Anna Zawadzka-Krajewska

Frequency and Activation of CD4+CD25high FoxP3+ Regulatory T Cells in Peripheral Blood from Children with Atopic Allergy

Background: Atopic allergy is among the immune tolerance-related disorders resulting from a failure of the regulatory network. Regulatory T cells (Tregs) play a leading role in the development of homeostasis in the immune system. The aim of this study was to determine the role of Tregs in the pathogenesis of atopic diseases in children by exploring the relationship between Treg frequency, activation markers and the clinical manifestations of the disease. Methods: Twenty allergic and 50 healthy children were enrolled to the study. Peripheral blood mononuclear cells were stained with monoclonal antibodies (anti-CD25-CD4-CD127-FoxP3-CD69-CD71) and evaluated using flow cytometry. Tregs were identified as CD4+CD25+/highFoxP3+CD127- T cells. Results: The percentage of Tregs in allergic patients (2.3%) was significantly decreased in comparison to healthy controls (4.6%, p = 0.003). The frequency of Tregs in patients with symptoms of atopic dermatitis and/or food allergy (1.7%) was significantly lower than in patients without these symptoms (2.9%, p = 0.04). A significant correlation between the percentage of Tregs and the sIgE serum concentration was observed (p = 0.037). Relative fluorescence intensities of FoxP3 expression in allergic patients were higher than in healthy controls (p = 0.00004). The frequency of CD4+CD25highCD127-CD71+ cells did not differ between the groups. Conclusions: Tregs display substantial deficiencies in atopic children, especially in children with multiorgan involvement, compared to patients with single organ manifestations. Additionally, there is an association between Tregs and the sIgE serum concentration. Better identification and characterization of Tregs in allergy is needed as they limit responses to foreign antigens, thereby minimizing T cell-mediated immunopathology in allergic diseases.

Prolonged Treatment with Inhaled Corticosteroids does not Normalize High Activity of Matrix Metalloproteinase-9 in Exhaled Breath Condensates of Children with Asthma.

The airway remodeling in asthma is associated with increased amount of matrix metalloproteinase (MMP)-9. High levels of MMP-9 were found in mucosal biopsies, sputum and in exhaled breath condensates (EBC) of asthma patients. However, there are no data concerning real in vivo activity. Inhaled corticosteroids are effective in asthma control, but it is unclear, whether they only attenuate inflammation, or also protect against progressive remodeling of respiratory tract. Therefore, the aim of the study was to assess the amount and activity of MMP-9 in context of pro-inflammatory cytokines (IL-6, IL-8 and tumor necrosis factor, TNF), measured in EBC of asthma-suffering children, treated with inhaled steroids. The study involved 27 children with asthma, continuously treated with inhaled fluticasone propionate, and 22 healthy controls. In addition to routine clinical screening, the selected cytokines in EBC were analyzed using Ultrasensitive ELISA, whereas activity of MMP-9 was assessed using a novel immunozymography method. Despite chronic treatment with inhaled steroids mean MMP-9/EBC activity in asthma group was significantly higher than in healthy controls. Moreover, high MMP-9/EBC in asthma-suffering children significantly correlated with IgE serum levels. The IL-6 and IL-8 concentration was below the detection limit in all EBC samples. TNF/EBC levels were similar in both, asthma and healthy children. We hypothesize that MMP-9 hyperactivity in asthma may be closely related to high IgE serum levels. Our results suggest that inhaled steroids may be ineffective to prevent asthma-associated airway remodeling. Finally, we emphasize the necessity of further research focused on MMP-9 inhibition in asthma treatment.

Th1, Th2, Th17, and Regulatory Cytokines in Children with Different Clinical Forms of Allergy

In addition to Th2 cells, other T cell subsets, like Th1, Th17, and regulatory T cells are also involved in the pathogenesis of allergic rhinitis, food allergy, and other allergic diseases. The aim of the study was to evaluate a wide profile of cytokines in the plasma from children with pollen/dust and cow milk allergy with the use of a multiplex Cytometric Bead Array (CBA) test. Twenty children with allergy: 11 with pollen/dust and 9 with cow milk allergy were enrolled into the study. For the analysis of INFγ, IL-2, IL-4, IL-6, IL-10, IL-17A, and TNFα levels, a flow cytometric test was used. TGFβ concentration was measured using an ELISA test. Concentrations of almost all of the detected cytokines in the patients plasma were below 1 pg/ml, with no significant difference between the groups examined. The level of IL-17A was higher in pollen/dust allergy group (median 12.73 pg/ml; 25th percentile-Q1/75th percentile-Q3; 9.28/15.83) in comparison to cow milk allergy group (median 7.86 pg/ml - Q1/Q3; 7.86/14.37). Children with cow milk allergy had a slightly higher concentration of TGFβ than children with pollen/dust allergy (median 28.7 ng/ml - Q1/Q3; 19.77/33.00 vs. 17.84 ng/ml - Q1/Q3; 11.21/23.75, respectively); the difference did not reach statistical significance. We conclude that plasma concentration of Th1, Th2, and Th17 regulatory cytokines are relatively low in allergic children. The CBA test, which could be useful in pediatric practice as it requires a relatively small plasma sample volume, is not sensitive enough to measure low cytokine levels, since its detection limit and the standard curve are not appropriate for the concentrations of these mediators expected in clinical samples.

FoxP3 Tregs Response to Sublingual Allergen Specific Immunotherapy in Children Depends on the Manifestation of Allergy.

Over the last decades allergic diseases has become a major health problem worldwide. The only specific treatment to date is allergen specific immunotherapy (ASIT). Although it was shown that ASIT generates allergen-tolerant T cells, detailed mechanism underlying its activity is still unclear and there is no reliable method to monitor its effectiveness. The aim of our study was to evaluate ASIT influence on the frequency of forkhead box P3 (FoxP3) Tregs in allergic children with various clinical manifestations. The relative number of FoxP3 Tregs in 32 blood samples from allergic children at baseline and/or after 1 year of ASIT was assessed by flow cytometry. In the entire studied group, the percentage of FoxP3 Tregs did not increase 1 year after ASIT. Nevertheless, the percentage of FoxP3 Tregs after ASIT significantly increased in children with respiratory allergy (conjunctivitis, asthma, and rhinitis) coexisting with nonrespiratory manifestations (food allergy and/or atopic dermatitis), whereas, in patients with respiratory allergy only, the percentage of FoxP3 Tregs decreased. To the best of our knowledge, this is the first report showing various differential FoxP3 Tregs response to ASIT in allergic children. FoxP3 Tregs number could be useful in treatment monitoring. Further studies are warranted to confirm these observations.

Influence of Sublingual Immunotherapy on the Expression of Mac-1 Integrin in Neutrophils from Asthmatic Children

Asthma can be effectively treated with sublingual immunotherapy. The influence of -sublingual immunotherapy on the function of granulocytes in asthmatic patients is largely unknown. Mac-1 integrin is a transmembrane protein containing α (CD11b) and β (CD18) chains. High expression of the complex is found on the surface of neutrophils, NK cells, and macrophages. CD11b/CD18 may bind to CD23, ICAM-1, ICAM-2, and ICAM-4. It plays a crucial role in diapedesis of neutrophils. The aim of the present study was to assess Mac-1 expression on neutrophils from asthmatic children before and after sublingual immunotherapy. Twenty five children aged of 8.1 ± 3.1 suffering from atopic asthma and allergic rhinitis, shortlisted for specific immunotherapy, served as the study group. Fifteen healthy individuals, aged 9.8 ± 3.4, served as a control group. The assessment of CD11b and CD18 expression on cells from peripheral blood was performed with a flow cytometer. The tests were performed before and after 12 months of sublingual immunotherapy. In the asthmatic children, 98.08 (90.79-99.12)% of Mac-1 positive neutrophils were detected. The group was divided into two subgroups: of more than 98% and less than 95% of neutrophils with CD11b/CD18 expression in the sample. After immunotherapy, the percentage of Mac-1 positive granulocytes increased to 99.60 (99.29-99.68)%, p = 0.01. In the control group, 90.56 (87.08-88.86)% granulocytes were Mac-1 positive, p = 0.002. We conclude that sublingual immunotherapy strongly influences the function of the immunological system, including Mac-1 expression on neutrophils.

25-Hydroxyvitamin D, biomarkers of eosinophilic inflammation, and airway remodeling in children with newly diagnosed untreated asthma.

BACKGROUND Low 25-hydroxyvitamin D (25[OH]D) and asthma development may be related to airway remodeling and eosinophilia. Periostin is proposed as a key molecule that links remodeling and eosinophilic inflammation. OBJECTIVE We evaluated the association of 25(OH)D concentration with periostin, peripheral blood eosinophil counts, and immunoglobulin E (IgE) in children with newly diagnosed asthma. METHODS The study included 150 children: 110 with atopic asthma and 40 constituted a reference group. Fasting blood was collected for cell counts and serum for measurements of 25(OH)D, periostin, IgE, and C-reactive protein (CRP) concentrations. RESULTS Significantly lower 25(OH)D, elevated IgE concentrations, and eosinophil counts were found in children with asthma compared with the reference group (p = 0.0001). A lower forced expiratory volume in the first second of expiration percentage predicted value was associated with a lower 25(OH)D value in children with asthma. The bronchodilator reversibility was inversely related to serum 25(OH)D concentrations (R = -0.45, p = 0.029). The children with asthma and with a 25(OH)D deficient concentration (≤20 ng/mL) had higher concentrations of periostin (p = 0.035) and CRP (p = 0.01) than those with a sufficient 25(OH)D concentration (≥30 ng/L). Additional analysis revealed statistically significant differences (p = 0.013) when comparing periostin concentrations between subjects with a 25(OH)D deficient concentration (≤20 ng/mL) and subjects who did not have a deficient concentration (>20 ng/mL). In individuals with asthma, a 25(OH)D concentration of <30 ng/mL had no impact on eosinophilia, whereas IgE concentrations were associated with increased eosinophils, and the effect of periostin on eosinophilia was small although significant. Multivariate regression, including 25(OH)D concentration, CRP level, eosinophil counts, and sex, accounted for 7% of periostin variation in subjects with asthma. CONCLUSION In newly diagnosed pediatric asthma, 25(OH)D concentrations revealed a small although significant association with periostin levels but no effect on eosinophilia. A low vitamin D concentration may increase airway remodeling induced by inflammatory mediators, but further clinical studies aimed to explain the causal link between vitamin D insufficiency and asthma are needed.BACKGROUND Low 25-hydroxyvitamin D (25[OH]D) and asthma development may be related to airway remodeling and eosinophilia. Periostin is proposed as a key molecule that links remodeling and eosinophilic inflammation. OBJECTIVE We evaluated the association of 25(OH)D concentration with periostin, peripheral blood eosinophil counts, and immunoglobulin E (IgE) in children with newly diagnosed asthma. METHODS The study included 150 children: 110 with atopic asthma and 40 constituted a reference group. Fasting blood was collected for cell counts and serum for measurements of 25(OH)D, periostin, IgE, and C-reactive protein (CRP) concentrations. RESULTS Significantly lower 25(OH)D, elevated IgE concentrations, and eosinophil counts were found in children with asthma compared with the reference group (p = 0.0001). A lower forced expiratory volume in the first second of expiration percentage predicted value was associated with a lower 25(OH)D value in children with asthma. The bronchodilator reversibility was inversely related to serum 25(OH)D concentrations (R = -0.45, p = 0.029). The children with asthma and with a 25(OH)D deficient concentration (≤20 ng/mL) had higher concentrations of periostin (p = 0.035) and CRP (p = 0.01) than those with a sufficient 25(OH)D concentration (≥30 ng/L). Additional analysis revealed statistically significant differences (p = 0.013) when comparing periostin concentrations between subjects with a 25(OH)D deficient concentration (≤20 ng/mL) and subjects who did not have a deficient concentration (>20 ng/mL). In individuals with asthma, a 25(OH)D concentration of <30 ng/mL had no impact on eosinophilia, whereas IgE concentrations were associated with increased eosinophils, and the effect of periostin on eosinophilia was small although significant. Multivariate regression, including 25(OH)D concentration, CRP level, eosinophil counts, and sex, accounted for 7% of periostin variation in subjects with asthma. CONCLUSION In newly diagnosed pediatric asthma, 25(OH)D concentrations revealed a small although significant association with periostin levels but no effect on eosinophilia. A low vitamin D concentration may increase airway remodeling induced by inflammatory mediators, but further clinical studies aimed to explain the causal link between vitamin D insufficiency and asthma are needed.

Lymphocytes sensitivity to Fas stimulation in healthy and asthmatic children

The T cell hypothesis of asthma is based on the concept that the disease is driven and maintained by the persistence of a specialized subset of chronically activated T memory cells sensitized against an array of allergenic, occupational or viral antigens. Overreaction of CD4+ T cells in the peripheral blood and airway tissues is an invariant feature of asthma; therefore a potent mechanism for augmenting the number of activated T cells in this disease would be the resistance to the normally programmed pathway for cell death. The aim of the study was to evaluate the presence of apoptotic markers on peripheral blood lymphocytes from healthy and asthmatic children before and after stimulation with antiCD95 antibodies. The blood was collected from 21 children with atopic asthma suffering from allergic rhinitis because of house dust mite and/or grass pollen allergens and 8 healthy children matched for their age and sex. Blood was mixed with purified monoclonal antibody antiCD95 (Beckman Coulter), incubated for 24 hours and than stained with Annexin V andPI (Becton Dickinson). Prepared suspensions were analyzed with Cytomics FC 500 (Beckman Coulter) flow cytometer. Annexin V(+)/PI(-) cells were characterized as early apoptotic, Annexin V(+)/PI(+) as late apoptotic and Annexin V(-)/PI(+) as dead. In unstimulated sample from asthmatic children 21.09+/-11.20% cells were characterized as Annexin V positive/PI negative. After stimulation with antiCD95 Annexin V positive/PI negative cells constituted 18.72+/-9.42% of cells, p=0.1. In unstimulated sample from healthy children 11.69+/-6.70% cells were characterized as Annexin V positive/PI negative. In the sample stimulated with antiCD95 16.54+/-2.98% of cells were Annexin V positive/PI negative, p=0.02. There were no differences between results of late apoptotic and necrotic lymphocytes from healthy and asthmatic children. Performed research indicates that lymphocytes from asthmatic children are resistant to Fas mediated apoptosis.

Polymorphic Variants 279R and 668Q Augment Activity of Matrix Metalloproteinase-9 in Breath Condensates of Children with Asthma

Matrix metalloproteinase (MMP)-9 is involved in pathophysiology of asthma, mainly asthma-associated airway remodeling. Exhaled breath condensates (EBC) of asthmatics contain increased amounts of MMP-9 with activity higher, than in healthy controls. The increased activity of MMP-9 may originate from its excessive production and activation, but may also result from variations in MMP-9 structure, which are determined by single nucleotide polymorphisms (SNPs). In this pilot study we aimed to assess the possible influence of two functional MMP-9 polymorphisms, Q279R and R668Q, on enzymatic activity of MMP-9, measured in EBC of asthmatic children. The concentration and activity of MMP-9 were analyzed in EBC of 20 children with allergic asthma using specific standard ELISA and novel immunoenzymatic activity assay. The SNPs of MMP-9 were assessed using real-time PCR-based genotyping test. We have found that MMP-9 concentration in breath condensates of children with stable asthma was slightly higher in ELISA, than in the activity assay. Moreover, these results and activity-to-amount ratio have revealed some relationship with a presence of specific 279R and/or 668Q MMP-9 gene variants. Our observation suggests that at least in some patients MMP-9 hyperactivity may result from genetic predisposition, determined by polymorphic variants of MMP-9 gene. Moreover, it supports previous reports postulating significance of MMP-9 in pathogenesis of asthma. However, this issue still requires further studies.

Serum 25(OH)D status and lipid profile in children with newly diagnosed asthma

Background. The problem of the influence of hyperlipidemia on asthma was addressed several years ago. Systematic review and meta-analysis performed in the pediatric population on the association between vitamin D status and lipid profile components revealed discordant results and indicated that higher serum 25(OH)D is related to a more favorable lipid profile. Objective. We aimed to elucidate whether there was an association between vitamin D status and lipid profile components and apolipoprotein B in a sample of children with newly diagnosed atopic asthma. Methods. The study included 150 children aged 2–12 years. Atopic asthma was diagnosed in 110 children; 40 children constituted a reference group. Fasting blood was collected to measure 25(OH)D total, lipid profile and apolipoprotein B concentrations. Results. Children with asthma had significantly lower 25(OH)D (p < 0.0001) but similar lipid and apolipoprotein B concentrations. The proportions of hypercholesterolemia, hypertriglyceridemia and increased apoB concentrations were similar in both groups. HDL-C concentrations in asthmatic 25(OH)D-deficient children were higher compared with the children with sufficient levels (p = 0.05). ApoB concentration was lower in 25(OH)D-deficient compared with vitamin D sufficient asthmatics (p = 0.0008). Correlations between 25(OH)D concentration and lipids and apoB in asthmatics revealed gender differences. An inverse relationships between vitamin D and total cholesterol and HDL-C (R= –0.39, p < 0.05; R= –0.475, p < 0.001) were found in girls. In boys vitamin D correlated with LDL-C and apoB (R = 0.376, R = 0.498; p < 0.001). Conclusion. In children with asthma lower 25(OH)D had more favorable gender-dependent effect on the lipid profile. The association of serum 25(OH)D and lipid levels in children with asthma remains for further studies.