Genetics of human immune response to allergens

Association between HLA Antigens and Birch Pollen Allergy in Japanese Subjects

Birch pollen is a very common cause of nasal allergy (pollinosis) not only in Scandinavia, Europe, Canada, and the northern part of the United States but also in Hokkaido, Japan. Although there are many papers describing the association of HLA antigens and pollinosis caused by many other allergens, there is no report about the association of HLA antigens and birch pollen allergy. In this paper, we performed an HLA population study of birch pollen-allergic patients in Japan and their pattern analysis of HLA-DRB and HLA-DQB gene by the Southern blot hybridization technique. Our population study data indicated that the HLA-DR9 and HLA-DQw3 phenotypes strongly associated with the development of birch pollen allergy in Japanese subjects. By restriction fragment length polymorphism pattern analysis, some restriction fragments of the HLA-DQB gene were detected only in the patient group. These data suggested that there was a significant association between HLA class II antigens and the development of birch pollen allergy in Japanese subjects.

Multiple signaling pathways converge on beta-catenin in thyroid cancer

The beta-catenin pathway has been conclusively demonstrated to regulate differentiation and patterning in multiple model systems. In thyroid cancer, alterations are often seen in proteins that regulate beta-catenin, including those of the RAS, PI3K/AKT, and peroxisome proliferation activated receptor-gamma (PPARgamma) pathways, and evidence from the literature suggests that beta-catenin may play a direct role in the dedifferentiation commonly observed in late-stage disease. RET/PTC rearrangements are frequent in thyroid cancer and appear to be exclusive from mutational events in RAS and BRAF. Activation of AKT by phosphatidylinositide-3 kinase (PI3K), a RAS effector, results in GSK3beta phosphorylation and deactivation and subsequent beta-catenin upregulation in thyroid cancer. Activating mutations in beta-catenin, which have been demonstrated in late-stage thyroid tumors, correlate with beta-catenin nuclear localization and poor prognosis. We hypothesize that activation of the RAS, PI3K/AKT, and PPARgamma pathways ultimately impinges upon beta-catenin. We further propose that if mutations in BRAF, RAS, and RET/PTC rearrangements are mutually exclusive in certain thyroid tumors or tumor types, as has already been shown for papillary thyroid cancer, then these interconnected pathways may cooperate in the initiation and promotion of the disease. We believe that clinical benefit for thyroid cancer patients could be derived from disrupting the middle or distal pathway effectors of these pathways, such as AKT or beta-catenin.

Differences of genetic effects for the development of allergic diseases in two cities of Japan

BACKGROUND

Differences in the effects of genetic factors on allergic diseases in two areas of the same race within the same country have not been studied with multiple logistic regression.

OBJECTIVE

To determine whether the effects of genetic factors on allergic diseases differ between two areas.

METHODS

A questionnaire provided information about family histories of allergic diseases and environmental factors was distributed to children attending kindergarten, elementary, or junior high school in two Japanese cities: Gifu, with a temperate climate, and Itoman, with a subtropical one. The number of subjects analyzed were 1,243 in Gifu and 1,953 in Itoman. Multiple logistic regression analysis was performed with SAS.

RESULTS

Multiple logistic regression analysis showed that in both cities children of families with allergic histories have significantly higher risk of contracting allergic disease and atopic dermatitis, even after being controlled for environmental factors. In Gifu, in families where both parents suffered from allergy, there was a higher incidence of allergic diseases than when only one of the parents was suffering from it. On the other hand, in Itoman there were no differences of relative risk between paternal history and maternal history.

CONCLUSIONS

We speculated that there are some differences of genetic factors between different areas of the same country, and these differences of genetic effects may influence on the difference of the prevalence of allergic diseases as well as the environmental factors.

Latex allergy: a review for the dental professional

Reactions to latex products are reportedly occurring with an increased frequency both in patients and in health care providers. Natural rubber latex is found in numerous products, and adverse latex reactions range from contact dermatitis to life-threatening anaphylaxis. A complete understanding of the pathophysiology of latex allergy provides the foundation for the proper diagnosis and treatment of patients with latex allergy. This article provides the reader with a review of latex allergy and suggests strategies for the management of patients with latex hypersensitivity.

HLA class II genes in soybean epidemic asthma patients

From 1981 to 1987, 26 outbreaks of asthma caused by the inhalation of soybean dust, affecting a total of 688 individuals, were detected in Barcelona, Spain. Because only a small proportion of asthmatic individuals living in Barcelona expressed the epidemic phenotype, it is hypothesized that a genetically determined human leukocyte antigen (HLA) Class II factor could have played a role in the susceptible individuals. Accordingly, we studied the distribution of both HLA-DR and HLA-DQ in soybean epidemic asthmatic patients. An analysis of the HLA-DR and HLA-DQ genes for genetic polymorphisms of the beta 1 chain was done with the polymerase chain reaction (PCR) in 78 soybean epidemic asthma patients, and the findings were compared with those for 67 nonepidemic asthmatic individuals and 168 individuals from the general population. An allelic disequilibrium could be established; the risk of epidemic asthma was particularly associated with the DRB1*13 gene (p value corrected for multiple comparisons < 0.02). The association observed for the DRB1*13 gene was stronger in individuals in the lowest tertile for total IgE, with an estimated risk with a 95% confidence interval (CI), of 14.5 (1.6 to 130.8). The combination of two genes from among the DRB1*05-05, DRB1*05-06, and DRB1*06-06 genes was present in epidemic asthmatic subjects only. No association with an HLA-DQB1 allele could be observed. Genetic predisposition could contribute to the response of some asthmatic patients to exposure to soybean dust, having led to their being affected during the epidemics of asthma in Barcelona.

Effect of maternal lifestyle on cord blood IgE factor

During recent decades much interest has been focused on the possibility of predicting and preventing atopic diseases during pregnancy. The idea of being able to detect a predisposition early and take suitable environmental measures in order to avoid overt allergy is an attractive position. Elevated cord IgE of around 1.0 IU/ml has been proposed as a predictor in western children. However, there remains no information about the effect of maternal lifestyle during pregnancy on these levels. Total IgE levels were therefore determined using Pharmacia CAP system and PRIST, with sensitivities of 0.01 kU/l and 0.25 kU/l, respectively, from serum samples taken from 1138 Japanese pairs of cord blood and pregnant women responding to a questionnaire regarding 17 health practices, intake of 32 food allergens and 5 environmental factors. Of these, 28 (2.5%) pairs of samples were excluded from further analysis because of high contamination of IgA (> 15.4 mg/ml) in cord blood. Median cord blood IgE was 0.286 kU/l and geometric mean IgE was 66.25 kU/l in maternal sera using CAP system; there was no significant correlation between maternal log (IgE) and cord blood IgE. Similar results were obtained from PRIST, whose correlation with CAP system was significant (r = 0.884, p < 0.001 for maternal and r = 0.765, p < 0.001 for cord blood). Multiple logistic analysis demonstrated that avoidance of simultaneous exposure to hens' eggs and cow's milk (relative risk = 1.3, p < 0.05) as well as soy beans (relative risk = 2.8, p < 0.01) should be advised to mothers with positive allergic histories and/or high total IgE (> 400 IU/ml), especially in women aged more than 35 years who are pregnant with a male child. However, maintenance of healthy lifestyles, especially taking proper exercise and sleeping, and avoidance of inhalant allergens during late pregnancy may be a more important strategy for the reduction of cord blood IgE levels.

Inferences from occupational asthma

Occupational asthma-asthma induced by an agent inhaled at work-provides a valid model for the examination of the more general environmental causes of asthma. In many instances, definable populations exposed to a novel allergen in the workplace at concentrations that are relatively easily measured develop IgE-associated asthma and characteristic eosinophilic bronchitis. Carefully designed epidemiological studies suggest that the incidence of IgE antibody and asthma is highest in the first one to two years of exposure; and that the risk is directly related to the intensity of airborne allergen exposure. The relationship between exposure and outcome is modified both by concurrent cigarette smoking and by genotype, although the details of this latter interaction remain unclear. Symptoms, airway hyper-responsiveness and airway inflammation may persist for several years after avoidance of exposure to the initiating agent. If the relevance of the model is accepted then these insights require testing and further investigation, both within the field of occupational asthma and, by extension, in the wider field of asthma in the general environment.

Natural rubber latex allergy: spectrum, diagnostic approach, and therapy

Latex allergy has reached epidemic proportions in the United States and is increasingly recognized as a significant contributor to morbidity and mortality during medical and surgical procedures. Ultimately, many of the affected patients with recognized latex sensitivity and those who are not yet diagnosed will receive treatment for their allergic reactions to latex in emergency departments. Consequently, emergency physicians must have a comprehensive understanding of the etiology, epidemiology, pathogenesis, treatment, and management of these challenging patients. Groups at high risk include spina bifida cystica patients, health care workers, latex industry workers, specific food-allergy patients, and patients with a history of atopy or multiple surgical procedures. Sensitization to latex antigens is commonly encountered in health care workers wearing latex gloves with high latex allergen concentrations and in workers using powdered latex surgical gloves. Exposure to air-borne allergens and water-soluble IgE reactive latex antigens from natural rubber latex products in sensitized individuals can result in type I (immediate) hypersensitivity reactions. Clinical manifestations include contact urticaria, dermatitis, allergic rhinitis, conjunctivitis, asthma, angioedema, and anaphylaxis. Diagnostic tools include serological assays and skin prick testing. At present, latex avoidance is the only available treatment and is the key to preventing allergic reactions in latex-sensitized individuals. Health care worker sensitization to latex antigens in natural rubber products is becoming an increasing contributor to workers' liability and disability claims. Specific action can be taken to reduce occupational and patient exposure to latex antigens.

Association of life style with high risk of hyperimmunity and of immunosuppression mediated by IgE

To test the hypothesis that the increase in allergic prevalence is related not only to environmental allergens, but also to comprehensive life style, we administered to 733 workers at a hard metal plant a questionnaire that included 17 physical and mental health practices. We have shown that eight practices are associated with increases or decreases of total and specific IgE levels, serving to keep them within the normal range (5-400 IU/ml), after controlling for age, sex, and environmental factors. Further confirmation of the definite effect of life style on allergic reactions comes from higher heritability among younger pairs of identical twins of total IgE levels and allergic disorders than among older pairs of identical twins. A marked synergism was found among Undesirable life-style factors as bipolar high-risk factors for the development of allergic diseases or immunosuppression characterized by low natural killer (NK) cell activity through which soluble low-affinity IgE receptor is kept low. An effort to practice Desirable life styles, therefore, may be of benefit in reducing the risk of immunoallergic disorders.

Interfering factors to sensitivity and specificity of bronchial reactivity in children

Bronchial reactivity to carbachol, estimated by the PD65, the provocation dose of inhaled carbachol inducing a 65% increase of baseline respiratory resistance, was measured in 355 asthmatic children (age 8.7 +/- 2.6 years) and 149 healthy children (age 11.8 +/- 2.3 years). The frequency distribution of PD65 showed apart from 2 minima at 480 micrograms and 960 micrograms 2 significant peaks at 240 micrograms (p = 0.003) and 1200 micrograms (p = 0.01) to carbachol, reflecting a hyperreactive class (PD65 < 480 micrograms), an intermediate class (481 micrograms < PD65 < 960 micrograms) and a normo-reactive class (PD65 > 961 micrograms). The intermediate class is characterised by a considerable overlap between "health" and "disease". However, taking into account the degree of air pollution in which healthy children are living (best related factor to specificity) and the type of initial lung function disorder in asthmatic children, (the MEF50 to be the best related factor for specificity), weighed specificity and sensitivity improved from 64 to 88%. Evaluating bronchial responsiveness in children, such interfering factors should be strongly considered.

Biochemical properties of aeroallergens: contributory factors in allergic sensitization?

Recent studies indicate that the majority of clinically important aeroallergens are biochemically active. A diverse range of properties have been demonstrated but most possess either enzymatic activity (principally hydrolytic), enzyme inhibitory activity, low molecular weight ligand transporting or regulatory properties. In addition, some allergens are glycosylated and/or are structurally similar to proteins which have evolved to function in the respiratory system per se. Little attention has been given to the possibility that the biochemical activity of an allergen or any post-translational modifications contribute to sensitization. In this review, mechanisms with the potential to influence immunogenicity are discussed including interaction with respiratory secretions, epithelial disruption, interactions with immunocompetent cells and receptor mediated endocytosis. Given that many aeroallergens are structurally and functionally similar to a variety of endogenous (e.g. lysosomal enzymes) and exogenous proteins (e.g. microbial enzymes and glycoproteins), particular attention has been directed to the latter. This process represents an important non-adaptive defence mechanism which has evolved to recognize and process such proteins and it is feasible that it plays a similar role in the processing of some allergens entering the respiratory system.

Sensitization of asthmatic children to common environmental allergens according to their residence

The medical records of 974 asthmatic children aged 1-14 years (mean 8.7 +/- 3.9 years) who had been evaluated with skin prick tests (SPT) in two referral Children's Hospitals in Athens from 1975 to 1987 were analyzed. The children were grouped according to their residence into groups from urban area (UR), rural area (RU), and coastals (CO). The prevalence of positive SPT and the sensitizing allergens according to the residential area and the family atopic history were considered. It was found that 662/974 (68%) children had positive SPT with 63.6%, 70.7%, and 80.4% in UR, RU, and CO respectively. There was a significant difference in the prevalence of positive SPT between UR and CO. A positive family atopic history was more often accompanied by positive SPT in UR only. Sensitization to grass pollens was noted with higher prevalence in UR. The house dust mite Dermatophagoides pteronyssinus sensitization was more prevalent in CO. Our results support the notion that the environment can influence the prevalence of sensitization to common environmental antigens, the kind of sensitizing allergen, and the expressiveness of the genetic factor with regard to development of atopic asthma.

Lack of linkage between atopy and locus 11q13

Atopy as defined in terms of IgE responsiveness was reported to be controlled by a single gene in British families, and this concept was further supported by a significant linkage between atopy and restriction fragment length polymorphism (RFLP) detected by a DNA probe specific to chromosome 11q13. To confirm this observation in a Japanese population, segregation and linkage analyses were done in four large families. Although segregation patterns of atopy were in agreement with the pattern of autosomal dominant inheritance, there was no significant linkage between atopy and locus 11q13. Alterations in the definitions of atopy did not affect the results. These findings suggested the presence of heterogeneity in genetic elements of atopy, even though atopy may be determined mainly by a single dominant gene.

Genetic 'risk' for atopy is associated with delayed postnatal maturation of T-cell competence

Recent in vitro studies suggest that IgE production in adults is co-ordinately regulated by negative signals from gamma IFN-producing CD4+ T-helper-1 (TH-1) and positive signals from IL-4 producing (TH-2) T-cells. Additionally, seroepidemiological evidence has pinpointed infancy as the period of maximum lifetime risk for T-cell sensitization to ubiquitous environmental antigens. The present study sought to elucidate the relationship between these observations, by examination of CD4+ T-cell function in normal children and those genetically at 'high risk' for atopy, spanning the age range (up to 4 years) in which IgE responses to environmental allergens is typically manifest. Immunocompetent T-cell precursor frequencies (determined by cloning at limiting dilution) were markedly reduced in 'high risk' children relative to normals (0.53 +/- 0.29 vs 0.26 +/- 0.19; P = 0.0025). Consistent with reports from other laboratories employing bulk T-cell culture techniques, the gamma IFN producing capacity of CD4+ T-cell clones from both groups of children were markedly reduced relative to adults, and was lowest in the high risk group (P < 0.02). IL-4 production by CD4+ T-cell clones from the normal children was within the adult range, but again was significantly lower in the high risk group (P < 0.00005). This indicates that initial immune responses to environmental allergens in early childhood occur against a background of maturational 'deficiency' in CD4+ T-cell function, and suggests the possibility that variations in the rate of postnatal maturation of T-cell competence may be a contributing factor in the development of differing patterns of immunological responsiveness to environmental allergens.

Lifestyle effect on total IgE. Lifestyles have a cumulative impact on controlling total IgE levels

Recent studies have demonstrated an increasing number of cases of allergy in economically developed societies. Many of these allergic reactions are mediated by IgE antibodies whose levels are under genetic control. However, this large increase of allergy prevalence cannot be explained by genetic mutations; comprehensive lifestyles may also play roles in determining total IgE levels. Total IgE levels were determined from serum samples taken from 706 hard metal workers who responded to a questionnaire including 17 items related to physical and mental health practices. Five factors tending to normalize IgE upward and three tending to normalize IgE downward when we keep good lifestyles were extracted using MANOVA analysis. We therefore constructed a Health Practice Index in Allergic reactions (HPIA); eight physical and mental health practices were significantly (P less than 0.05) associated with cumulative elevations or suppressions of total IgE levels when sex, age and environmental factors were controlled for. Multivariate analyses demonstrated a dramatic synergism (Relative Risk greater than 2.0, P less than 0.05) of unhealthy lifestyles determining a bipolar high risk for elevated or suppressed IgE levels which in turn may result in allergic diseases or immuno-suppression. Maintenance of healthy lifestyles may prove beneficial for reducing the prevalence of allergic disorders.

Definition and assessment of asthma

Bronchial obstruction, its reversibility, airway hyperreactivity and inflammation are key variables of asthma. In clinical practice they can be assessed with repeated noninvasive lung function measurements (spirometry and mucociliary clearance). The asthmatic inflammation in contrast to chronic bronchitis is characterized by increased IgE and eosinophils depending on the disease state (seasonal, perennial, chronic symptomatic or asymptomatic asthma). Based on the above-mentioned clinically applicable measurements, a classification of asthma, chronic (obstructive) bronchitis, and emphysema is proposed because the three groups of diseases have different etiology and need different prophylactic and symptomatic treatment.

Exposure to house-dust mite allergen (Der p I) and the development of asthma in childhood. A prospective study

BACKGROUND AND METHODS

Children with asthma commonly have positive skin tests for inhaled allergens, and in the United Kingdom the majority of older children with asthma are sensitized to the house-dust mite. In a cohort of British children at risk for allergic disease because of family history, we investigated prospectively from 1978 to 1989 the relation between exposure to the house-dust mite allergen (Der p I) and the development of sensitization and asthma.

RESULTS

Of the 67 children studied in 1989, 35 were atopic (positive skin tests), and 32 were nonatopic. Of the 17 with active asthma, 16 were atopic (P less than 0.005), all of whom were sensitized to the house-dust mite, as judged by positive skin tests and levels of specific IgE antibodies (P less than 0.001). For house-dust samples collected from the homes of 59 of the children in 1979 and from 65 homes in 1989, the geometric means for the highest Der p I exposure were, respectively, 16.1 and 16.8 micrograms per gram of sieved dust. There was a trend toward an increasing degree of sensitization at the age of 11 with greater exposure at the age of 1 (P = 0.062). All but one of the children with asthma at the age of 11 had been exposed at 1 year of age to more than 10 micrograms of Der p I per gram of dust; for this exposure, the relative risk of asthma was 4.8 (P = 0.05). The age at which the first episode of wheezing occurred was inversely related to the level of exposure at the age of 1 for all children (P = 0.015), but especially for the atopic children (r = -0.66, P = 0.001).

CONCLUSIONS

In addition to genetic factors, exposure in early childhood to house-dust mite allergens is an important determinant of the subsequent development of asthma.

Association of HLA-DR3 with human immune response to Lol p I and Lol p II allergens in allergic subjects

Associations between HLA type and IgE or IgG antibody (Ab) responses to two well-characterized, antigenetically non-crossreactive components of Lolium perenne (rye grass) pollen extract, Lol p I (Rye I) and Lol p II (Rye II) were studied in two groups of skin-test positive (ST+) Caucasoid adults. By both nonparametric and parametric statistical methods, significant associations were found between Ab responses to both Lol I and Lol II and the possession of HLA-DR3. In view of the well-known associations of both DR3 and B8 (which are in linkage disequilibrium) with many autoimmune diseases, differences in anti-Lol I and anti-Lol II mean log[Ab] levels between B8+, DR3- vs B8-, DR3- subjects and B8+, DR3+ vs B8-, DR3+ subjects were investigated. No differences were found. Our data, along with recent RFLP and DNA sequence studies, suggest that an Ia molecule involved in immune recognition of a similar major Ia recognition site of both the Lol molecules may consist of a DR3 alpha-beta I pair. Abbreviations used: Ab: Antibody. HLA: Human leukocyte antigen. Lol p I, Lol I: Group I allergen from Lolium perenne pollen (Rye I). Lol p II, Lol II: Group II allergen from Lolium perenne pollen (Rye II). Mr: Relative molecular mass. Rx: Immunotherapy with grass pollen extracts. ST: Skin test.

Human castor bean allergy and HLA-A, B, C, DR

Our results in 27 castor bean-allergic patients typed for HLA-A, B, C, DR antigens show (although the observed difference did not reach a statistical significance after correction for the number of tested specificities) an increase of A2 cross-reacting group antigens and, on the other hand, of HLA-A29, B39, CW2, B12, DR2, and especially DR5 (48.1% vs. 26.9% - chi 2 = 5.579; uncorrected p: 0.01 less than p less than 0.02), which possibly participate in haplotypic combinations. The facts that the markers of the haplotype segments involved are more frequent in northern European populations (e.g., A3,B7--Scandinavian; A29,B12--English) and that regional haplotypes are decreased (e.g., A11,B35) suggest that the allergics could in some geographical areas be less genetically adapted to their environment. In the same way, the fact that although the global number of assigned HLA antigens was increased, the percentage of only some alleles (among these those belonging to the A2-CREG) was increased suggests not only a recessive model but a diminution of the polymorphism in allergics. This is in agreement with the physiological role of the HLA system, the polymorphism of which, according to the numerous restriction phenomena allowed at the cellular level, represents broad possibilities of adapted immune response in man. In any event, these findings clearly suggest that HLA-DR5 and B39 may be the markers of castor bean allergy in the Mediterranean area, to which are superimposed the HLA alleles linked to the general atopic susceptibility.

Demonstration of a common major gene with pleiotropic effects on immunoglobulin E levels and allergy

Atopic disease is generally recognized to be familial, although specific genetic components have yet to be identified. High levels of a unique class of immunoglobulins, immunoglobulin E (IgE), have been shown to be associated with allergies. Several investigators have reported evidence indicating a recessive regulatory locus where an individual with the homozygous recessive genotype has persistently elevated levels of IgE. Willcox and Marsh [1978] have proposed a hypothesis relating IgE production and liability to become allergic. A test of this hypothesis was carried out in the present study. Bivariate segregation analysis of IgE levels and allergy was performed on 173 nuclear families, and the results indicate that an IgE regulatory locus contributes to the familial transmission of allergy. The results are further discussed in the context of the Willcox and Marsh hypothesis.

Genetic analysis of allergic disease in twins

One hundred seven pairs of twins, sixty-one MZT and forty-six DZT, were investigated for allergic disease by a questionnaire, reaginic antibody levels, bronchial reactivity to inhaled methacholine, and skin test responses. Intrapair correlation coefficients (ri) of measured clinical markers of atopy were determined and a heritability analysis was performed. The intrapair correlation coefficient for serum IgE was 0.82 for MZT and 0.52 for DZT. The methacholine area demonstrated greater correlation in MZT with an ri of 0.67 compared to 0.34 for DZT. The total ISTS had an intrapair correlation coefficient of 0.82 in MZT and 0.46 in DZT. Our analysis demonstrates that methacholine sensitivity, total serum IgE levels, and total skin test scores to be heritable traits and suggests a genetic contribution to their expression.

Environmental and social influences on skin test results in children

Skin tests with 13 inhalant allergens were performed in 788 children with respiratory allergy. Positive reactions were common to animal danders (65%), to grass pollens (55%) and to tree pollens (44%) but rare to moulds (13%) and to house dust mite (12%). Children exposed to cows, dogs or horses at home more often had skin test reactions to these allergens than the children not exposed, but reactions to cat dander occurred as frequently in children exposed to cats at home as to those not exposed. Reactions to three pollens occurred most often in children from upper social classes and from urban areas and reactions to house dust mite occurred most often in children from lower social classes and from rural areas. Children with positive reactions to house dust mite came from larger families than children with negative test results.

HLA-Dw2: a genetic marker for human immune response to short ragweed pollen allergen Ra5. II. Response after ragweed immunotherapy

After artificial immunization (immunotherapy) with ragweed antigens, specific immunoglobulin G (IgG) antibody (Ab) response to Ra5 was significantly associated with HLA-Dw2 (P less than 0.0001). From a total of 61 treated patients, all 22 Dw2+ subjects made good IgG Ab responses to Ra5 by year 2 of therapy (21 by year 1), even though 8 of them had no detectable IgG Ab and 9 had no detectable IgE Ab before therapy. The prevalence of IgG Ab response among 39 Dw2- subjects was markedly lower; only 11 (28%) responded well after 1-9 yr of therapy. Both by univariate and multivariate statistical analysis, Dw2 was also found to be strongly associated with the quantity of IgG Ab produced. In particular, both the strength and significance of the association between Dw2 and log[IgG Ab] response to Ra5 increased over a 3-yr period of ragweed therapy (P = 10(-9) by year 3). Multiple regression analysis also revealed a weak association with HLA-B13, which became apparent only after year 2 of therapy. Genetic hypotheses for these findings are discussed. In particular, the possibility of a second Ir gene, Ir-Ra5', separate from HLA-Dw2 and possibly located elsewhere in the genome, is considered.

HLA-Dw2: a genetic marker for human immune response to short ragweed pollen allergen Ra5. I. Response resulting primarily from natural antigenic exposure

Ultra-pure short ragweed pollen allergen Ra5 (5,000 mol wt) was used to investigate the relationship between human leukocyte antigen (HLA) type and IgE and IgG antibody (Ab) responses to Ra5 in two groups of Caucasian subjects, totaling 447 people. Using highly sensitive radioimmunoassay procedures to measure serum IgE and IgG Ab, qualitative responses to Ra5 in both groups were found to be strongly associated with HLA-Dw2 (P less than 0.0001). For example, 95% of 38 people with IgE Ab vs. 22% of 139 ragweed-allergic persons having no detectable IgE Ab to Ra5 were Dw2+. Quantitative log [IgE Ab] and log[IgG Ab] responses to Ra5 were highly correlated with Dw2 (P = 10(-5) to 10(-14)) in four separate multiple regression analyses, examining the relationship between HLA type (and other variables) and Ab levels in the two study groups. Further studies showed that the primary association of Ra5 response was with Dw2 rather than DR2 and that various combinations of A3, B7, and Dw2 were less strongly associated than Dw2 alone.

The association of an HLA 'asthma-associated' haplotype and immediate hypersensitivity in familial asthma

Fifty-seven members from ten families in which one parent and at least one child have asthma were studied with dilutional skin tests and RAST to grass pollens after determination of HLA haplotypes. We found no direct evidence for linkage of a hypothetical asthma locus with HLA or for a significant association of asthma with HLA haplotypes. Linkage between the HLA loci and a gene or genes which allow for the expression of clinical asthma could neither be proven nor disproven due to the small sample size. All of the asthmatic children had positive dilutional skin tests and RAST, suggesting that atopic asthma may be genetically controlled by the HLA chromosome (chromosome 6). Nonetheless, determination of the histocompatibility antigens can increase the value of predictive risk analysis for asthma. Such a determination may be important in the early identification of a child born to a family with atopic asthma.

125I-Clq-binding and specific antibodies as indicators of pulmonary disease activity in cystic fibrosis

We studied the incidence and levels of circulating immune complexes by the 125I-Clq-binding assay in patients with cystic fibrosis in relation to clinical respiratory status and specific IgG and IgE antibodies to Pseudomonas aeruginosa. Staphylococcus aureus, Aspergillus fumigatus, and Candida albicans. Overall prevalence of CIC was 43%, but 86% of serially studied patients had evidence of CIC at some time. Patients with acute respiratory exacerbations and deteriorating pulmonary function had a higher incidence of CIC (76%) as compared to stable patients (36%, P less than 0.01), as well as significantly higher levels of CIC. Acute exacerbations were also associated with significant increases in IgG antibody to Pseudomonas (P less than 0.005) but not in other antibodies. CIC did not correlate with Pseudomonas-specific IgG nor with any other specific antibody studied. A variety of age-related differences in specific antibody levels were seen. The episodic appearance of CIC is common in CF and is usually associated with exacerbation of lung disease.