significantly different (P = .04) before statistical correction for multiple comparisons was made by multiplying them by the number of alleles tested (and not statistically significant after correction; P = .30). Distribution of DR11 was nearly statistically significant without statistical adjustment (26% with peanut allergy vs 41% of sibling controls; P = .07; corrected P = 1.3). Alleles that were previously reported to have a weak association with peanut allergy (DRB1 *03, *08; DQB1 *0302, *04) were not verified in this cohort (unadjusted P > .44).

CONCLUSIONS

We could not establish an association between the HLA class II alleles evaluated in this cohort of sibling pairs discordant for peanut allergy.

Possible association between cockroach allergy and HLA class II antigens

BACKGROUND

Susceptibility to the development of allergic diseases is known to be associated with genetic components, as well as environmental factors. Although the genetics of immunoglobulin E, atopy, and asthma are complex, genetic markers are needed to identify populations at risk and to plan intervention studies.

OBJECTIVE

Human leukocyte antigen (HLA) class II genes play a major role in the control of immune response. We investigated the association between HLA class II alleles of DRB1 and DQB1 and the expression of atopy in cockroach-sensitive patients.

METHODS

Levels of total and specific immunoglobulin E were determined. Skin prick tests were performed. HLA class II typing was performed by the Polymerase chain reaction with sequence-specific primers. Distribution of the HLA genotypes of 32 cockroach-positive atopic patients from the inner city were compared with those of 32 healthy, nonatopic controls of Turkish Caucasian origin.

RESULTS

HLA class II gene analysis showed an increase of the HLA-DRB1*0701 and HLA-DQB1*02 alleles in atopic patients compared with nonatopic controls (31.3% vs 3.1% and 50% vs 15.6%, Pc < 0.036 and Pc < 0.021, respectively). Conversely, HLA-DRB1*15 allele was encountered more frequently in the control subjects. An association between cockroach sensitivity and cutaneous reactivity to other aeroallergens was observed (P < 0.001).

CONCLUSIONS

It is suggested that the higher frequencies of HLA-DRB1*0701 and HLA-DQB1*02 alleles are probably related to atopy rather than an association between class II antigens and cockroach allergy in this group of polysensitized, atopic individuals. Further studies may lead to a better understanding of the genetically determined susceptibility, and evaluate the individual effects of each locus (or allele) on sensitivity to specific allergens in the Turkish population.

IL4-R1 (5q31-q33) and FcepsilonRI-betaca (11q13) markers and atopy: a case/control study in a spanish population

BACKGROUND

Rhinoconjunctivitis and bronchial asthma are atopic diseases with a high prevalence in the Canary Islands (Spain). Given that the most prevalent allergen is the house-dust mite Dermatophagoides pteronyssinus, early detection of genetically susceptible subjects would allow the application of preventive measures. The objective was to investigate the possible association of IL4-R1 (chromosome 5q31-q33) and FcepsilonRI-betaca (chromosome 11q13) markers with the atopic disease in our population.

METHODS

We performed a case/control study in which patients were recruited on the basis of diagnosis of rhinoconjunctivitis and/or bronchial asthma, and positive skin prick test to D. pteronyssinus. Analysis of IL4-R1 and FcepsilonRI-betaca microsatellites was carried out by PCR and electrophoresis in acrylamide gels.

RESULTS

We have not found evidence of association between IL4-R1 and FcepsilonRI-betaca markers and atopic disease in our population. In addition, these markers have shown a high percentage of homozygosis.

CONCLUSIONS

IL4-R1 and FcepsilonRI-betaca markers have not proved to be useful genetic markers for linkage or association studies in our population.

Molecular genetics of allergic diseases

Allergic diseases affect approximately one third of the general population. This class of disease, characterized by elevated serum IgE levels and hypersensitivity to normally innocuous antigen, can manifest in practically any mucosal tissue or as a systemic response. A few examples of serious allergic diseases include asthma, dermatitis, bee sting allergy, food allergy, conjunctivitis, and severe systemic anaphylaxis. Taken together, allergic diseases constitute one of the major problems of modern day medicine. A considerable portion of the healthcare budget is expended in the treatment of allergic disease, and morbidity rates of inner city asthmatics are rising steadily. Due to the enormity of the problem, there has been a worldwide effort to identify factors that contribute to the etiology of allergic diseases. Epidemiologic studies of multigeneration families and large numbers of twins clearly indicate a strong genetic component to atopic diseases. At least two independently segregating diseasesusceptibility genes are thought to come together with environmental factors to result in allergic inflammation in a particular tissue. On the basis of the strong genetic studies, multiple groups have attempted to identify disease-susceptibility genes via either a candidate gene approach or by genome-wide scans. Both of these approaches have implicated multiple regions in the human and mouse genomes, which are currently being evaluated as harboring putative atopy genes.

Pocket 4 in the HLA-DRB1 antigen-binding groove: an association with atopy

BACKGROUND

Many studies have attempted to identify an association between HLA genes and atopy, given the role of HLA molecules in the regulation of the immune response. In the case of house-dust mites, it is difficult to find an association with a particular HLA allele, due to the complexity of the allergen. The objective was to investigate whether HLA-DRB1 functional groups are better correlated with the atopic disease in our population than DRB1 alleles.

METHODS

The method was reanalysis of the HLA-DRB1 data of a previous case/ control study.

RESULTS

The "Dr" group was found to be associated with the atopic disease in our population.

CONCLUSIONS

Grouping HLA-DRB1 alleles into functional categories may assist in the search for predictive factors in relation to atopic disease.