Analysis of the phenotypic distribution of HLA class I and class II in atopic and non-atopic asthma patients

Allergic and Nonallergic Asthma Have Distinct Phenotypic and Genotypic Features

BACKGROUND

Identification of asthma phenotypes enables a better understanding and management of this heterogeneous disease. Studies have reported associations between human leukocyte antigens (HLA) and asthma in different populations, but the results have been inconclusive and they have rarely considered the distinct disease phenotypes. Our objective was to characterize allergic and nonallergic asthma phenotypes and evaluate possible associations with the HLA system.

METHODS

A total of 109 patients with asthma were prospectively followed during 2 years. They were divided into 2 groups, i.e., allergic and nonallergic asthma, according to their clinical history and skin prick test and serum-specific immunoglobulin E (IgE) results. The control group comprised 297 deceased donors of solid organs. Patients' features and HLA class I and II genotypes were assessed and compared.

RESULTS

This study showed different features between asthma phenotypes. Nonallergic patients were older at the onset of asthma symptoms and had a higher rate of intolerance to nonsteroidal anti-inflammatory drugs. Allergic patients had higher total serum IgE levels, reported atopic dermatitis and rhinoconjunctivitis more frequently, and, unexpectedly, had a greater disease severity. New associations between the HLA genotypes and allergic and nonallergic asthma were identified. The HLA-B*42, HLA-C*17, HLA-DPA1*03, and HLA-DPB1*105 genotypes were associated with allergic asthma and the HLA-B*48 genotype with the nonallergic phenotype. The presence of the haplotype HLA-DPA1*03 DQA*05 was associated with allergic asthma, and the presence of HLA-DPA1*03 and the absence of HLA-DQA*05 with nonallergic asthma.

CONCLUSIONS

Allergic and nonallergic asthma have distinct phenotypic and genotypic features. New associations between asthma phenotypes and HLA class I and II were identified.

HLA and asthma phenotypes/endotypes: a review

Asthma is a complex chronic inflammatory disease of the airways caused by the interaction of genetic susceptibility with environmental influences. Genome-wide association studies (GWAS) represent the most powerful approach for asthma, that have identified several genes (e.g., IL18R1, IL33, SMAD3, ORMDL3, HLA-DQ and IL2RB loci). HLA super-locus is a genomic region in the chromosomal position 6p21. Since no gene can be considered as an asthma gene, able to reflect the complex etiology and the heterogeneity of the disease the terms 'phenotype' and more recently 'endotype' have been used. This review, according to literature availability, focuses on the relationship between human leukocyte antigens (HLA) region specifically the HLA class II genes and different asthma phenotypes/endotypes, such as allergic asthma/Th2 associated, occupational and aspirin-sensitive asthma. The most common HLA haplotypes in the different asthma phenotypes are HLA-DRB1in allergic asthma, HLA-DQB1in occupational asthma and HLA-DPB1 in aspirin-sensitive asthma. However, it is difficult to study the role of class II genes in vivo because of the heterogeneity of human population, the complexity of MHC, and the strong linkage disequilibrium among different class II genes. Despite the variation and the inconsistency of the HLA haplotypes and alleles in different types of asthma, the association between HLA class II genes and asthma has been demonstrated in the majority of studies.

Associations of HLA-A, HLA-B and HLA-C alleles frequency with prevalence of herpes simplex virus infections and diseases across global populations: implication for the development of an universal CD8+ T-cell epitope-based vaccine

A significant portion of the world's population is infected with herpes simplex virus type 1 and/or type 2 (HSV-1 and/or HSV-2), that cause a wide range of diseases including genital herpes, oro-facial herpes, and the potentially blinding ocular herpes. While the global prevalence and distribution of HSV-1 and HSV-2 infections cannot be exactly established, the general trends indicate that: (i) HSV-1 infections are much more prevalent globally than HSV-2; (ii) over a half billion people worldwide are infected with HSV-2; (iii) the sub-Saharan African populations account for a disproportionate burden of genital herpes infections and diseases; (iv) the dramatic differences in the prevalence of herpes infections between regions of the world appear to be associated with differences in the frequencies of human leukocyte antigen (HLA) alleles. The present report: (i) analyzes the prevalence of HSV-1 and HSV-2 infections across various regions of the world; (ii) analyzes potential associations of common HLA-A, HLA-B and HLA-C alleles with the prevalence of HSV-1 and HSV-2 infections in the Caucasoid, Oriental, Hispanic and Black major populations; and (iii) discusses how our recently developed HLA-A, HLA-B, and HLA-C transgenic/H-2 class I null mice will help validate HLA/herpes prevalence associations. Overall, high prevalence of herpes infection and disease appears to be associated with high frequency of HLA-A(∗)24, HLA-B(∗)27, HLA-B(∗)53 and HLA-B(∗)58 alleles. In contrast, low prevalence of herpes infection and disease appears to be associated with high frequency of HLA-B(∗)44 allele. The finding will aid in developing a T-cell epitope-based universal herpes vaccine and immunotherapy.

Influence of asthma epidemiology on the risk for other diseases

Asthma is a multifactorial chronic disease affecting a significant proportion of people in the United States and worldwide. Numerous laboratory and epidemiological studies have attempted to understand the etiology and underlying mechanisms of asthma and to identify effective therapies. However, the impact of asthma on the risk for other diseases has drawn little attention. This paper discusses the potential effects of asthma as a risk factor for other diseases, explores the potential mechanisms, and reviews the implications of the findings to clinical practice, public health, and research.

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.

Human leukocyte antigen type and progression from onset of symptoms to development of asthma

This study investigated the influence of human leukocyte antigen (HLA) genes on the progression of asthma, from the initial onset of symptoms to when criteria for asthma are met. Study subjects were a subsample (n = 340) of 838 healthy children, aged 5-12 years, who participated in a previous study, and who had HLA data and asthma status. The duration in time from the initial onset of asthma symptoms documented in each subject's medical records to the index date when the subject first met criteria for asthma was determined. The time duration was compared between carriers and noncarriers of HLA genes of interest of the 340 original subjects with HLA data available, 114 children (33.5%) met criteria for asthma before 18 years of age. The median ages at onset of asthma symptoms and at the index date of asthma were 4.4 years and 7.2 years, respectively. The median time intervals between onset of symptoms and index date for HLA DRB1*11 carriers and noncarriers were 552 versus 61 days, respectively (p = 0.004). The same time intervals for HLA DQB1*0301 carriers and noncarriers were 420 versus 59 days, respectively (p = 0.012). However, HLA DQB1*0302 or DRB1*03 carriers had shorter median intervals, when compared with noncarriers (119 versus 266 days, respectively, p = 0.20; and 86 versus 258 days, respectively, p = 0.38) but they did not reach statistical significance. HLA type appears to influence the progression of asthma from initial symptoms to disease. Thus, genetic factors may affect the natural history of asthma.

CCL5/RANTES chemokine gene promoter polymorphisms are not associated with atopic and nonatopic asthma in a Spanish population

CCL5/RANTES, a member of the C-C chemokine family, is a potent eosinophil, monocyte, basophile and lymphocyte chemo-attractant at the site of inflammation. Recent studies revealed that a functional mutation at the -403 position in the promoter may have significance for atopic dermatitis, bronchial asthma, sarcoidosis, rheumatoid arthritis and HIV infection, and others. Another polymorphism in the -28 position has been reported. Our objective was to investigate the possible influence of the CCL5/RANTES promoter polymorphisms in the different types of bronchial asthma. CCL5/RANTES genotyping was performed by polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) in 306 asthmatic patients with non-atopic (n = 145) and atopic (n = 161) asthma and 242 controls. The 81.9% of the atopic asthma patients for -403G/A had the G allele and the A allele frequency was 18%. Of the non-atopic asthma patients, the G allele frequency was 79.7% and the A allele was 20.3%. Concerning the -28C/G polymorphism, the frequency of the CCL5/RANTES -28G allele in our patients is 2.8%, which is similar to Spanish adult population. After comparing patients with asthma, atopic patients, non-atopic patients and control population, we found no significant deviation in the distribution of the alleles or genotypes of CCL5/RANTES promoter polymorphisms in any tested comparison. Therefore, human CCL5/RANTES gene promoter polymorphisms are not associated with the different types of bronchial asthma in Spanish population.

Proteomic analysis of peripheral T-lymphocytes in patients with asthma

BACKGROUND

Asthma is chronic airway inflammation that occurs together with reversible airway obstruction. T-lymphocytes play an important role in the pathogenesis of asthma. Proteomic technology has rapidly developed in the postgenomic era, and it is now widely accepted as a complementary technology to genetic profiling. We investigated the changes of proteins in T-lymphocytes of asthma patients by using standard proteome technology: two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and a database search.

METHODS

The proteins of CD3+ T-lymphocytes were isolated from whole blood of six steroid-naive asthmatic patients and of six healthy volunteers. 2D-PAGE was performed and the silver-stained protein spots were comparatively analyzed between the asthma and control groups using an image analyzer. Some differentially expressed spots were identified by MALDI-TOF-MS and database search. The messenger RNA expressions of some identified proteins were examined by real-time polymerase chain reaction (RT-PCR).

RESULTS

Thirteen protein spots in the T-lymphocytes of the asthmatic patients were increased and 12 spots were decreased compared to those of the normal subjects. Among the identified proteins, the increased expression of the messenger RNA of phosphodiesterase 4C and thioredoxin-2 and the decreased expression of the messenger RNA of glutathione S-transferase M3 were confirmed by RT-PCR in the asthmatic patients.

CONCLUSIONS

Proteomic examination of the peripheral T-lymphocytes revealed some differentially expressed proteins in the asthmatic patients. The possibility of using the differentially expressed proteins as important biomarkers and therapeutic targets in asthma patients warrants further studies.

Severity of childhood asthma and human leukocyte antigens type

We sought to learn if Class II HLA genes are associated with the severity of asthma in children. We examined a previously recruited cohort of 340 healthy children who had Class II HLA allele data available. We conducted a comprehensive review of their medical records to determine asthma status and, when present, its severity. We found that Class II HLA alleles, which were previously reported to have an association with asthma incidence, appear to have an association as well with asthma severity. These data support our hypothesis that both the incidence and severity of asthma are heritable and that HLA may play an important role in both development and severity of asthma. Because of limited statistical power, our study findings are subject to further investigation.

Childhood asthma and human leukocyte antigen type

Little is known about the relationship between human leukocyte antigen (HLA) class II genes and family history of asthma or atopy in relation to the incidence of childhood asthma. The objective of the study was to determine whether specific HLA class II genes (e.g., DRB1*03) are associated with asthma and whether such association explains the influences of family history of asthma or atopy on asthma incidence. A stratified random sample of 340 children who had HLA data available from the Rochester Family Measles Study cohort (n= 876) and a convenience sample of healthy children aged 5-12 years were the participants. We conducted comprehensive medical record reviews to determine asthma status of these children. The associations between the presence of specific HLA alleles and development of asthma and the role of family history of asthma or atopy in the association were evaluated by fitting Cox models. The cumulative incidence of asthma by 12 years of age among children who carry HLA DRB1*03 was 33%, compared to 24.2% among those who did not carry this allele. Adjusting for family history of asthma or atopy, gender, low birth weight, season of birth, HLA DRB1*04, and HLA DQB1*0302, the hazards ratio for HLA DRB1*03 carriers was 1.8 (95% confidence interval: 1.1-2.9, P= 0.020). We concluded that the HLA DRB1*03 allele is associated with asthma. However, the HLA class II gene does not explain the influences of family history of asthma or atopy on development of asthma. The mechanism underlying the association between asthma and HLA genes needs to be elucidated.

Childhood asthma and measles vaccine response

BACKGROUND

Asthmatic patients have a TH2-predominant milieu that is associated with humoral immunity. However, little is known about whether humoral immune responses to viral antigens differ between asthmatic and nonasthmatic children.

OBJECTIVE

To determine whether humoral immune response differs in asthmatic patients vs nonasthmatic patients.

METHODS

Measles virus specific IgG antibody levels were determined for the Rochester Family Measles Study cohort (n = 876), a convenience sample of healthy children 5 to 12 years of age in Rochester, MN. We conducted comprehensive medical record reviews of 838 children who were eligible for this study. We determined the child's asthma status at the time of determination of antibody levels by applying predetermined criteria for asthma. Comparisons were made using the 2-sample t test or chi2 test.

RESULTS

Of the 838 children, 156 (18.6%) had asthma at the time of the determination of antibody levels and were not taking systemic steroids within 14 days of specimen collection. Among those with a nonequivocal antibody reading, the seropositive response rates were similar in asthmatic patients and nonasthmatic patients (89.7% vs 90.3%, respectively; P = .83). However, the equivocal response rates were slightly higher among asthmatic patients than nonasthmatic patients (6.4% vs 4.7%, respectively).

CONCLUSION

Asthmatic children seem to have similar humoral immune responses to measles vaccine as those without asthma. Although the findings reassure health care practitioners, whether this finding is generalizable to other vaccines and whether asthmatic patients with low antibody levels have normal cell-mediated immunity need to be elucidated in future studies.

Human leucocyte antigen-C in B chronic lymphocytic leukaemia

This study aimed at characterising the distribution of human leucocyte antigen (HLA)-C alleles in a large group of patients with B chronic lymphocytic leukaemia from Southeastern Spain. Ninety-eight adult patients and 194 geographically and ethnically matched controls were studied. HLA-C was determined by polymerase chain reaction sequence-specific primers (PCR-SSP) and PCR-sequence-specific oligonucleotides (SSO) methods. The HLA-Cw*16 allele frequency was found to be significantly increased amongst patients compared with controls in our population (27.6% vs. 12.4%, P = 0.0012, Pc = 0.016). HLA-C dimorphism was also analysed but no association was found.

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.

Current concepts on the genetics of asthma

Asthma is a complex genetic disorder with variable phenotype, largely attributed to the interactions of the environment and multiple genes, each potentially having small effects. Numerous asthma and atopy loci have been reported in studies demonstrating associations and/or linkage of the asthma-associated phenotypes, atopy, elevated IgE levels, and bronchial hyperresponsiveness to alleles of microsatellite markers and single nucleotide polymorphisms within specific cytokine/chemokine and IgE regulating genes. Although the studies reporting these observations are compelling, most of them lack statistical power. This review compiles the evidence that supports linkage and associations to the various genetic loci and candidate genes. Whereas significant progress has been made in the field of asthma genetics in the past decade, the roles of the genes and genetic variations within the numerous candidate asthma genes that have been found to associate with the expression of the asthmatic phenotype remain to be determined.