Clinical Phenotypes of Atopy and Asthma in COPD: A Meta-analysis of SPIROMICS and COPDGene.

BACKGROUND: Little is known about the concordance of atopy with asthma COPD overlap. Among individuals with COPD, a better understanding of the phenotypes characterized by asthma overlap and atopy is needed to better target therapies. RESEARCH QUESTION: What is the overlap between atopy and asthma status among individuals with COPD, and how are categories defined by the presence of atopy and asthma status associated with clinical and radiologic phenotypes and outcomes in the Genetic Epidemiology of COPD Study (COPDGene) and Subpopulation and Intermediate Outcome Measures in COPD Study (SPIROMICS)? STUDY DESIGN AND METHODS: Four hundred three individuals with COPD from SPIROMICS and 696 individuals from COPDGene with data about specific IgEs to 10 common allergens and mixes (simultaneous assessment of combination of allergens in similar category) were included. Comparison groups were defined by atopic and asthma status (neither, atopy alone, atopic asthma, nonatopic asthma, with atopy defined as any positive specific IgE (≥0.35 KU/L) to any of the 10 allergens or mixes and asthma defined as self-report of doctor-diagnosed current asthma). Multivariable regression analyses (linear, logistic, and zero inflated negative binomial where appropriate) adjusted for age, sex, race, lung function, smoking status, pack-years smoked, and use of inhaled corticosteroids were used to determine characteristics of groups and relationship with outcomes (exacerbations, clinical outcomes, CT metrics) separately in COPDGene and SPIROMICS, and then adjusted results were combined using meta-analysis. RESULTS: The prevalence of atopy was 35% and 36% in COPD subjects from SPIROMICS and COPDGene, respectively, and less than 50% overlap was seen between atopic status with asthma in both cohorts. In meta-analysis, individuals with nonatopic asthma had the most impaired symptom scores (effect size for St. George's Respiratory Questionnaire total score, 4.2; 95% CI, 0.4-7.9; effect size for COPD Assessment Test score, 2.8; 95% CI, 0.089-5.4), highest risk for exacerbations (incidence rate ratio, 1.41; 95% CI, 1.05-1.88) compared with the group without atopy or asthma. Those with atopy and atopic asthma were not at increased risk for adverse outcomes. INTERPRETATION: Asthma and atopy had incomplete overlap among former and current smokers with COPD in COPDGene and SPIROMICS. Nonatopic asthma was associated with adverse outcomes and exacerbation risk in COPD, whereas groups having atopy alone and atopic asthma had less risk.

Beneficial role of endogenous immunoglobulin subclasses and isotypes in septic shock.

PURPOSE: There is increasing evidence on the relationship between endogenously produced immunoglobulins and the clinical outcome in septic shock (SS). MATERIALS AND METHODS: Levels of immunoglobulin G (IgG) subclasses, immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin E were measured in plasma from 42 patients with SS and in 36 patients with systemic inflammatory response syndrome at diagnosis. Association of immunoglobulins levels with disease severity and outcome was evaluated. RESULTS: Eighteen patients with SS finally died. Both patients with systemic inflammatory response syndrome and SS showed subnormal levels of total IgG, IgG2, and IgM. Patients with SS who died showed the lowest levels of total IgG and IgG1. Total IgG, IgG1, IgG2, IgG3, IgG4, and IgA correlated inversely with Acute Physiology and Chronic Health Evaluation II score in SS. Univariate Cox regression analysis showed that levels of IgG1, IgG2, IgG3, IgM, IgA, and total IgG were inversely associated to the probability of death at 28 days. Multivariate analysis showed that IgG1, total IgG, IgM, and IgA behaved as independent protective factors against mortality (hazard ratio, P): 0.23, 0.026; 0.16, 0.028; 0.11, 0.042; 0.05, 0.010, respectively, whereas IgG3 showed a protective trend also. CONCLUSIONS: Our study evidenced that, in addition to IgG1, other major endogenous immunoglobulins isotypes and subclasses seem to play a beneficial role in SS.

[Classification of specific IgE antibodies in children with hay fever and other atopic diseases in Germany. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]. / Sensibilisierungsstatus bei Kindern und Jugendlichen mit Heuschnupfen und anderen atopischen Erkrankungen. Ergebnisse aus dem Kinder- und Jugendgesundheitssurvey (KiGGS).

The dependencies between sensitization to common allergens (mono- and polysensitization, IgE level and patterns) and symptomatic hay fever and other atopic diseases, respectively, in children and adolescents are shown in this analysis. The evaluation was based on the KiGGS ("Kinder- und Jugendgesundheitssurvey") study. Our analysis was performed using complex samples methods with SPSS. Participants were interviewed by a physician using a validated questionnaire asking for atopic diseases and symptoms. Specific IgE levels were measured from the age of 3 years on by using the ImmunoCap® test system. The prevalences of hay fever and polysensitizations both significantly increase with increasing age of the participants, while boys are more often affected than girls and migrants less often regarding sensitizations. Prevalence of hay fever decreases with increasing number of older siblings and increases with atopy of one or both parents. Different positive correlations between increasing IgE levels and hay fever were identified, the greatest association was observed with herbal inhalative allergens and cross-reacting food allergens. Lowest IgE levels to nearly all of the tested allergens show a positive correlation with hay fever prevalence. In conclusion, the study indicates that the clinical definition of the lowest positive IgE levels as "marginal" should be discussed as well as indications for specific immunotherapy.

Profile of anti-Leishmania antibodies related to clinical picture in canine visceral leishmaniasis.

This research investigated the profile of anti-Leishmania antibodies in different clinical forms of canine visceral leishmaniasis (CVL). Naturally infected dogs were divided into two groups: subclinical dogs (SD, n=10) and clinical dogs (CD, n=68). Non-infected dogs (ND, n=7) comprised the negative control group. The humoral response was evaluated by the profile of total IgG, IgG1, IgG2, IgM, IgA and IgE, determined by ELISA. Infected animals showed increased levels of total IgG, IgA and IgE in addition to IgG1 and IgG2 in groups SD and CD, when compared with group ND. Furthermore, it was observed that IgG2 and IgM were correlated with symptomatology, while total IgG, IgG1 and IgA were negatively correlated and IgE showed no correlation. It follows that serum levels of IgG2 anti-Leishmania are correlated with typical clinical signs of disease. Furthermore the determination of specific anti-Leishmania antibodies could be an important tool in monitoring CVL clinical picture.

IgE transcripts in the circulation of allergic children reflect a classical antigen-driven B cell response and not a superantigen-like activation.

Allergic asthma is the most frequent chronic disorder in childhood. Although IgE is a central effector molecule in allergic diseases, the nature of the IgE response is still under debate. The objective of our study was to clarify whether the IgE repertoire in the circulation of allergic children represents a classical Ag-driven and oligoclonal B cell response, a superantigen-like activation of a subset of B cells, or a polyclonal B-1 cell expansion. Using a highly sensitive RT-PCR method, we amplified, cloned, and sequenced IgE H chain transcripts from 13 children with allergic asthma. We gained 1366 functional IgE sequences, which currently represent the most extensive collection of human IgE transcripts. Compared to IgM transcripts from the same children, the somatic mutation rate was significantly enhanced in IgE transcripts (21 per thousand versus 72 per thousand; p < 0.001), which renders a polyclonal B-1 response unlikely. Moreover, IgE sequences displayed significantly enhanced Ag selection and hence were indicative of a classical Ag-driven immune response with affinity maturation (p < 0.001). In contrast to several recent studies, the usage pattern of variable gene segment of the H Ig chain in IgE transcripts followed the germline complexity, arguing against a superantigen-like interaction. We conclude that IgE transcripts in the circulation of children with allergic asthma reflect a classical adaptive B-2 cell response. This study provides reference data for a better characterization of the IgE response under immunomodulating therapies, such as anti-IgE therapy or allergen-specific immunotherapy.

IgE sensitization to fungi mirrors fungal phylogenetic systematics.

BACKGROUND: Fungal allergy is an elusive disease, and little progress has been made in this field during recent years. Moreover, because of the complexity of the organisms, it is difficult to categorize fungi systematically on the basis of morphologic characterization. However, recent molecular phylogenetics studies have substantially improved fungal categorization. In parallel, new approaches to analyze large IgE antibody datasets enable identification and visualization of IgE sensitization patterns. OBJECTIVE: To study whether molecular phylogenetic relationships of fungal species, commonly used in allergy diagnosis, also are reflected in IgE sensitization profiles of individuals sensitized to fungi. METHODS: A dataset was compiled of recorded serum IgE antibody levels to 17 different fungal species from 668 individuals sensitized to at least 1 of the 17 species. By applying a clustering method to this dataset, the fungal species were grouped into a hierarchical organization. Finally, the resulting organization was compared with recently published fungal systematics. RESULTS: The hierarchical structure of fungi, based on the presence of IgE antibodies in sensitized individuals, very well reflected phylogenetic relationships. Examples include the distinct separation of basal fungi from the subkingdom Dikarya as well as individual cluster formations of fungi belonging to the subphylum Saccharomycotina and order Pleosporales. CONCLUSION: To our knowledge, this is the first in-depth study that demonstrates a close relationship between molecular fungal systematics and IgE sensitization to fungal species. Because close evolutionary organisms typically have a higher degree of protein similarity, IgE cross-reactivity is likely the main reason for obtained organization.

Impact of the IL-4 -590 C/T transition on the levels of Plasmodium falciparum specific IgE, IgG, IgG subclasses and total IgE in two sympatric ethnic groups living in Mali.

This study aimed to examine the effect of IL-4 -590 T/C polymorphism on the levels of malaria-specific IgE, IgG, IgG (1-4) subclasses as well as total IgE in the Fulani and their sympatric ethnic group, the Dogon, in Mali. Asymptomatic individuals, of the Fulani and the Dogon ethnic groups, were included in the study. IL-4 is involved in the regulation of IgE and IgG4 subclass. In line with this we found that within the Fulani, the T allele was associated with increased levels of total and anti-malarial IgE (P=0.02 and P=0.04, respectively). The Fulani T allele carriers had slightly higher levels of malarial specific IgG4 as compared to those with the CC genotype (P=0.08). No such differences were observed amongst the Dogon individuals. Taken together, these data indicate that the impact of IL-4 -590 variants on antibody levels may vary in different ethnic populations, and that this might affect the Ig-class and subclass distributions.

Comprehensive 3D-modeling of allergenic proteins and amino acid composition of potential conformational IgE epitopes.

Similarities in sequences and 3D structures of allergenic proteins provide vital clues to identify clinically relevant immunoglobulin E (IgE) cross-reactivities. However, experimental 3D structures are available in the Protein Data Bank for only 5% (45/829) of all allergens catalogued in the Structural Database of Allergenic Proteins (SDAP, http://fermi.utmb.edu/SDAP). Here, an automated procedure was used to prepare 3D-models of all allergens where there was no experimentally determined 3D structure or high identity (95%) to another protein of known 3D structure. After a final selection by quality criteria, 433 reliable 3D models were retained and are available from our SDAP Website. The new 3D models extensively enhance our knowledge of allergen structures. As an example of their use, experimentally derived "continuous IgE epitopes" were mapped on 3 experimentally determined structures and 13 of our 3D-models of allergenic proteins. Large portions of these continuous sequences are not entirely on the surface and therefore cannot interact with IgE or other proteins. Only the surface exposed residues are constituents of "conformational IgE epitopes" which are not in all cases continuous in sequence. The surface exposed parts of the experimental determined continuous IgE epitopes showed a distinct statistical distribution as compared to their presence in typical protein-protein interfaces. The amino acids Ala, Ser, Asn, Gly and particularly Lys have a high propensity to occur in IgE binding sites. The 3D-models will facilitate further analysis of the common properties of IgE binding sites of allergenic proteins.

Cloning of IgE from the echidna (Tachyglossus aculeatus) and a comparative analysis of epsilon chains from all three extant mammalian lineages.

In continuation of our evolutionary studies of immunoglobulin (Ig) expression, we present here the cloning of IgE from a monotreme, the short-beaked echidna (Tachyglossus aculeatus). Including echidna IgE, 15 epsilon chain sequences have been isolated and each of the three mammalian lineages (placentals, marsupials and monotremes) is now represented by at least two sequences. Phylogenetic analyses based on all available epsilon chains and a selection of other mammalian Ig isotypes (IgM, IgA and IgG) were generated using three different algorithms. The resulting trees strongly support the Theria hypothesis, which states that the monotreme lineage was the first of the three extant mammalian lineages to appear in evolution. Furthermore, to increase our understanding of IgE we have done a detailed comparative analysis, with focus on primary structure, potential N-glycosylation, charge distribution and conservation of residues in the putative receptor-binding site. The overall structure of IgE, i.e. four constant domains and the positions of putative disulfide-bridge formations, are conserved, as is an N-glycosylation site in the third constant domain. An increased homology was observed in the putative receptor-binding site, which suggests an important function for the IgE/Fc epsilon RI interaction. IgE has been found exclusively in mammals, but it is present in all extant mammalian lineages. This, together with the overall conservation of structure, indicates that IgE appeared as a separate isotype early in mammalian evolution and that structural maintenance may have a selective advantage.

Further characterization of IgE-binding antigens from guinea pig hair as new members of the lipocalin family.

BACKGROUND: Guinea pigs are important sources of inhalant allergens in home and working environments. However, little is known about the molecular characteristics and the relevant epitopes of guinea pig allergens. Recently, several allergens have been identified in hair extract and urine, and the major allergen Cav p 1 (20 kDa) has been characterized. OBJECTIVE: The aim of the present study was to isolate and to characterize a further major allergen from guinea pig hair with 17 kDa. METHODS: Guinea pig hair extract was fractionated using anion exchange chromatography and reverse-phase high performance liquid chromatography. Analyses were carried out by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, 2D-PAGE, immunoblotting, immunoblot inhibition, glycoprotein detection, and N-terminal amino acid sequencing. RESULTS: The nonglycosylated 17 kDa allergen, which was named Cav p 2, was purified to homogeneity. On the basis its 15 N-terminal residues, there was 69% identity with a sequence of Bos d 2, an allergenic protein from cow dander belonging to the lipocalin family. The 2D-immunoblotting analyses of guinea pig hair extract demonstrated that Cav p 2 and Cav p 1, contained several isoforms with pI values ranging from 3.6 to 5.3. The 2D-immunoblot inhibition disclosed cross-reactive IgE epitopes on the allergens Cav p 2 and Cav p 1. Furthermore, Cav p 1 can form both monomers (20 kDa) and dimers (40-42 kDa). CONCLUSION: These studies provide important information on the isoallergen character of two relevant guinea pig allergens Cav p 1 and Cav p 2 as well as on their cross-reactive properties.

IgG reactive to CTL-directed epitopes of self-antigens is either lacking or unbalanced in atopic dermatitis patients.

We previously demonstrated that CTL-directed epitopes derived from non-mutated self-antigens elicit a type-I allergy in the majority of healthy donors (HD) as did the presence of IgE and IgG reactive to these peptides in the sera of the donors. We investigated in this study whether Igs reactive to eight types of CTL-directed peptides were elevated in the sera of 40 patients with atopic dermatitis (AD). Total IgE levels in the sera of AD patients were significantly higher than those of HD, however, no significant differences between the AD patients and the HD were observed in either the serum levels or the positive rates of IgE reactive to seven of the eight peptides. Total IgG levels were not different from each other, however, IgG reactive to the two peptides with no sequence similarity to other species and one peptide that had similarity to DNA helicase II of enterobacteria were not detectable in the sera of the AD patients. Although IgG reactive to the remaining five peptides, which had sequence similarity to other species, were detectable in both the AD patients and the HD, ratios of peptide-specific IgG1/IgG2 were mostly lower in the AD patients than in the HD. These results indicate that IgG reactive to CTL-directed epitopes of self-antigens is either lacking or unbalanced in AD patients. This information may provide new insight into the immune-mechanisms of elevated auto-reactivity of AD patients.

Data mining of sequences and 3D structures of allergenic proteins.

MOTIVATION: Many sequences, and in some cases structures, of proteins that induce an allergic response in atopic individuals have been determined in recent years. This data indicates that allergens, regardless of source, fall into discreet protein families. Similarities in the sequence may explain clinically observed cross-reactivities between different biological triggers. However, previously available allergy databases group allergens according to their biological sources, or observed clinical cross-reactivities, without providing data about the proteins. A computer-aided data mining system is needed to compare the sequential and structural details of known allergens. This information will aid in predicting allergenic cross-responses and eventually in determining possible common characteristics of IgE recognition. RESULTS: The new web-based Structural Database of Allergenic Proteins (SDAP) permits the user to quickly compare the sequence and structure of allergenic proteins. Data from literature sources and previously existing lists of allergens are combined in a MySQL interactive database with a wide selection of bioinformatics applications. SDAP can be used to rapidly determine the relationship between allergens and to screen novel proteins for the presence of IgE or T-cell epitopes they may share with known allergens. Further, our novel similarity search method, based on five dimensional descriptors of amino acid properties, can be used to scan the SDAP entries with a peptide sequence. For example, when a known IgE binding epitope from shrimp tropomyosin was used as a query, the method rapidly identified a similar sequence in known shellfish and insect allergens. This prediction of cross-reactivity between allergens is consistent with clinical observations. AVAILABILITY: SDAP is available on the web at http://fermi.utmb.edu/SDAP/index.html

Immunoglobulin class and subclass concentrations after treatment of childhood leukemia.

With greatly increased survival rates after childhood leukemia during the last 3 decades, the long-term effects of the treatment have become more evident. The disease and its treatment impair the immune system, but the duration of this impairment is unknown. The authors studied the serum concentrations of immunoglobulins and IgG subclasses in 20 Icelandic children cured of leukemia on average 8 years and 3 months after their treatment ended. Although no marked deviations were found in the concentrations of the main immunoglobulin classes IgA, IgM, IgG, and IgE, the IgG subclass levels were below reference values. The patients had on average 0.9 of age standardized reference values of IgG1, 0.5 of IgG2, 0.8 of IgG3, and 0.7 of IgG4. However, none had any autoimmune diseases or a markedly increased tendency for infections. The results indicate that although the immunoglobulin classes regain their normal values within a few years after cessation of treatment, recovery of the IgG subclasses, especially IgG2, is impaired.

Determination of Blomia tropicalis-specific IgE and IgG subclasses in atopic dermatitis patients.

BACKGROUND: To verify the importance of Blomia tropicalis in atopic dermatitis (AD), we determined the cutaneous reactivity and the serum level of B. tropicalis-specific IgE and IgG subclasses in AD patients. METHODS: B. tropicalis-specific IgE and IgG subclasses were determined in AD patients and compared with bronchial asthma (BA) patients and a control group (CG) of nonatopic subjects. Specific IgE was obtained by skin prick test and RAST. B. tropicalis-specific IgG subclasses were determined by ELISA. The data were statistically analyzed by chi-square test (Mantel-Haenszel) and odds ratio (OR). RESULTS: We detected positive skin prick tests in 61.76% of AD and 83.33% of BA patients, and in 12.5% of the CG. RAST was positive in 44.12% of AD and in 61.90% of BA patients, but not in the CG. B. tropicalis-specific IgG1 and IgG2 subclasses showed no significant differences between the three groups. IgG3 subclass positivity was statistically significant in AD patients (41.17%) when compared to BA patients (14.29%) and the CG (16.67%). The determination of B. tropicalis-specific IgG4 was positive in 32.35% of AD patients, 21.43% of BA patients, and 8.33% of the CG. CONCLUSIONS: These results confirm that the storage mite B. tropicalis is an important allergen in AD. It is possible that IgG3 activates the complement in AD patients, releasing vasoactive amines that further amplify the allergic reaction. The positive results of the B. tropicalis-specific IgG4 found in AD and BA were probably due to chronic exposure to this storage mite in the home environment.

Measles virus infection synergizes with IL-4 in IgE class switching.

Increasing evidence suggests that viral infections are associated with the induction and exacerbation of asthma. One characteristic of human asthma is an increase in the levels of circulating IgE. Previous studies have shown that circulating IgE levels are elevated during the early phase of infection with measles virus (MV). We have shown previously that one mechanism by which viral infections can increase IgE levels is via an induction of IgE class switching through the activation of the antiviral protein kinase (dsRNA-activated protein kinase), leading to the activation of multiple NF-kappaB complexes. Therefore, to determine whether infection with MV can also induce IgE class switching, we infected the human Ramos B cell line with the Edmonston strain of MV. Infecting Ramos cells with MV did not result directly in either the activation of dsRNA-activated protein kinase or IgE class switching. However, a synergistic effect on IgE class switching was observed when Ramos cells were infected with MV before IL-4 treatment. Ab cross-linking of the MV receptor, CD46, mimicked the effects of MV infection in synergizing with IL-4 to induce IgE class switching, suggesting that viral hemagglutinin is involved in this synergistic effect. These data provide the first indication of a potential mechanism for MV-induced IgE up-regulation and suggest a model for a viral-induced exacerbation of IgE-mediated disorders such as asthma.

Allergic conjunctivitis and dry eye.

AIMS: Differential diagnosis of allergic conjunctivitis or dry eye is sometimes very difficult to diagnose by symptoms and clinical examination alone, especially in older patients. It was hypothesised that clinically allergic patients who were serum antigen specific IgE negative were candidates for dry eye. METHODS: Sixty patients were studied prospectively who were clinically diagnosed with allergic conjunctivitis by their itchy sensation and papilla formation of conjunctiva. They consisted of 30 serum antigen specific IgE positive and 30 IgE negative patients, with no significant differences in age. Dry eye examination and serum total IgE were performed on these two groups. RESULTS: No significant differences were seen between the two groups with regard to age (p = 0.76) and sex ratio. The antibody negative group had lower Schirmer's test scores (p = 0.002), lower tear clearance (p = 0.0001), lower tear function index (p = 0.0001), and lower serum total IgE (p = 0.04) than the antibody positive group. CONCLUSION: This study suggests that the evaluation of serum antigen specific IgE and tear dynamics are important for the differential diagnosis of patients with allergic conjunctivitis and dry eye. Clinically diagnosed allergic conjunctivitis with negative serum antigen specific and total IgE can be one form of dry eye.

In vitro and in vivo effect of glucocorticoids on IgE and IgG subclass secretion.

Hydrocortisone (HC) as well as its synthetic derivatives have been shown to strongly enhance interleukin-4 (IL-4)-induced in vitro IgE synthesis. To investigate possible effects on IgG subclasses, peripheral blood mononuclear cells (PBMC) were incubated with different glucocorticosteroids in the absence or presence of IL-4. The glucocorticoids alone led to a strongly enhanced secretion of IgG1, IgG2 and IgG3, but not IgG4. The addition of IL-4 induced marked increases in IgG1 and IgG4, no changes in IgG3, but a consistent decrease in IgG2 synthesis. In order to find out whether these profound in vitro effects of corticosteroids are also reflected by changes in antibody serum levels during steroid treatment, 10 healthy volunteers took 25 mg prednisone for 7 consecutive days. We could not observe any significant changes of IgE or IgG subclass serum levels during or after this period. However, cell cultures performed after the glucocorticoid treatment revealed a marked decrease in the ability to produce IgG4 and a significantly lower potential to produce IgE in response to IL-4 alone or IL-4 and HC. We conclude that, although strongly implicated by the in vitro results, glucocorticosteroid treatment does not result in an increased allergy risk.