Bronchial hyper-responsiveness in selective IgA deficiency

Clinical manifestation for immunoglobulin A deficiency: a systematic review and meta-analysis

OBJECTIVES

Immunoglobulin A deficiency (IgAD) is a common disease with an unknown genetic defect, characterized by the decreased or absent IgA with other isotypes normal, normal subclasses, and specific antibodies. Patients with this disorder represent a spectrum of clinical manifestations including infections, autoimmune disorders, malignancy, and allergic diseases. The current study aimed to evaluate their prevalence and categorized them.

METHODS

We searched PubMed, Web of Science, and Scopus databases to find eligible studies from the earliest available date to January 2022 with standard keywords. Pooled estimates of clinical manifestations prevalence and the corresponding 95% confidence intervals were calculated using random-effects models.

RESULTS

The most prevalent clinical manifestations belonged to infection (64.8%) followed by allergic diseases (26.16%) and autoimmunity (22.0%), respectively. In selective IgA deficiency patients as the largest group of IgAD in current study, celiac disease (6.57%), Inflammatory bowel disease (4.01%), and rheumatoid arthritis (3.80%) were the most prevalent autoimmunity. Meanwhile, the most frequent infection was respiratory tract infection, fungal infection, and gastrointestinal infection at 50.74%, 18.48%, and 15.79%, respectively. In addition, the pooled prevalence of asthma, allergic rhinitis, and allergic conjunctivitis were 19.06%, 15.46%, and 11.68%, respectively which were reported as the most widespread allergic diseases.

CONCLUSIONS

Our results showed that apart from undiagnosed IgAD patients, IgAD patients represent a wide range of clinical manifestations. Infection, allergy, and autoimmunity are the most common clinical manifestations. The concurrent presence of IgA and IgG subtypes deficiency could be associated with increased susceptibility to infection. Considering the probability of developing new clinical complications during follow-up, periodic assessments of IgAD patients should be inspected.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

The Allergic Phenotype of Children and Adolescents with Selective IgA Deficiency: A Longitudinal Monocentric Study

Background: Selective IgA deficiency (SIgAD) is the most common inborn error of immunity. The exact prevalence and pathogenesis of allergy in SIgAD have not yet been defined. We aimed to describe the prevalence and the characteristics of allergy in pediatric SIgAD subjects, evaluate the association between allergy and other comorbidities, and define the immune phenotype of allergic and non-allergic patients. Methods: Clinical and immunological data from 67 SIgAD patients were collected over a 13-year period at a single center. Patients’ characteristics were analyzed according to the presence of allergy. Results: Allergy was diagnosed in 34% of SIgAD patients, with a median age at allergy diagnosis of 8 years. Allergy was the second-most-common clinical manifestation, following recurrent respiratory infections. Among the allergic group, 74% had rhinitis, 30% asthma, 30% atopic dermatitis, and 22% food allergy; one out of three had more than one allergic manifestation. SIgAD patients showed more frequent transitory lymphopenia and a lower count of CD19+ at diagnosis than at last FU. However, compared to non-allergic subjects, allergic patients did not differ in their immune phenotype, number and severity of infections, or increased autoimmunity. Conclusions: In our longitudinal study, compared to non-allergic SIgAD patients, those with allergies did not present a more severe immune defect or complex clinical phenotype. However, evaluation and early identification of allergy in the context of SIgAD assessment, both at diagnosis and during FU, and definition of a proper management are important to prevent complications and improve the patient’s quality of life.

Identification of ANXA2 on epithelial cells as a new receptor for secretory IgA using immunoprecipitation and mass spectrometry

Secretory immunoglobulin A plays an important role in the protection against exogenous pathogens and antigens, but it has also been reported to have pathogenic potential. We previously found that secretory immunoglobulin A accumulated in the peripheral lungs during idiopathic pulmonary fibrosis and that transferrin receptor/CD71 was partially involved in secretory immunoglobulin A-induced inflammatory cytokine production in A549 cells. This study aimed to identify the receptor responsible for the induction of cytokine production by secretory immunoglobulin A-stimulated airway epithelial cells. To this end, immunoprecipitation followed by time-of-flight mass spectrometry and peptide mass fingerprinting were performed and Annexin A2 was detected as a novel receptor for secretory immunoglobulin A. Enzyme-linked immunosorbent assay demonstrated binding of secretory immunoglobulin A to Annexin A2, and flow cytometry showed robust expression of Annexin A2 on the surface of BEAS-2B cells, A549 cells, and normal human bronchial/tracheal epithelial cells. Experiments in A549 cells using Annexin A2 small interfering RNA and neutralizing antibodies suggested that Annexin A2 was partially involved in the production of interleukin-8/CXCL8 and C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 induced by secretory immunoglobulin A. Immunohistochemistry using lung sections revealed clear expression of Annexin A2 on airway epithelial cells, although the staining remained equivalent in idiopathic pulmonary fibrosis, asthma, and healthy control lungs. In conclusion, we identified that Annexin A2 expressed in airway epithelial cells is a novel receptor for secretory immunoglobulin A, which is involved in cytokine synthesis.

Selective IgA Deficiency and Allergy: A Fresh Look to an Old Story

Selective IgA deficiency (SIgAD) is the most common human primary immune deficiency (PID). It is classified as a humoral PID characterized by isolated deficiency of IgA (less than 7 mg/dL but normal serum IgG and IgM) in subjects greater than 4 years of age. Intrinsic defects in the maturation of B cells and a perturbation of Th cells and/or cytokine signals have been hypothesized to contribute to SIgAD pathogenesis. The genetic basis of IgA deficiency remains to be clarified. Patients with SIgAD can be either asymptomatic or symptomatic with clinical manifestations including allergy, autoimmunity and recurrent infections mainly of the respiratory and gastrointestinal tract. Studies analyzing allergy on SIgAD patients showed prevalence up to 84%, supporting in most cases the relationship between sIgAD and allergic disease. However, the prevalence of allergic disorders may be influenced by various factors. Thus, the question of whether allergy is more common in SIgAD patients compared to healthy subjects remains to be defined. Different hypotheses support an increased susceptibility to allergy in subjects with SIgAD. Recurrent infections due to loss of secretory IgA might have a role in the pathogenesis of allergy, and vice versa. Perturbation of microbiota also plays a role. The aim of this review is to examine the association between SIgAD and atopic disease and to update readers on advances over time at this important interface between allergy and SIgAD.

The Epidemiology and Clinical Presentations of Atopic Diseases in Selective IgA Deficiency

Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency disease (PID), with an estimated occurrence from about 1:3000 to even 1:150, depending on population. sIgAD is diagnosed in adults and children after the 4th year of age, with immunoglobulin A level below 0.07 g/L and normal levels of IgM and IgG. Usually, the disease remains undiagnosed throughout the patient's life, due to its frequent asymptomatic course. If symptomatic, sIgAD is connected to more frequent viral and bacterial infections of upper respiratory, urinary, and gastrointestinal tracts, as well as autoimmune and allergic diseases. Interestingly, it may also be associated with other PIDs, such as IgG subclasses deficiency or specific antibodies deficiency. Rarely sIgAD can evolve to common variable immunodeficiency disease (CVID). It should also be remembered that IgA deficiency may occur in the course of other conditions or result from their treatment. It is hypothesized that allergic diseases (e.g., eczema, rhinitis, asthma) are more common in patients diagnosed with this particular PID. Selective IgA deficiency, although usually mildly symptomatic, can be difficult for clinicians. The aim of the study is to summarize the connection between selective IgA deficiency and atopic diseases.

Evaluation of pulmonary findings in patients with humoral immunodeficiency

Aim:

To determine the frequency of sinopulmonary infections, detect changes in the respiratory system, and measure functional capacity of the lungs in our patients with humoral immunodeficiency.

Material and Methods:

Fifty-six patients with humoral immunodeficiency were enrolled in this study. The clinical, laboratory, and radiologic data, and pulmonary function tests of the subjects were evaluated from their file records, retrospectively.

Results:

The distribution of our patients was as follows: 25 patients had common variable immune deficiency, three patients had X-linked agammaglobulinemia, five patients had hyper immunoglobulin M syndrome, 19 patients had deficiency of immunoglobulin G subset, and four patients had selective immunoglobulin A deficiency. The most common symptom of the patients was chronic cough (n=47, 83.9%). The most common pathologies on high-resolution computed tomography of the chest were atelectasis and bronchiectasis (27.7%). The most common pathology in pulmonary function tests was the presence of moderate obstructive patterns along with restrictive patterns (n=6,12.5%). The FEV 1, FVC, and FEF 25–75 values were significantly lower in patients with common variable immunodeficiency compared with the patients who had IgG subset deficiencies (p=0.001, p=0.01, p=0.01). Among the patients who were treated with intravenous immunoglobulin, the age at the diagnosis of immunodeficiency was higher in patients with bronchiectasis (14.2±8.4 years) compared with those without bronchiectasis (10.1±11.4 years) (p=0.04).

Conclusion:

Clinical findings are not sufficient to monitor the structural and functional changes in the respiratory system, and patients should be evaluated using high-resolution computed tomography of the chest and pulmonary function tests.

More Than Just a Barrier: The Immune Functions of the Airway Epithelium in Asthma Pathogenesis

Allergic bronchial asthma is a chronic disease of the airways that is characterized by symptoms like respiratory distress, chest tightness, wheezing, productive cough, and acute episodes of broncho-obstruction. This symptom-complex arises on the basis of chronic allergic inflammation of the airway wall. Consequently, the airway epithelium is central to the pathogenesis of this disease, because its multiple abilities directly have an impact on the inflammatory response and thus the formation of the disease. In turn, its structure and functions are markedly impaired by the inflammation. Hence, the airway epithelium represents a sealed, self-cleaning barrier, that prohibits penetration of inhaled allergens, pathogens, and other noxious agents into the body. This barrier is covered with mucus that further contains antimicrobial peptides and antibodies that are either produced or specifically transported by the airway epithelium in order to trap these particles and to remove them from the body by a process called mucociliary clearance. Once this first line of defense of the lung is overcome, airway epithelial cells are the first cells to get in contact with pathogens, to be damaged or infected. Therefore, these cells release a plethora of chemokines and cytokines that not only induce an acute inflammatory reaction but also have an impact on the alignment of the following immune reaction. In case of asthma, all these functions are impaired by the already existing allergic immune response that per se weakens the barrier integrity and self-cleaning abilities of the airway epithelium making it more vulnerable to penetration of allergens as well as of infection by bacteria and viruses. Recent studies indicate that the history of allergy- and pathogen-derived insults can leave some kind of memory in these cells that can be described as imprinting or trained immunity. Thus, the airway epithelium is in the center of processes that lead to formation, progression and acute exacerbation of asthma.

Secretory IgA accumulated in the airspaces of idiopathic pulmonary fibrosis and promoted VEGF, TGF-β and IL-8 production by A549 cells

Secretory IgA (SIgA) is a well-known mucosal-surface molecule in first-line defense against extrinsic pathogens and antigens. Its immunomodulatory and pathological roles have also been emphasized, but it is unclear whether it plays a pathological role in lung diseases. In the present study, we aimed to determine the distribution of IgA in idiopathic pulmonary fibrosis (IPF) lungs and whether IgA affects the functions of airway epithelial cells. We performed immunohistochemical analysis of lung sections from patients with IPF and found that mucus accumulated in the airspaces adjacent to the hyperplastic epithelia contained abundant SIgA. This was not true in the lungs of non-IPF subjects. An in-vitro assay revealed that SIgA bound to the surface of A549 cells and significantly promoted production of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β and interleukin (IL)-8, important cytokines in the pathogenesis of IPF. Among the known receptors for IgA, A549 cells expressed high levels of transferrin receptor (TfR)/CD71. Transfection experiments with siRNA targeted against TfR/CD71 followed by stimulation with SIgA suggested that TfR/CD71 may be at least partially involved in the SIgA-induced cytokine production by A549 cells. These phenomena were specific for SIgA, distinct from IgG. SIgA may modulate the progression of IPF by enhancing synthesis of VEGF, TGF-β and IL-8.

IgA and FcαRI: Pathological Roles and Therapeutic Opportunities

Immunoglobulin A (IgA) is the most abundant antibody class present at mucosal surfaces. The production of IgA exceeds the production of all other antibodies combined, supporting its prominent role in host-pathogen defense. IgA closely interacts with the intestinal microbiota to enhance its diversity, and IgA has a passive protective role via immune exclusion. Additionally, inhibitory ITAMi signaling via the IgA Fc receptor (FcαRI; CD89) by monomeric IgA may play a role in maintaining homeostatic conditions. By contrast, IgA immune complexes (e.g., opsonized pathogens) potently activate immune cells via cross-linking FcαRI, thereby inducing pro-inflammatory responses resulting in elimination of pathogens. The importance of IgA in removal of pathogens is emphasized by the fact that several pathogens developed mechanisms to break down IgA or evade FcαRI-mediated activation of immune cells. Augmented or aberrant presence of IgA immune complexes can result in excessive neutrophil activation, potentially leading to severe tissue damage in multiple inflammatory, or autoimmune diseases. Influencing IgA or FcαRI-mediated functions therefore provides several therapeutic possibilities. On the one hand (passive) IgA vaccination strategies can be developed for protection against infections. Furthermore, IgA monoclonal antibodies that are directed against tumor antigens may be effective as cancer treatment. On the other hand, induction of ITAMi signaling via FcαRI may reduce allergy or inflammation, whereas blocking FcαRI with monoclonal antibodies, or peptides may resolve IgA-induced tissue damage. In this review both (patho)physiological roles as well as therapeutic possibilities of the IgA-FcαRI axis are addressed.

Pulmonary Manifestations of Predominantly Antibody Deficiencies

Predominantly antibody deficiencies (PADs) are the most frequent forms of primary immunodeficiency diseases (PIDs). Commonly accompanied with complications involving several body systems, immunoglobulin substitution therapy along with prophylactic antibiotics remained the cornerstone of treatment for PADs and related complications. Patients with respiratory complications should be prescribed an appropriate therapy as soon as possible and have to be adhering to more and longer medical therapies. Recent studies identified a gap for screening protocols to monitor respiratory manifestations in patients with PADs. In the present chapter, the pulmonary manifestations of different PADs for each have been discussed. The chapter is mainly focused on X-linked agammaglobulinemia, common variable immunodeficiency, activated PI3K-δ syndrome, LRBA deficiency, CD19 complex deficiencies, CD20 deficiency, other monogenic defects associated with hypogammaglobulinemia, immunoglobulin class switch recombination deficiencies affecting B-cells, transient hypogammaglobulinemia of infancy, and selective IgA deficiency.

Relationship between serum IgA level and allergy/asthma

BACKGROUND/AIMS

Mucosal immunoglobulin A (IgA) may prevent the entrance of allergens. This study examined the relationship between serum IgA levels (within the normal range) and sensitization to house dust mites (HDM) or airway hyper-responsiveness (AHR).

METHODS

The clinical records of 1,136 adult patients with suspected asthma, for whom test data for serum IgA level and methacholine-AHR were available, were reviewed retrospectively. The AHR/allergy indices were compared among patient groups with low (<140 mg/dL, group I), intermediate (140 to 280 mg/dL, group II), or high (≥280 mg/dL, group III) IgA levels in serum.

RESULTS

The HDM skin sensitization rate progressively decreased from 30.0% in group I (n = 139) to 26.8% and 18.5% in groups II (n = 684) and III (n = 313), respectively (p = 0.003). Although both the HDM sensitization degree and the IgA level were significantly related to age, the adjusted odds ratio (OR) of association of a high IgA level (≥ 280 mg/dL) with HDM sensitization was significant (0.617; 95% confidence interval [CI], 0.415 to 0.916; p = 0.017). Among younger subjects (≤ 45 years of age) with AHR, the prevalence of moderate/severe AHR progressively decreased (70.6%, 52.3%, and 47.1% in groups I, II, and III [n = 34, 149, and 51]), respectively (p = 0.045). The IgA < 140 mg/dL was a significant risk factor for moderate/severe AHR (OR, 2.306; 95% CI, 1.049 to 5.071; p = 0.038).

CONCLUSIONS

Sensitization to HDM and methacholine-AHR were significantly associated with serum IgA levels in suspected asthmatics, even when those levels were normal.

Bronchial hyperreactivity in children with antibody deficiencies

BACKGROUND

Antibody deficiency comprises a heterogeneous group of disorders characterised by the body's inability to mount an effective antibody response to pathogens. Although it has been reported that asthma and allergic disease are frequent in antibody deficiencies, there are no data that evaluate and compare bronchial hyperreactivity (BHR) in all groups of antibody deficiencies. In this study, we aimed to evaluate and compare the frequency of BHR in patients with different antibody deficiencies.

METHODS

The study was carried out on 113 patients between ages 5 and 18 diagnosed with antibody deficiencies. The patients and their families were questioned on their history of asthma and allergic diseases. Allergic skin prick tests and non-specific bronchial provocation test with methacholine was done for all patients. Complete blood count and serum total IgE levels were measured.

RESULTS

The mean age of the patients was 10.8 ± 3.8 years and 66.4% were male. Within the study group 41.6% of the patients had selective IgA deficiency, 24.8% had IgG subclass deficiency, 14.2% had partial IgA deficiency, 10.6% had common variable immunodeficiency, 6.2% had transient hypogammaglobulinaemia and 2.7% X-linked agammaglobulinaemia. In total group, 42.5% had bronchial hyperreactivity with methacholine challenge test. BHR was more significant in both patients with selective IgA deficiency and partial IgA deficiency compared to those with IgG subclass deficiency (P=0.041 and P=0.038, respectively).

CONCLUSION

BHR was high in antibody deficiencies, especially selective IgA deficiency compared to IgG subclass deficiency.

Asthma and risk of selective IgA deficiency or common variable immunodeficiency: a population-based case-control study

OBJECTIVE

To determine the association between a history of asthma and a diagnosis of selective IgA deficiency (sIgAD)/common variable immunodeficiency (CVID).

PATIENTS AND METHODS

This population-based case-control study included residents of Olmsted County, Minnesota, who met the Pan-American Group for Immunodeficiency/European Society for Immunodeficiencies diagnostic criteria for sIgAD/CVID between January 1, 1964, through December 31, 2008. Each case had 4 age- and sex-matched controls (2 from the community and 2 from a list of individuals who had undergone an immune work-up). We ascertained asthma status by applying predetermined criteria for asthma.

RESULTS

We identified 39 cases: 26 (66.7%) had sIgAD and 13 (33.3%) had CVID. Of the 39 cases, 51.3% were men (n=20) and 97.1% were white (33 of 34 patients). The mean age at the index date (the time when criteria were met) of sIgAD/CVID was 34.2 years. Of the 39 cases, 9 (23.1%) had a history of asthma before the index date of sIgAD/CVID; of the 156 controls, 16 (10.3%) had a history of asthma before the index date (odds ratio, 2.77; 95% CI, 1.09-7.06; P=.03). A history of asthma (before or after the index date of sIgAD/CVID) was more prevalent in sIgAD/CVID cases (30.8%; n=12) than in matched controls (11.5%; n=18) (odds ratio, 3.57; 95% CI, 1.50-8.51; P=.01).

CONCLUSION

Asthmatic patients are more likely to have a diagnosis of sIgAD/CVID than nonasthmatic individuals. This association may potentially account for the increased risks of bacterial infections in some individuals with asthma.

An overlapping syndrome of allergy and immune deficiency in children

Recurrent airway inflammations in children are an important clinical problem in pediatric practice. An essential challenge is differentiation between allergic background and immune deficiency, which is a difficult task taking into consideration individual predisposition to atopy, immune system maturation in the early childhood, as well as exposition to environmental allergens and microbial antigens. In this paper relationship between selected elements of innate and adaptive immunity, such as pattern-recognition receptors, complement components, dendritic cells, as well as immunoglobulins, and regulatory T lymph cells has been discussed. Particular attention has been paid to these mechanisms of the immune response which, depending on settings and timing of activation, predispose to allergy or contribute to tolerogenic phenotype. In the context of multifactorial conditioning of the innate and adaptive immunity governing the ultimate response and associations between allergy and immune deficiencies, these phenomena should be considered as pathogenetically not precluding, but as an overlapping syndrome.

Serum immunoglobulin levels as a predictive factor for a better outcome of non-atopic childhood asthma

Childhood asthma is a heterogeneous condition with different phenotypes. Hereby, we aimed to study impact of serum immunoglobulin levels on clinical phenotypes and outcome of asthma. Seventy-eight children (M: 26, F: 52) aged less than 10 yrs (mean = 8.56 ± 3.23 yrs) and diagnosed as mild-moderate persistent asthma, followed up for at least 1 yr were included into the study. Asthmatic children were divided into two groups based on serum immunoglobulin levels at admission and were evaluated with respect to demographic data, allergic sensitization, symptom scores, medication usage, pulmonary functions, and non-specific bronchial hyper-reactivity. The age at onset of symptoms (40.88 ± 32.02 vs. 23.04 ± 26.97 months) was significantly younger in children with hypogammaglobulinemia (n = 28) compared to normogammaglobulinemia group (n = 50) (p = 0.016). Mean follow-up duration was 3.8 ± 2.1 yrs. Atopic sensitization rate was higher in those with normal immunoglobulin levels (81.2% vs. 17.9%), (p < 0.0001). Normal serum immunoglobulin levels were associated with atopic asthma (OR, 4.5; 95% confidence interval (CI): 2.0-10.1). For the prediction of atopic asthma, having normal immunoglobulin levels yielded predictive values of: sensitivity = 88.6%, specificity = 71.8%, positive predictive value = 81.1%, negative predictive value = 82.1%. Furthermore, percentages of atopic dermatitis and allergic conjunctivitis, elevated serum total IgE levels, eosinophilia, and bronchial hyper-reactivity were more common in normogammaglobulinemia with asthma group (p = 0.040, p = 0.003, p = 0.024, p = 0.030, p = 0.040, respectively). Although marked reductions in asthma scores and inhaled corticosteroid usage were observed in both groups over time, the rate of decline was significantly higher and earlier in hypogammaglobulinemia group (p = 0.0001, p = 0.004, respectively). In conclusion, asthmatic children with hypogammaglobulinemia presented at an earlier age, with lower rates of atopy, and earlier clinical improvement accompanied with earlier discontinuation of inhaled corticosteroids than children with normal immunoglobulin levels. Our data demonstrated that in children currently named as early-onset non-atopic asthma, hypogammaglobulinemia might be accompanying, providing evidence for a different phenotype of childhood asthma.

Outcome of hypogammaglobulinemia in children: immunoglobulin levels as predictors

We evaluated 131 children (M=88, F=43) with hypogammaglobulinemia. Data was analyzed mainly for delineating predictor factors for outcome. The distance from the lower limit of normal (-2SD) for any single measurement of immunoglobulins (Ig) was calculated and transformed into Ig scores. Mean age and duration of follow-up were 5.06 ± 4.05 and 3.7 ± 3.03 years, respectively. The diagnoses were: 22 CVID, 16 IgA deficiency, 33 transient hypogammaglobulinemia of childhood (THC), 3 selective IgM deficiency and 57 unclassified hypogammaglobulinemia (UCH). Low IgA scores (<-0.124) at presentation were indicative of subsequent development of IgA deficiency or CVID, whereas low IgM score (<-0.038) pointed towards more severe and persistent phenotypes. Combination of low IgM score between 2 and 5 years, impaired antibody response and low B cell counts enabled us to predict persistence of hypogammaglobulinemia beyond 5 years (specificity=90.5% and PPV=94.9%) and chronic lung disease (sensitivity=90.4% and specificity=68.3%). The set of criteria including low IgM scores, impaired antibody response and low B cell counts provided a high predictive value in detecting those with persistent hypogammaglobulinemia.

Transient hypogammaglobulinemia and unclassified hypogammaglobulinemia: 'similarities and differences'

Transient hypogammaglobulinemia of infancy (THI) is characterized by recurrent infections and one or more reduced serum immunoglobulin (Ig) levels. Usually, this clinical picture resolves spontaneously by 3 yr of age. However, hypogammaglobulinemia persists until adolescence in some patients. In recent years, those patients have been classified as undefined/unclassified hypogammaglobulinemia (UCH). We aimed to evaluate the clinical and immunologic features of patients with THI and UCH considering age of recovery and to assess relationships between hypogammaglobulinemia, infections, and allergic manifestations. We reviewed the medical records of children followed with a diagnosis of hypogammaglobulinemia from 2001 to 2007. Patients with decreased levels (<2 s.d.) of one or more major Ig isotypes (IgG, IgA, IgM) with normal antibody responses and lymphocyte subpopulations were included (n = 374). Those patients whose Igs normalized during the follow-up period were classified as THI and the others as UCH. The THI group consisted of 71 patients (27 females, 44 males) with a mean recovery age of 68.87 +/- 36.5 months. About 95% of patients with THI recovered before 10 yr of age. The UCH group consisted of 303 patients (105 females, 198 males) with a mean age at diagnosis of 52 +/- 42 months. The most common presenting manifestations in the THI and UCH groups were upper respiratory tract infections (URTIs), lower respiratory tract infections, and asthma (42%, 50%, and 52% in the THI group vs. 39%, 53%, and 55% in the UCH group, respectively). In the THI group, the prevalence of atopic disease was related to age and found to be increased markedly after 44 months. In all patients, the prevalence of asthma was independently and positively associated with family history of atopy and age, whereas it was negatively associated with recurrent URTIs. Patients with THI and UCH have similar clinical and immunologic features. The normalization of Igs may be delayed in a majority of the patients with hypogammaglobulinemia. This observation may be a contribution to the classical definition and diagnostic criteria for THI.

Allergic asthma in patients with common variable immunodeficiency

BACKGROUND

Many patients with common variable immunodeficiency (CVID) have a clinical history suggestive of allergic respiratory disease. However, in such individuals, the prevalence of asthma and the role of atopy have not been well established. The objective of this study was to evaluate pulmonary function and identify asthma in patients with CVID. We also investigated the role of IgE as a trigger of asthma in these patients.

METHODS

Sixty-two patients diagnosed with CVID underwent spirometry, as well as skin prick testing and in vitro determination of serum-specific IgE levels for aeroallergens, together with bronchial provocation with histamine and allergen.

RESULTS

The most common alteration identified through spirometry was obstructive lung disease, which was observed in 29 (47.5%) of the 62 patients evaluated. Eighteen (29.0%) of the 62 patients had a clinical history suggestive of allergic asthma. By the end of the study, asthma had been diagnosed in nine (14.5%) patients and atopy had been identified in six (9.7%). In addition, allergic asthma had been diagnosed in four patients (6.5% of the sample as a whole; 22.2% of the 18 patients with a clinical history suggestive of the diagnosis).

CONCLUSION

In this study, CVID patients testing negative for specific IgE antibodies and suspected of having allergic asthma presented a positive response to bronchial provocation tests with allergens. To our knowledge, this is the first such study. When CVID patients with a history suggestive of allergic asthma test negative on traditional tests, additional tests designed to identify allergic asthma might be conducted.

High intestinal IgA associates with reduced risk of IgE-associated allergic diseases

Development of oral tolerance and its stimulation by probiotics are still incomprehensible. Microbial stimulation of the gut may induce a subtle inflammation and induce secretion of mucosal IgA, which participates in antigen elimination. In a cohort of allergy-prone infants receiving probiotics and prebiotics or placebo we studied intestinal IgA and inflammation in the development of eczema, food allergy, asthma, and rhinitis (allergic diseases). We performed a nested unmatched case-control study of 237 infants participating in a randomized double-blind placebo-controlled allergy-prevention trial using a combination of four probiotic strains pre-natally and during 6 months form birth. We measured faecal IgA, alpha1-antitrypsin (alpha1-AT), tumour necrosis factor-alpha (TNF-alpha), and calprotectin at the age of 3 and 6 months. By age 2 yr, 124 infants had developed allergic disease or IgE-sensitization (cases) and 113 had not (controls). In infants with high faecal IgA concentration at the age of 6 months, the risk of having any allergic disease before the age of 2 yr tended to reduce [odds ratio (OR: 0.52)] and the risk for any IgE-associated (atopic) disease reduced significantly (OR: 0.49). High faecal calprotectin at the age of 6 months associated also with lower risk for IgE-associated diseases up to age 2 yr (OR: 0.49). All faecal inflammation markers (alpha1-AT, TNF-alpha, and calprotectin) correlated positively with faecal IgA (p < 0.001). Probiotics tended to augment faecal IgA (p = 0.085) and significantly increased faecal alpha1-AT (p = 0.001). High intestinal IgA in early life associates with minimal intestinal inflammation and indicates reduced risk for IgE-associated allergic diseases.

Difficult-to-control asthma management through the use of a specific protocol

The present study is a critical review of difficult-to-control asthma, highlighting the characteristics and severity of the disease. It also presents a protocol for the management of patients with this asthma phenotype. The protocol, which was based on relevant studies in the literature, is described and analyzed.