Do inhaled corticosteroids reduce serum IgE levels? The answer is maybe but how relevant is the question?

Inhaled steroid inhibits development of total and mite IgE

Serum levels of total immunoglobulin E (IgE) and allergen-specific IgE are related to asthma severity and risk factors for persistent asthma in childhood wheezing. Inhaled corticosteroids (ICS) have been the most effective therapy in children with asthma, as well as in adults. The serum levels of total and mite specific IgE in children with asthma and the effects on IgE levels of beclomethasone dipropionate (BDP) treatment on IgE levels in asthmatic children were investigated. First, a cross-sectional study of 255 children with asthma was carried out to measure IgE levels. Children under three years of age with asthma who were negative for Df-specific IgE were then treated with BDP or disodium cromoglycate (DSCG) as controls for one year. Serum IgE levels, numbers of eosinophils in peripheral blood and clinical variables were determined before and after treatment. After one-year DSCG treatment, the total IgE levels increased significantly, whereas the levels remained the same during BDP treatment. Five of 22 (23%) patients in the DSCG-treated group became positive for Df-specific IgE; however, only one of 13 (8%) in the BDP-treated group became positive. Taken together, ICS therapy may modulate the levels of total IgE and allergen-specific IgE.

Anti-bacterial IgE in the antibody responses of house dust mite allergic children convalescent from asthma exacerbation

Background Atopic sensitization to the house dust mite (HDM) is associated with altered antibody responses to the nasopharyngeal colonizing bacterium Haemophilus influenzae and children admitted to the emergency department for asthma exacerbation have reduced IgG responses to HDM allergens.

Objective To investigate anti‐bacterial and anti‐allergen antibody responses during convalescence from asthma exacerbation and differences found in exacerbations associated with and without viral infection.

Results IgE antibodies to the P6 bacterial antigen increased in 60% of sera during convalescence and for many children achieved titres as high as IgE titres to allergens. In contrast IgE anti‐HDM titres declined during convalescence. The anti‐bacterial IgE titres were the same in subjects with and without virus infection while the anti‐HDM IgE declined more rapidly in virus‐infected subjects. IgG titres to the major HDM allergens showed no consistent increase and the overall IgG anti‐HDM titres even declined in subjects without a virus infection. Anti‐bacterial IgG antibodies in contrast to IgE did not change. Patients with frequent episodic or persistent asthma had similar IgE anti‐bacterial titres to patients with infrequent asthma during the acute phase, although they had reduced IgG titres to both the bacteria and the HDM.

Conclusions During the period following an acute exacerbation of asthma there was a marked and specific increase in anti‐bacterial IgE compared with a reduced IgE response to HDM. This provides further support for the concept of T‐helper type 2 responses to bacterial antigens playing a role in asthma pathogenesis.

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 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.

OBJECTIVE

To investigate the effects of the genetic variants of CD14 and TLR4 genes on asthma phenotypes in a large number of asthmatic children.

METHODS

613 asthmatic children were genotyped at the CD14-C159T, TLR4-A896G and TLR4-C1196T loci. IgE, eosinophil numbers and FEV1 were compared in 327 children who were not on any controller medications and were symptom free. Multivariate logistic regression was used to determine the factors associated with total IgE.

RESULTS

Among children with atopic asthma, total IgE levels were significantly different among the three genotypes in the co-dominant model [CC: 435 kU/l (interquartile range: 146-820); CT: 361 (140-710); TT 204 (98-435), P = 0.035]. TT genotype was significantly and independently associated with lower IgE levels (OR: 0.5 95%; CI = 0.28-0.90, P = 0.021). Both TLR4-A896G and TLR4-C1196T polymorphisms were more frequent in the mild asthma group with atopy (P = 0.032, 0.018, respectively). The combined effects of the genetic variants in CD14 and TLR4 genes did not improve the observed associations.

CONCLUSION

Our study demonstrates that the CD14-C159T promoter variant influences total IgE levels and also indicates that the T allele has a more profound effect on total IgE in children with atopic asthma. Polymorphisms in the TLR4 gene may be associated with milder forms of disease in atopic asthmatics in the population studied.