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

Performance of Eosinophil Cationic Protein as a Biomarker in Asthmatic Children

BACKGROUND

Although blood eosinophils are a frequently used marker of type 2 inflammation in children with asthma, their sensitivity is relatively poor. Additional markers of type 2 inflammation are needed.

OBJECTIVE

We hypothesized that plasma concentrations of eosinophil cationic protein (ECP), a marker of eosinophil activation, would be useful for detection of type 2 inflammation and would predict poorer asthma outcomes over 1 year.

METHODS

Children and adolescents 6 through 17 years (N = 256) with confirmed asthma completed a baseline visit and a follow-up visit at 12 months. A subset also underwent systemic corticosteroid responsiveness testing with intramuscular triamcinolone. Outcome measures at 12 months included uncontrolled asthma, lung function, and asthma exacerbations treated with systemic corticosteroids.

RESULTS

Plasma ECP concentrations ranged from 0.03 to 413.61 ng/mL (median, 6.95 ng/mL) and were consistently associated with other markers of type 2 inflammation. At baseline, children in the highest ECP tertile had poorer asthma control, more airflow limitation, and more exacerbations, but also had greater symptom improvement with intramuscular triamcinolone. At 12 months, associations between the highest ECP tertile and exacerbations, but not lung function or asthma control, persisted after covariate adjustment. However, the sensitivity of ECP was modest and was not markedly different from that of blood eosinophil counts.

CONCLUSION

Plasma ECP concentrations may be a useful marker of type 2 inflammation in children and may help identify those children at highest risk for recurrent exacerbations who could benefit from corticosteroid treatment. However, additional markers may be needed to improve sensitivity for outcome detection.

Which biomarkers are effective for identifying Th2-driven inflammation in asthma?

Recognition of asthma as a heterogeneous disease revealed different potential molecular targets and urged the development of targeted, customized treatment modalities. Evidence was provided for different inflammatory subsets of asthma and more recently, further refined to T helper (Th)2-high and Th2-low subphenotypes with different responsiveness to standard and targeted pharmacotherapy. Given these differences in immunology and pathophysiology, proof of concept studies of novel treatment modalities for asthma should be performed in adequate, well-defined phenotypes. In this review, we describe both existing and novel biomarkers of Th2-inflammation in asthma that can be applied to classify asthma subphenotypes in clinical studies and for treatment monitoring.

Peripheral T cell functions correlate with the severity of chronic obstructive pulmonary disease

Adaptive immune processes have been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). We hypothesized that peripheral T cell abnormalities may be present in afflicted patients. We tested this hypothesis by characterizing circulating T cells in COPD patients and correlated these findings with disease severity, smoking status, and use of inhaled glucocorticosteroids (ICS). Compared with normal controls, a lesser proportion of peripheral CD4 T cells from COPD subjects produced IL-10, whereas the CD8 T cells from these patients were more often activated and more frequently produced both IFN-gamma and IL-4. COPD severity was significantly and inversely associated with the proportion of circulating CD4 T cells and directly correlated with CD4 production of IL-2, as well as frequency of CD8 T cell activation and CD8 IFN-gamma production. Adjustments for current smoking status and ICS use by linear regression showed independent, and generally inhibitory, effects of these clinical variables on the abnormal T cell functions of these patients. We conclude that circulating T cells from COPD patients are abnormally activated and elaborate proinflammatory mediators with admixed features of Th1 and Th2 responses. Furthermore, many of these effector processes are significantly correlated with disease severity. These findings further implicate adaptive immune processes in COPD progression and indicate that facile assays of peripheral lymphocytes may provide useful insights into disease mechanisms. Current smoking and ICS use had independent effects on T cell functions among the COPD subjects, illustrating the importance of controlling for clinical parameters as covariates in immunological studies of patients afflicted with this disease.

Squamous cell carcinoma-related antigen in children with acute asthma

BACKGROUND

Increased serum levels of squamous cell carcinoma-related antigen (SCCA) have been observed in patients with allergic disorders, such as atopic dermatitis and bronchial asthma. T(H)2 cytokines, which are known to be involved in the pathogenesis of allergic disorders, stimulate new synthesis of SCCA in cultured human airway epithelial cells.

OBJECTIVE

To investigate whether SCCA levels increase during acute exacerbations of asthma in children and whether the T(H)2 cytokines, interleukin 4 (IL-4) and IL-13, are associated with SCCA levels.

METHODS

Serum levels of SCCA, IL-4, and IL-13 were measured by enzyme immunoassay during the acute phase of an asthma exacerbation (on hospital admission) and in the recovery phase (after symptoms had subsided).

RESULTS

In the 35 children who participated in this study, serum levels of SCCA were significantly elevated in the acute phase (mean +/- SD, 3.09 +/- 2.03 ng/mL) compared with the recovery phase (mean +/- SD, 1.47 +/- 0.64 ng/mL) of an asthma exacerbation (P < .001). In 12 children, the IL-13 levels were observed to correlate with SCCA levels during the recovery phase (r = 0.68, P = .02) but not during the acute phase of an asthma exacerbation.

CONCLUSIONS

Serum SCCA levels increase during the acute phase of an asthma exacerbation. During this phase, the increased synthesis of SCCA is not associated with IL-13 but rather mediated by other undefined stimuli. IL-13 may contribute to the basal production of SCCA in asthmatic children.

Comparative effect of triamcinolone, nedocromil and montelukast on asthma control in children: A randomized pragmatic study

Asthma severity can be judged by measurements of symptoms, lung function, and medication requirements. The objective was to compare the effect of a 4-wk monotherapy with low-dose triamcinolone, montelukast and nedocromil on asthma control, lung function, eosinophil blood count, and bronchial hyper-reactivity in children with mild to moderate asthma allergic to dust mite. Two hundred fifty-six children, aged 6-18 yr, with mild to moderate asthma, participated in an 8-wk study. This was a three-arm, randomized no blinding or placebo pragmatic trial comparing the effect of triamcinolone acetonide (400 microg/day), inhaled nedocromil and montelukast sodium on clinical parameters of asthma [score, forced expiratory volume in 1 s (FEV(1))], PC20H, and eosinophil blood count. Two hundred forty-six children completed the study. After 4 wk of treatment with triamcinolone and montelukast, FEV(1) and PC20H significantly increased, and mean total symptoms score and mean number of eosinophil count in serum significantly decreased. Triamcinolone had a stronger effect on PC20H than montelukast. Nedocromil improved total asthma symptoms score and lung function. There was a reduction in the daytime and night-time symptom scores after treatment with all three drugs. Triamcinolone and montelukast had a stronger effect on asthma symptoms than nedocromil. There were statistically significant differences in reduction of nocturnal asthma symptoms between the triamcinolone and nedocromil groups (p < 0.001) and between montelukast and nedocromil (p = 0.001) groups, but not between the triamcinolone and montelukast groups. There was a reduction in beta-agonists use after treatment with all three drugs, with the strongest effect of triamcinolone. The study showed the strongest effect of low-dose inhaled steroids on clinical symptoms, lung function, bronchial hyper-reactivity and eosinophil blood count when compared to other asthma medications.

CD34+ cells in peripheral blood of healthy human beings and allergic subjects: clue to acute and minimal persistent inflammation

BACKGROUND

There is compelling evidence that hemopoietic precursor cells (HPC) play a crucial role in establishing cellular inflammation in allergic diseases. Increased levels of circulating CD34+ HPC committed to the myeloid lineage have been extensively reported in allergic rhinitis, asthma and eczema, whereas CD34+ cells have been identified within the cellular infiltrates of tissues, at peripheral sites of inflammation.

METHOD

We conducted a pilot study to evaluate CD34+ traffic in the peripheral blood of 22 consecutive patients (13 men and nine women; mean age 28.9 years), independently of treatment. The patients presented rhinitis, asthma, eczema, urticaria and adverse food reactions of suspected allergic origin. Allergic reactions were extrinsic in 18 patients and intrinsic in four. In 12 patients who underwent sublingual specific immunotherapy, CD34+ cells were quantified at enrollment (T0), one year later (T1) and two years later (T2). The severity of symptoms was graded on a five-point scale (0 = absence of symptoms and 4 = severe symptoms). Twenty healthy human subjects (10 men and 10 women; mean age 24.5 years) were evaluated as controls. To obtain information about the total amount of circulating HPC, independently of the lineage commitment (Lin+/-) and the degree of differentiation (CD34bright/dim), we used a modification of the Milan protocol of peripheral blood CD34+ cell estimation. The cells were analyzed using a BD FACScan or FACSCalibur and the results were expressed as the percentage of positive cells.

RESULTS

CD34+ cell traffic in the control group was very low since all values were < 0.10 (median value: 0.03 %). Values in the patient group were increased in both extrinsic and intrinsic forms with a median value of 0.25 % (interquartile range: 0.13- 0.33 %). The relationship between CD34+ traffic and the severity score was highly significant (Spearman's rho = 0.954; test of Ho: CD34; independent score: Pr > t = 0.000).

CONCLUSIONS

The data reported herein suggest that the method employed is effective in assessing acute allergic inflammation, as well as minimal persistent inflammation underlying an asymptomatic clinical condition. Evaluation of CD34bright/dim peripheral traffic, if confirmed by the outcomes of a multicenter study currently being planned together with traditional study of circulating IgE, could be a reliable non-invasive laboratory tool for monitoring allergic inflammation.