Lack of evidence of a significant association between HLA-DR, DQ and DP genotypes and atopy in families with HDM allergy

Introduction of complementary foods in infancy and atopic sensitization at the age of 5 years: timing and food diversity in a Finnish birth cohort

OBJECTIVE

To study the associations between timing and diversity of introduction of complementary foods during infancy and atopic sensitization in 5-year-old children.

METHODS

In the Finnish DIPP (type 1 diabetes prediction and prevention) birth cohort (n = 3781), data on the timing of infant feeding were collected up to the age of 2 years and serum IgE antibodies toward four food and four inhalant allergens measured at the age of 5 years. Logistic regression was used for the analyses.

RESULTS

Median duration of exclusive and total breastfeeding was 1.4 (interquartile range: 0.2-3.5) and 7.0 (4.0-11.0) months, respectively. When all the foods were studied together and adjusted for confounders, short duration of breastfeeding decreased the risk of sensitization to birch allergen; introduction of oats <5.1 months and barley <5.5 months decreased the risk of sensitization to wheat and egg allergens, and oats additionally associated with milk, timothy grass, and birch allergens. Introduction of rye <7.0 months decreased the risk of sensitization to birch allergen. Introduction of fish <6 months and egg ≤11 months decreased the risk of sensitization to all the specific allergens studied. The introduction of <3 food items at 3 months was associated with sensitization to wheat, timothy grass, and birch allergens; the introduction of 1-2 food items at 4 months and ≤4 food items at 6 months was associated with all endpoints, but house dust mite. These results were particularly evident among high-risk children when the results were stratified by atopic history, indicating the potential for reverse causality.

CONCLUSIONS

The introduction of complementary foods was consecutively done, and with respect to the timing of each food, early introduction of complementary foods may protect against atopic sensitization in childhood, particularly among high-risk children. Less food diversity as already at 3 months of age may increase the risk of atopic sensitization.

HLA-DR polymorphism modulates response to house dust mites in a transgenic mouse model of airway inflammation

We and others have reported that HLA-DRB1*03 is associated with childhood asthma. To extend this observation and to prove this association, we sensitized and challenged either HLA-DR2 (HLA-DRB1*1502) or HLA-DR3 (HLA-DRB1*0301) transgenic mice with house-dust mite extract. Inflammatory cell counts and cytokine levels in the bronchoalveolar lavage (BAL) fluid between HLA-DR3 and DR2 mice were compared. HLA-DR3 transgenic mice had significantly elevated eosinophil counts, Interleukin-4 and Interleukin-13 levels in the BAL fluid but not interferron gamma-γ. Thus, our study suggests that HLA-DRB1*0301 plays an important role in mounting a Th2-predominant immune response to house dust mite and Th2-type inflammation in the lung.

Characterization of HLA class II/peptide-TCR interactions of the immunodominant T cell epitope in Art v 1, the major mugwort pollen allergen

More than 95% of mugwort pollen-allergic individuals are sensitized to Art v 1, the major allergen in mugwort pollen. Interestingly, the CD4 T cell response to Art v 1 involves only one single immunodominant peptide, Art v 1(25-36) (KCIEWEKAQHGA), and is highly associated with the expression of HLA-DR1. Therefore, we investigated the molecular basis of this unusual immunodominance among allergens. Using artificial APC expressing exclusively HLA-DRB1*0101 and HLA-DRA*0101, we formally showed that DR1 acts as restriction element for Art v 1(25-36)-specific T cell responses. Further assessment of binding of Art v 1(25-36) to artificial HLA-DR molecules revealed that its affinity was high for HLA-DR1. Amino acid I27 was identified as anchor residue interacting with DR molecules in pocket P1. Additionally, Art v 1(25-36) bound with high affinity to HLA-DRB1*0301 and *0401, moderately to HLA-DRB1*1301 and HLA-DRB5*0101, and weakly to HLA-DRB1*1101 and *1501. T cell activation was also inducible by Art v 1(25-36)-loaded, APC-expressing HLA molecules other than DR1, indicating degeneracy of peptide binding and promiscuity of TCR recognition. Specific binding of HLA-DRB1*0101 tetramers containing Art v 1(19-36) allowed the identification of Art v 1(25-36)-specific T cells by flow cytometry. In summary, the immunodominance of Art v 1(25-36) relies on its affinity to DR1, but is not dictated by it. Future investigations at the molecular HLA/peptide/TCR and cellular level using mugwort pollen allergy as a disease model may allow new insights into tolerance and pathomechanisms operative in type I allergy, which may instigate new, T cell-directed strategies in specific immunotherapy.

Is allergenic similarity predictable in respiratory allergies?

BACKGROUND

First degree relatives of patients with allergic diseases are at increased risk of having the disorder. However, it is not clear whether two such related patients with allergic diseases are sensitive to the same antigens or not.

OBJECTIVE

The aim of this study to determine whether or not first degree relatives with respiratory allergies are more likely to be skin test positive to the same allergen extracts as unrelated patients.

PATIENTS AND METHODS

Skin test results for 35 common aeroallergens were compared in 264 pairs of genetically related subjects and 264 pairs of age and sex matched, but unrelated, subjects. We calculate the percentages of the concordant and discordant results in each group. Results are compared by using chi2 test.

RESULTS

For all related and unrelated groups combined, there were significant differences with mites (der. pteronyssinus, der. farinae) and some moulds (aspergillus mix and rhizopus nigricans) (p<0.05); When the groups were subdivided into parent-child pairs and same or different sibling pairs, and the same comparisons were made, a significant difference was only found in both sibling pairs (p<0.05), not in parent-child pairs (p>0.05). Since there was no both positivity with aspergillus mix and rhizopus nigricans in the two groups, these two allergens were excluded from the study.

CONCLUSION

It is concluded that we could not say that if one or both of parents are atopic to any allergens, their child will be atopic to the same allergens. Besides, when a respiratory allergy occurs in siblings, only the one who has house dust mite allergy sensitivity can possess the similar antigen sensitivity.

HLA antigens in Greek children with allergic bronchial asthma

The aim of our study was to investigate the genetic linkage between mite allergic bronchial asthma and HLA class I and II antigens and haplotypes. Sixty Greek children with allergic bronchial asthma due to mite sensitivity (Dermatophagoides pteronyssinus and Dermatophagoides farinae) and their family members were typed for HLA class I and II antigens (total 263 subjects). One hundred and twenty-five healthy, unrelated Greek children without medical history of atopy were also typed as control group. Major histocompatibility complex class I and II gene analysis revealed that only HLA-DRB1*04 and HLA-DQA1*0301 alleles are possibly important factors in the development of atopic asthma in Greek children with sensitivity to mites. No significant differences among the HLA-DRB1*04 subtypes have been established. Transmission disequilibrium test revealed that no specific HLA-A, -B, -DRB1, -DQA1 and -DQB1 alleles were transmitted preferentially to the affected children. HLA-DQB1*0301-4 alleles were associated with high levels of total serum immunoglobulin E in affected children. The study of the HLA haplotypes failed to demonstrate any significant association between any extended or natural selection haplotype and mite allergic bronchial asthma in Greek children.

Association studies for asthma and atopic diseases: a comprehensive review of the literature

Hundreds of genetic association studies on asthma-related phenotypes have been conducted in different populations. To date, variants in 64 genes have been reported to be associated with asthma or related traits in at least one study. Of these, 33 associations were replicated in a second study, 9 associations were not replicated either in a second study or a second sample in the same study, and 22 associations were reported in just a single published study. These results suggest the potential for a great amount of heterogeneity underlying asthma. However, many of these studies are methodologically limited and their interpretation hampered by small sample sizes.

HLA class II genotypic frequencies in atopic asthma: association of DRB1*01-DQB1*0501 genotype with Artemisia vulgaris allergic asthma

Different human leukocyte antigen (HLA) class II alleles have been associated with the development of atopic asthma. To determine whether HLA class II alleles are associated with atopic asthma in a population from southeast Spain (Murcia region), 213 atopic asthmatic patients and 150 controls were selected for HLA typing. Significant association of the DRB1*01 and DQB1*0501 alleles was found in Artemisia vulgaris allergic patients (p(c) = 0.00052 and p(c) = 0.00023, respectively). No significant correlation was found in other atopic patients allergic to pollens (Phleum pratense, Olea europaea, and Salsola kali), house dust mites (Dermatophagoides pteronyssinus, D. farinae), molds (Alternaria alternata, Cladosporium herbarum), or animal danders (dog, cat). The results reveal that the DRB1*01-DQB1*0501 genotype is strongly associated with a positive response to Artemisia vulgaris in the population studied.

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.

Positive association between HLA-DRB1*07 and specific IgE responses to purified major allergens of D. pteronyssinus (Der p 1 and Der p 2)

BACKGROUND AND OBJECTIVE

Human leukocyte antigen (HLA) class II gene products are involved in the antigen presentation of exogenous antigens. The aim of this study was to evaluate whether specific immunoglobulin (Ig)E responses to purified major allergens of Dermatophagoides pteronyssinus (Der p 1 and Der p 2) were associated with genotypes of HLA-DRB1 alleles.

SUBJECTS AND METHODS

Peripheral venous blood samples were collected from two groups of unrelated Korean adolescents: 168 subjects with positive skin response (wheal > or = 3 mm) to crude D. pteronyssinus allergens and 94 age-matched controls with negative skin response and low serum-specific IgE to crude D. pteronyssinus allergens. The former group was found to contain 104 with high serum-specific IgE to crude D. pteronyssinus allergens, 100 with high serum-specific IgE to Der p 1, and 122 with high serum-specific IgE to Der p 2. Genotypes of the HLA-DRB1 alleles were determined using polymerase chain reaction-sequence specific oligonucleotide probes.

RESULTS

HLA-DRB1*07 was significantly higher in subjects with a high serum-specific IgE response to crude D. pteronyssinus allergens than the controls (16.3% vs 3.2%, odds ratio [OR] = 5.93, corrected P [Pc] = 0.02). The excess of DRB1*07 was more marked in those with high serum-specific IgE responses to Der p 1 or Der p 2 than the controls (20.0% vs 3.2%, OR = 7.58, Pc = 0.004; 18.9% vs 3.2%, OR = 7.05, Pc = 0.006). Among subjects with high serum IgE to Der p 1, DRB1*13 significantly increased than the controls (32.0% vs 13.8%, OR = 2.93, Pc = 0.03).

CONCLUSIONS

We clearly observed the association between HLA-DRB1 alleles and specific IgE responsiveness to D. pteronyssinus major allergens. The molecular mechanism of HLA-DRB1*07 and DRB1*13 involvement in D. pteronyssinus-specific IgE responsiveness awaits further investigation.

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.

HLA DPB1*0201 allele is negatively associated with immunoglobulin E responsiveness specific for house dust mite allergens in Taiwan

BACKGROUND

House dust mite (HDM) Dermatophagoides pteronyssinus is the most important source of indoor allergens that cause allergic diseases in Taiwan. We prepared purified HDM allergens (Der p 1, Der p 2 and Der p 5) to detect allergen-specific immunoglobulin (Ig) E responsiveness among a large number of test subjects. The robust genetic typing system for HLA class II genes also facilitated the study on association of HLA and allergic response toward HDM.

OBJECTIVE

This study intended to investigate the association between HLA class II alleles and the IgE responsiveness to the major allergens from HDM, D. pteronyssinus.

METHODS

Two hundred and forty-eight subjects were selected for HLA association study. Plasma HDM allergen (Der p 1, Der p 2, Der p 5) -specific IgE and Der p 2-specific IgG antibodies were detected by ELISA, while HLA class II -DRB1, -DQA1, -DQB1, -DPB1 genetic polymorphism was determined by polymerase chain reaction/sequence-specific oligonucleotide probe hybridization (PCR/SSOPH). Statistical comparison of the allelic distribution of each HLA class II genes among the individuals with/without HDM allergen-specific IgE and IgG antibodies were performed.

RESULTS

There was no significant association between HLA DRB1, DQB1, DQA1 alleles and HDM-specific IgE responsiveness noted. Only DRB1*0803 and the linked DQA1*0103 alleles showed positive association with Der p 5-specific IgE responsiveness. However, we found that HLA-DPB1*1301 predisposed subjects to IgE responsiveness to HDM Der p 5. HLA DPB1*0501 was weakly associated with the IgE responsiveness to HDM Der p 1 and Der p 5. There was a strong negative association between the HLA-DPB1*0201 allele with IgE responsiveness to Der p 1 (OR: 0.30, P </= 0.0001, P </= 0.0007, Pc </= 0.010).

CONCLUSION

We clearly observed the association between HLA DPB1 alleles and specific IgE responsiveness to HDM major allergens. The molecular mechanism of HLA-DPB1*0201 involvement in protecting subjects from HDM-specific IgE responsiveness awaits further investigation.

Genetic linkage of HLA-class II locus to mite-specific IgE immune responsiveness

BACKGROUND

IgE response to common inhalant allergens seems to be the major determinant of the development of atopic rhinitis and asthma but it has been difficult to demonstrate genetic control of the IgE response.

OBJECTIVE

To investigate genetic linkage between specific IgE reactions to purified aero-allergens (grass, birch, cat, mite) and the HLA-class II locus.

METHODS

DNA-based HLA-class II typing was performed for determination of DRB1, DQB1 and DPB1 alleles. Linkage was studied by the affected sibpair method and the extended transmission disequilibrium test in 100 children from 40 nuclear families selected from a homogeneous population in south-western Germany.

RESULTS

Significant linkage of mite-specific IgE response to HLA-DPB (P = 0.00001), HLA-DRB (0.02) and HLA-DQB (P = 0.001) was revealed by sibpair analysis of MHC class II alleles and confirmed by the extended transmission disequilibrium test for HLA-DRB (P = 0.01) and HLA-DPB (P = 0.04). No consistent significant linkage between the HLA-class II locus and IgE response to grass pollen, birch pollen, and cat dander could be demonstrated.

CONCLUSION

The findings are consistent with the existence of one or more genes in the HLA-class II region modifying the IgE immune response to common environmental allergens.

Linkage of house dust mite allergy with the HLA region

BACKGROUND

Atopy is a multifactorial disease, the pathogenesis of which is influenced by both genetic and environmental conditions. Genes in the HLA region have been involved in the control of the IgE response.

OBJECTIVE

In order to investigate whether allergy to house dust mite is associated with HLA in our population, we performed sib-pair analysis in 18 families and a case/control study of 161 non-related individuals.

METHODS

Levels of total and specific IgE were determined, skin-prick tests were carried out and clinical history was reviewed for every subject in the study. HLA class II typing was performed by the polymerase chain reaction with sequence specific primers.

RESULTS

We observed a significant difference from expected values in haplotypes shared by affected sibs; however, the case/control study did not reveal any association with any particular allele.

CONCLUSION

These results suggest that any particular HLA-DRB1/DQA1/DQB1 allele is responsible for the development of allergy to house dust mite in the Spanish population. Some other locus in or close to the HLA region might be involved, e.g., the tumour necrosis factor gene, a possibility that would explain the significant difference from expected values in the segregation of HLA haplotypes.

Immunogenetics of atopic asthma: association of DRB1*1101 DQA1*0501 DQB1*0301 haplotype with Dermatophagoides spp.-sensitive asthma in a sample of the Venezuelan population

BACKGROUND

Genes linked to the major histocompatibility complex (MHC), have been implicated in atopic asthma. Asthma is highly prevalent in the Venezuelan population (estimated at 20%) and genetic markers are needed to identify populations at risk and plan intervention strategies.

OBJECTIVE

To study the influence of the MHC class I and class II genes in the susceptibility to atopic asthma.

METHODS

MHC-class I HLA-A, -C, -B and MHC-class II HLA-DR, -DQ, -DP gene haplotype frequencies were determined in 135 Venezuelan mestizos, 71 belong to 20 atopic asthmatic families and 64 unrelated controls. The index cases were 20 atopic asthmatics with positive skin-prick tests and specific serum immunoglobulin E (IgE) for Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f). To ascertain the genes associated with susceptibility to atopy and/or asthma, two control groups were studied, 41 non-atopic subjects with skin-prick negative test, and undetectable levels of specific IgE and 23 non-asthmatic atopic subjects with detectable specific IgE to Der p and Der f. A linkage analysis was performed in those families with two or more atopic siblings (with or without asthma).

RESULTS

MHC-class I genes analysis showed that HLA-Cw7 was absent in the asthmatic patients studied, whereas the frequency of this allele was 14.3% in non-atopic controls (P = 0.0 17, PC = 0.19) and 20.8% in the atopic controls (P = 0.0066, PC = 0.07). MHC-class II gene analysis showed a significant increase of the HLA-DRB1*11 in the asthmatic patients compared with non-atopic controls (allele frequencies of 25.6 vs 4.4% P = 0.0017, PC = 0.02). There were no significant differences among asthmatic and atopic controls in the frequency of HLA-DRB1*11 (25.6 vs 17.4%). In contrast, the HLA-DRB1*1101+ haplotypes were significantly higher in asthmatics compared with atopic and non-atopic controls (19.6% vs 2.2% vs 2.3%, PC<0.05). The HLA-DRB1*1101, DQA1*0501, DQB1*0301 haplotype was found significantly increased in the patients vs non-atopic controls (15.4 vs 1.1%, PC< 0.01). The serum levels of specific IgE were detectable in both atopic asthmatics and atopic controls; however, it was higher in atopic asthmatics vs atopic controls Der p (median, 58.7 vs 2.7 kU/L, P<0.001) and Der f (median, 46.9 vs 2.7 kU/L, P<0.001). No linkage between MHC genes and mite-atopy could be documented on informative families with two or more atopic siblings.

CONCLUSIONS

We have identified an association between the haplotype HLA-DRB1*1101, DQA1*0501, DQB1*0301 and atopic asthma that confers susceptibility to develop mite-sensitive asthma to atopics (relative risk, RR 8.2), and to non-atopic controls (RR = 15.8) that carry this haplotype. Conversely, the allele HLA-Cw7 was absent in the asthmatics studied and had higher frequencies in the atopic (RR = 0.05) and non-atopic (RR = 0.08) controls. Thus, it may have a protective role for developing atopic asthma in the population studied.

Linkage analysis of Dermatophagoides pteronyssinus-specific IgE responsiveness with polymorphic markers on chromosome 6p21 (HLA-D region) in Caucasian families by the transmission/disequilibrium test. Collaborative Study on the Genetics of Asthma (CSGA)

BACKGROUND

Recently, we have obtained evidence for linkage between Der p 1-specific IgE antibodies and markers on chromosome 6p21 (HLA-D region) in a genome-wide screening in Caucasian families recruited as a part of the Collaborative Study on the Genetics of Asthma (CSGA).

OBJECTIVE

Specific IgE antibodies toward different Dermatophagoides pteronyssinus (Der p) polypeptides were detected by immunoblotting analysis, and the transmission/disequilibrium test (TDT) was performed between specific IgE responsiveness toward each different Der p polypeptide and markers on chromosome 6p21 to better clarify the genetic contribution of HLA-D genes.

METHODS

We studied 299 individuals in 45 Caucasian families participating in the CSGA. Serum samples from 137 individuals that showed elevated specific IgE antibodies toward the Der p crude allergen (> -0.5 log IU/mL) by ACCESS immunoassay were subjected to immunoblotting analysis. TDT was conducted between the presence of specific IgE antibodies toward each of 12 different Der p polypeptides and 4 polymorphic markers on chromosome 6p21.

RESULTS

The 196-bp allele of D6S1281 and the 104-bp allele of DQCAR showed significant excess transmission to specific IgE responders toward a particular Der p polypeptide (120 kd, 55 kd, 45 kd, or 37 kd). In contrast, the 200-bp allele of D6S1281 and the 204-bp allele of D6S291 showed significantly decreased transmission to specific IgE responders toward a particular Der p polypeptide (120 kd, 90 kd, 52 kd, or 45 kd). Deviation from the expected 50% transmission in heterozygous parents was statistically significant after correcting for multiple comparisons.

CONCLUSION

This study supported our previous findings that genes on chromosome 6p21 (HLA-D region) may influence the expression of Der p-specific IgE responsiveness in this Caucasian population. Our results, however, reveal the complexity of genetic regulations of Der p-specific IgE responsiveness by HLA-D genes, suggesting the strong influence of non-HLA loci and perhaps environmental factors for the development of Der p-specific IgE responsiveness.

HLA class II DRB1, DQB1 and DPB1 genotypic associations with peanut allergy: evidence from a family-based and case-control study

BACKGROUND

Peanut is one of the most common foods provoking allergic reactions and is the most frequent cause of fatal and near-fatal food-induced anaphylaxis. However, as yet, little is known of the genetic and immunological mechanisms which underly peanut allergy.

OBJECTIVE

Based on findings in other allergic diseases, we have investigated whether particular human leucocyte antigen (HLA) class II genetic polymorphisms contribute to the development of peanut allergy.

METHODS

All individuals from 37 families each containing one or more peanut allergic individuals, plus nine unrelated patients (161 individuals in total, defined as the study group) were typed for the HLA class II DRB1, DQB1 and DPB1 loci, by PCR-based techniques. Genotype frequencies were compared with those found in 293 unrelated controls.

RESULTS

Four class II genotypes (DRB1*08 (13.7% vs 4.8%; Pc = 0.026), DRB1*08/12 tyr 16 (22.4% vs 8.2%; Pc = 0.021), DQB1*04 (12.2% vs 2.7%; Pc = 0.0026) and DPB1*0301 (49.1 vs 22.5%; Pc = 0.00062)) were present at a significantly higher frequency in the study group compared with controls. Three of these genotypes (DRB1*08 (18.0%; Pc = 0.027), DRB1*08/12 tyr16 (24.0%; Pc = 0.029) and DQB1*04 (16.7%; Pc = 0.0029)) were also significantly increased in peanut allergic individuals compared with controls. In addition, two genotypes (DPB1*0101 and 0201) were significantly decreased in frequency in the overall study group, but not specifically in peanut allergic individuals.

CONCLUSION

While other genetic factors may be important, results from this study indicate that HLA class II genetic polymorphism may play a role in determining susceptibility to peanut allergy.