Soluble interleukin-2 receptor and interleukin-4 in sera of asthmatic children before and after a prednisolone course

The soluble IL-2 receptor α/CD25 as a modulator of IL-2 function

The pleiotropic cytokine interleukin-2 (IL-2) is an integral regulator of healthy and pathological immune responses, with the most important role in regulating the homeostasis of regulatory T cells. IL-2 signalling involves three distinct receptors: The IL-2 receptor α (IL-2Rα/CD25), IL-2Rβ, and IL-2Rγ/γc . While IL-2Rβ and γc are essential for signal transduction, IL-2Rα regulates the affinity of the receptor complex towards IL-2. A soluble form of the IL-2Rα (sIL-2Rα) is present in the blood of healthy individuals and increased under various pathological conditions. Although it is known that the sIL-2Rα retains its ability to bind IL-2, it is not fully understood how this molecule affects IL-2 function and thus immune responses. Here, we summarize the current knowledge on the generation and function of the sIL-2Rα. We describe the molecular mechanisms leading to sIL-2Rα generation and discuss the different IL-2 modulating functions that have been attributed to the sIL-2Rα. Finally, we describe attempts to utilize the sIL-2Rα as a therapeutic tool.

High serum arginase I levels in asthma: its correlation with high-sensitivity C-reactive protein

BACKGROUND

Much attention has been directed to the induction of arginase I in the lung of asthmatic mice. However, there is no agreement on the changes of serum arginase activity in asthmatic patients among previous studies.

OBJECTIVES

The aim of this study was to evaluate the clinical relevance of serum arginase I in asthmatic patients.

METHODS

Serum arginase I was examined cross-sectionally in non-smoking asthmatic patients (n = 23) and healthy individuals (n = 30) using enzyme-linked immunosorbent assay (ELISA) and its correlations with several clinical parameters were investigated.

RESULTS

Serum levels of arginase I were significantly increased in asthmatic patients (mean ± SD 67.4 ± 41.0 ng/mL) compared with healthy controls (27.2 ± 12.9 ng/mL). In healthy controls, a difference in arginase I levels was not observed between sex groups but was observed between age groups. In asthmatic patients, serum arginase I levels were not different between groups of age, sex, and inhalation steroid therapy but were different between groups of atopic status. Non-atopic asthmatic patients revealed significantly high serum arginase I levels compared with atopic asthmatic patients and healthy controls although no difference was observed between atopic asthmatic patients and healthy controls. Spearman's correlation analysis showed that serum arginase I level had a significant negative correlation with age and a positive correlation with red blood cell numbers in healthy controls, whereas in asthmatic patients, it had significant positive correlations with alanine aminotransferase (ALT), high-sensitivity C-reactive protein (hs-CRP) and a negative correlation with immunoglobulin-E (IgE).

CONCLUSIONS

High serum arginase I levels in asthmatic patients may be associated with airway inflammation in non-atopic asthma.

T cell and eosinophil activation in mild and moderate atopic and nonatopic children's asthma in remission

BACKGROUND

Inflammation in the pathogenesis of asthma is associated with products of activated T cells and eosinophils. The aim of this study was to determine whether ongoing inflammation persists in children with different phenotypes of asthma despite the disease in remission.

METHODS

Serum samples were collected from 68 children with atopic or nonatopic asthma in remission and from 15 healthy children. Soluble interleukin-2 receptor (sIL-2R), IL-2 and IL-4 were examined by using an enzyme-linked immunosorbent assay. Total and specific immunoglobulin E, and eosinophil cationic protein (ECP) were analysed by fluoroimmunoassay (Pharmacia CAP System).

RESULTS

In patients with moderate persistent atopic asthma, sIL-2R was increased significantly when compared with mild persistent atopic asthma (P < 0.05). No changes of sIL-2R were seen in nonatopic asthmatics compared with atopics and controls. The level of IL-2 was elevated in moderate persistent atopic and nonatopic asthmatic children compared with controls (P < 0.05 and P < 0.05 respectively) and compared with mild persistent atopic asthmatics and mild persistent nonatopic asthmatics (P < 0.05 in both cases). The levels of IL-4 in most patients and controls remained below the sensitivity of the assay. Eosinophil cationic protein levels in moderate persistent atopic and nonatopic asthmatics were significantly higher than in mild persistent asthma severity cases (P < 0.001 and P < 0.01 respectively) and in healthy children (P < 0.01 in both cases).

CONCLUSION

Changes in the concentration of sIL-2R, IL-2 and ECP reflect increased T cell and eosinophil activity in relation to the level of severity of asthma in atopic and nonatopic children, thereby proving the presence of persistent inflammation despite the absence of disease symptoms.

[Comparative efficacy of oral deflazacort versus oral prednisolone in children with moderate acute asthma]

OBJECTIVES

To assess the efficacy and tolerability of oral deflazacort versus oral prednisolone in acute moderate asthma in children.

PATIENTS AND METHODS

We performed a prospective, randomized, parallel group trial of children aged 6 to 14 years old with a diagnosis of asthma who presented to the pediatric emergency department for moderate asthma exacerbation. All patients were administered short-acting beta2-adrenergic agonists. The intervention groups received either oral deflazacort (1.5 mg/kg) or prednisolone (1 mg/kg) for 7 days. The primary outcome measure was forced expiratory volume in 1 second (FEV1) and secondary outcome measures were pulmonary symptom score index, peak expiratory flow rate (PEFR), hospitalization rate and the use of rescue beta2-agonists. Patients were evaluated at the start of treatment (visit 1), on day 2 (visit 2) and on day 7 (visit 3).

RESULTS

Of the 54 children enrolled, two were hospitalized on visit 2 (one from each group). Baseline clinical data were similar in both groups: FEV1: 53 and 51 %; bronchodilator test: 119 and 121 %; PEFR: 169 and 165 L/min; symptom score: 6 and 6.5 for the deflazacort and prednisolone groups, respectively. On visit 2, all measures improved: FEV1: 122.2 and 126.5 % (p < 0.05); PEFR: 164 and 149 L/min (p < 0.05); symptom score: -4.4 and -3.8 (p < 0.05), without significant differences between groups. On visit 3 all variables continued to show improvement: FEV1: 133.2 and 132.5 % (p < 0.05); PEFR: 1115.7 and 187.6 L/min (p < 0.05); symptom score: -5.4 and -5.9 (p < 0.05), without significant differences between groups. No adverse effects were reported.

CONCLUSIONS

Deflazacort and prednisolone show similar efficacy in improving pulmonary function and in producing clinical improvement in the management of acute moderate asthma in children.

Treating exacerbations of asthma in children: the role of systemic corticosteroids

OBJECTIVE

To review the use of systemic corticosteroids to treat recurrent, acute asthma episodes in children, with a focus on the role of oral corticosteroids.

METHODS

A comprehensive review of the literature was performed using the Medline database (January 1966-October 2002) and the Embase database (January 1980-August 2002).

RESULTS

The significant findings of 17 selected, controlled clinical trials of oral corticosteroids (OCSs) for acute exacerbations of asthma in children, compared with placebo or with other formulations of corticosteroids, can be summarized as follows: 1) OCSs are effective for the outpatient treatment of acute asthma, 2) pulmonary function tests may not be the best means of assessing the efficacy of OCSs for acute asthma, 3) early administration of OCSs for acute asthma reduces hospitalizations, 4) the critical factor for a positive outcome is early administration of the corticosteroid, and 5) OCSs are preferred for the outpatient treatment of acute asthma.

CONCLUSIONS

Early treatment of acute asthma symptoms with OCSs in children with a pattern of recurrent acute asthma may decrease the severity of acute asthma episodes and reduce the likelihood of subsequent relapses. Attention should be given to identifying these children and standardizing a treatment approach based on accepted, consistent definitions of what constitutes an asthma exacerbation and recurrence. A suggested protocol is described.

Influence of different dosage schedules of inhaled fluticasone propionate on peripheral blood cytokine concentrations in childhood asthma

BACKGROUND

Asthma is characterized by eosinophilic airways inflammation with elevated levels of IL-4, IL-5 and sICAM-1, and reduced levels of IL-10 and IFN-gamma. Inhaled corticosteroids powerfully reduce airways inflammation.

OBJECTIVE

To investigate if eosinophil counts, serum eosinophilic cationic protein (ECP) and sICAM-1 levels, as well as serum and production of cytokines (IL-4, IL-5, IL-10, IFN-gamma) by peripheral blood monocytes (PBMCs) are useful markers to monitor therapy with inhaled fluticasone propionate (FP) in asthmatic children.

METHODS

In a double-blind, 1-year study, 55 asthmatic children (aged 6-10 years) stopped inhaled corticosteroids for a mean period of 24 days and were randomized to receive either FP 200 microg/day (constant dose group), or a starting dose of FP 1000 microg/day with two monthly reductions to 500, 200 and 100 microg/day (stepdown group). Hyper-responsiveness, symptom scores and blood sampling were performed at 2-month intervals.

RESULTS

Symptoms and hyper-responsiveness improved significantly in both treatment groups after reintroduction of FP. Eosinophil counts decreased significantly more during the first 2 months of FP in the stepdown group than in the constant dose group (P = 0.03). We found a trend towards a dose-dependent response in changes of eosinophil counts and serum ECP levels during treatment. Serum IL-4 and IL-5 levels were undetectable in the majority of children. No significant effect of the dose of FP on the release of IL-4, IL-5, IL-10 or IFN-gamma by Con A stimulated PBMCs was found. sICAM-1 levels did not significantly differ at any time point between the two groups.

CONCLUSION

Serum ECP as well as peripheral blood eosinophils, cytokine production by PBMCs and sICAM-1 levels are insensitive markers in titrating and monitoring therapy with inhaled corticosteroids over a wide dose range in childhood asthma.

Markers of allergic inflammation in peripheral blood of children with asthma after treatment with inhaled triamcinolone acetonide

BACKGROUND

It is important to monitor inflammation regularly in asthma in addition to clinical symptoms, and there is a great need for noninvasive tests that could routinely be used in clinical practice.

OBJECTIVE

Our hypothesis was that the improvement of clinical parameters, together with decreased airway responsiveness, could be correlated with changes in the levels of serum markers of inflammation after a 4-week treatment with triamcinolone.

METHODS

In this double-blind, randomized, placebo-controlled trial, 48 children, aged 6 to 18 years, with mild to moderate atopic asthma, were randomly allocated to receive triamcinolone or matching placebo for 4 weeks. The following parameters were measured: the symptom score, forced expiratory volume in 1 second (FEV1), provocative concentration of histamine causing a 20% fall in FEV1 (PC20) for histamine and peripheral blood eosinophil count, serum levels of the inflammatory markers eosinophil cationic protein (ECP), soluble receptor of interleukin-2 (sIL-2R), interleukin-4, soluble intercellular adhesion molecule-1 before and after treatment.

RESULTS

The clinical parameters significantly improved after treatment with triamcinolone; the mean value of FEV1 changed from 74% of predicted value before, to 90% of predicted after treatment (P < 0.001). PC20 for histamine after treatment with triamcinolone increased significantly from the mean value 2.5 mg/mL to 4.7 mg/mL (P < 0.001). Treatment with triamcinolone significantly (P < 0.05) decreased serum levels of all the measured inflammatory markers. The mean concentration of eosinophil blood count was 380 and 261 cells/mm3; ECP, 83 and 58 ng/mL; serum sIL-2R, 734 and 487 pg/mL; soluble intercellular adhesion molecule-1, 266 and 210 ng/mL, before and after treatment, respectively. The values of interleukin-4 were low and close to the sensitivity of the assay. A significant correlation was found between ECP and sIL-2R levels before and after treatment with triamcinolone.

CONCLUSIONS

A significant decrease of all the measured serum parameters was observed after treatment with triamcinolone; however, no significant correlation was found among any of those parameters and clinical markers of disease severity (such as FEV1 or PC20H).