Cagatay Karaaslan

The effect of polymorphisms at the CD14 promoter and the TLR4 gene on asthma phenotypes in Turkish children with asthma

Background:  Endotoxin, with its potential to enhance type 1 immunity, is a significant player in the hygiene hypothesis. The combined effects of the genetic variants of various molecules in the endotoxin response pathway on asthma related phenotypes are largely unknown.

The effect of CD14-C159T genotypes on the cytokine response to endotoxin by peripheral blood mononuclear cells from asthmatic children

BACKGROUND A C-T polymorphism at position 159 in the promoter of CD14 (C-159T) modulates the cellular response to endotoxin and significantly influences total IgE levels. The effect of this genetic variant on the cytokine response of the inflammatory cells is incompletely understood. OBJECTIVE To investigate the effects of CD14-C159T genotypes on the response to endotoxin by peripheral blood mononuclear cells (PBMCs) in children with asthma. METHODS The PBMCs from asthmatic children with the TT (n = 11) and CC (n = 11) genotypes at the CD14 promoter were cultured in the presence of endotoxin, 100 ng/mL; concanavalin A, 10 microg/mL; or medium alone. Concentrations of soluble CD14 (sCD14), interleukin (IL) 1beta, IL-4, IL-10, IL-12, IL-13, interferon-gamma, and transforming growth factor beta were determined in culture supernatants by enzyme-linked immunosorbent assay, and the transcriptional differences were evaluated using reverse-transcriptase polymerase chain reaction. RESULTS Under unstimulated conditions, children with the TT genotype produced higher levels of sCD14 into the culture supernatant compared with children with the CC genotype (P = .03, Mann Whitney U test). Both IL-10 and IL-1beta concentrations were significantly higher in culture supernatants of children with the TT genotype after endotoxin stimulation (P = .02 and P = .009, respectively, by analysis of covariance [ANCOVA]). Messenger RNA expression was consistent with the results of protein concentration for IL-10 and sCD14. Concanavalin A stimulation resulted in lower levels of IL-4 in children with the TT genotype (P = .02, ANCOVA). CONCLUSION The genotype at the CD14 promoter C159T locus may significantly influence the cytokine response of PBMCs obtained from asthmatic children. Differences in IL-10 and IL-4 production by alternative genotypes may contribute to the observed genotype effect on total IgE.

The role of chemokines in exercise-induced bronchoconstriction in asthma

BACKGROUND The pathogenesis of exercise-induced bronchoconstriction in asthma is incompletely understood, and the role of chemokines has not been investigated. OBJECTIVE To investigate the involvement of the CC chemokines eotaxin, regulated upon activation normal T-cell expressed and secreted (RANTES), thymus and activation-regulated chemokine (TARC), and the CXC chemokine interferon-gamma-inducible protein 10 (IP-10) in exercise-induced bronchoconstriction. METHODS Four groups were enrolled: asthmatic children with positive (n = 15) and negative (n = 15) responses to exercise, children with cystic fibrosis (n = 14), and healthy children (n = 11). Levels of eotaxin, RANTES, TARC, and IP-10 were determined in plasma before, immediately after, and 6 and 24 hours after exercise challenge using enzyme-linked immunosorbent assay. Transcriptional activity was measured using reverse transcriptase-polymerase chain reaction. RESULTS Exercise did not induce any significant changes in systemic chemokine levels. A significant difference was observed only in the preexercise IP-10 levels among groups (P = .045). There was a significant difference in peripheral blood eosinophil counts among groups (P = .003). In asthmatic children with a positive response to exercise, there was an inverse correlation between eosinophil counts and eotaxin levels (r = -0.616; P = .01) and between forced expiratory volume in 1 second and TARC levels (r = -0.865; P = .001). Reverse transcriptase-polymerase chain reaction studies did not show any difference in the transcription of the chemokines. CONCLUSIONS Exercise does not cause any changes in the systemic expression of eosinophilic chemokines. Peripheral blood eosinophils may be a determinant of the exercise response, and eotaxin and TARC may be associated with eosinophil counts and forced expiratory volume in 1 second in children with a bronchoconstrictor response to exercise.

The genetic variants of thymic stromal lymphopoietin protein in children with asthma and allergic rhinitis.

Background: Thymic stromal lymphopoietin (TSLP) is expressed by airway epithelial cells and plays a key role in immunological events in asthma. Data on the genetic variants of TSLP and its association with asthma and allergic rhinitis are scarce. We aimed to investigate the effects of the genetic variants of TSLP in children with asthma and allergic rhinitis. Methods: The genetic variants of the TSLP gene were determined by sequencing 25 asthmatic and 25 healthy children. In an association study, a population of 506 asthmatics and 157 healthy controls was screened for the following single-nucleotide polymorphisms (SNPs): rs3806933 and rs2289276 in the promoter region; rs11466741, rs11466742, and rs2289278 in intron 2; rs10073816, rs11466749, and rs11466750 in exon 4, and rs11466754 in 3′-UTR. Results: In Multifactor Dimensionality Reduction analysis, presence of the rs11466749 AA genotype with atopy was significantly associated with a diagnosis of asthma (testing set accuracy: 0.720 and cross validation: 9/10). Two functional SNPs showed a gender-specific association with allergy, i.e. the rs3806933 CC genotype with asthma in boys (p = 0.032, nonsignificant after multiple testing) and the rs2289276 CC genotype with higher eosinophil numbers in asthmatic girls (p = 0.003). The presence of allergic rhinitis in asthmatic children strengthened the association of the rs11466749 GG genotype with asthma (p = 0.001), and rs2289276 was significantly associated with lower FEV1 levels in asthmatics without allergic rhinitis (p = 0.003). Conclusion: Variants in the gene encoding the TSLP protein may have differential effects on asthma phenotypes depending on gender, atopy, and the presence of allergic rhinitis.

Advances and highlights in allergen immunotherapy: On the way to sustained clinical and immunologic tolerance

&NA; Allergen immunotherapy (AIT) is an effective treatment strategy for allergic diseases and has been used for more than 100 years. In recent years, however, the expectations on concepts, conduct, statistical evaluation, and reporting have developed significantly. Products have undergone dose‐response and confirmative studies in adults and children to provide evidence for the optimal dosage, safety, and efficacy of AIT vaccines using subcutaneous and sublingual delivery pathways in large patient cohorts, ensuring solid conclusions to be drawn from them for the advantage of patients and societies alike. Those standards should be followed today, and products answering to them should be preferred over others lacking optimization and proof of efficacy and safety. Molecular and cellular mechanisms of AIT include early mast cell and basophil desensitization effects, regulation of T‐ and B‐cell responses, regulation of IgE and IgG4 production, and inhibition of responses from eosinophils, mast cells, and basophils in the affected tissues. There were many developments to improve vaccination strategies, demonstration of new molecules involved in molecular mechanisms, and demonstration of new biomarkers for AIT during the last few years. The combination of probiotics, vitamins, and biological agents with AIT is highlighting current advances. Development of allergoids and recombinant and hypoallergenic vaccines to skew the immune response from IgE to IgG4 and regulation of dendritic cell, mast cell, basophil, innate lymphoid cell, T‐cell, and B‐cell responses to allergens are also discussed in detail.