Serum concentration of C-reactive protein is not a good marker of bronchial hyperresponsiveness

Evaluation of high-sensitivity serum CRP levels compared to markers of airway inflammation and allergy as predictors of methacholine bronchial hyper-responsiveness in children

BACKGROUND

Bronchial hyper-responsiveness assessed by the methacholine challenge test (MCT) may aid in the diagnosis of asthma, while a negative MCT can help in excluding the diagnosis. Laboratory measures that predict the results of MCT are expected to reduce the number of procedures. We evaluated the capacity of serum high-sensitivity C-reactive protein (hs-CRP) to predict positive or negative MCT in school-aged children and compared it to a marker of airway inflammation, fractional exhaled nitric oxide (FeNO), and markers of allergic sensitization, immune globulin E (IgE) and peripheral blood eosinophils.

PATIENTS AND METHODS

Children aged 6-18 years referred for MCT were included in the study. The results of the MCT were compared to hs-CRP levels and FeNO levels, IgE, and peripheral blood eosinophil counts.

RESULTS

Of the 131 children assessed, 63 (48 %) patients had positive MCTs (Group I), and 68 (52 %) had negative MCTs (Group II). The best cut-off values to predict a positive MCT by receiver-operating characteristic curves were: 23 ppb for FeNO, 120 IU/mL for IgE, and 500/mL for eosinophils; no cut-off value was found for hs-CRP. The odds ratio for a positive MCT with the above cut-off points were 2.43 (1.05-5.61) for FeNO, 2.4 (1.01-5.74) for IgE, 3.32 (1.13-9.75) for eosinophils, and NS for hs-CRP. No correlation was found between hs-CRP and FeNO, IgE, or eosinophil levels.

CONCLUSIONS

hs-CRP levels were not helpful, while FeNO, IgE, and eosinophils were useful in the prediction of methacholine bronchial hyper-responsiveness in our group of children.

Effect of inhaled corticosteroids on systemic inflammation in asthma

Background:

Recent research using serum high sensitivity C-reactive protein (hs-CRP) has evidenced existence of low grade systemic inflammation in asthmatics whose correlation with various clinical indices is not fully studied.

Objective:

To investigate the relationship between systemic inflammation and various clinical and treatment characteristics of asthma.

Materials and Methods:

Forty asthmatics (22 steroid inhaling and 18 steroid naïve) and 40 healthy subjects matched for age and sex were examined cross-sectionally. Along with clinical assessment, serum hs-CRP levels were measured for all subjects using latex enhanced immunoturbidometry method.

Results:

Serum hs CRP levels were significantly higher in steroid naïve asthmatics when compared to normal subjects (0.93 ± 1.18 vs 0.24 ± 0.31 mg/dL, respectively; Mann-Whitney U test, P < 0.001). This association persisted after adjusting for age, gender, body mass index (BMI), and socioeconomic status (adjusted odds ratio 10.47; 95% CI 1.88-58.3; P < 0.01). Steroid inhaling asthmatics had serum hs-CRP levels comparable with control group (0.17 ± 0.18 vs 0.24 ± 0.31 mg/dL respectively, P > 0.05). Among the clinical and treatment related variables, duration of inhaled steroids usage alone correlated significantly with serum hs-CRP levels (Pearson correlation coefficient r = 0.449, P < 0.05), which was independent of age, BMI, duration of illness, and frequency of emergency visits.

Conclusion:

This study confirms the existence of low grade systemic inflammation in asthma which is effectively controlled by inhaled steroids. Such an effect of inhaled steroids appears to be more pronounced in recent users than that of long-term users, possibly due to lower adherence rate among the latter.

The fractional exhaled nitric oxide and serum high sensitivity C-reactive protein levels in cough variant asthma and typical bronchial asthma

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is known to be a good marker of airway eosinophilic inflammation in bronchial asthma. Recently, serum high sensitivity C-reactive protein (hs-CRP) has been shown to be also useful to detect the airway inflammation.

METHODS

Newly diagnosed 90 cough variant asthma and 92 bronchial asthma patients were enrolled. FeNO, serum hs-CRP, pulmonary function tests, bronchial hyperresponsiveness, IgE and sputum eosinophils ratio were compared. Ninety healthy control subjects were set for FeNO and serum hs-CRP normal range reference. We have compared the clinical utilities of FeNO and serum hs-CRP to differentiate bronchial asthma and cough variant asthma.

RESULTS

FeNO was significantly higher in bronchial asthma (92.6 ± 85.5ppb) than in cough variant asthma (35.6 ± 43.3; p < 0.001) and both were significantly higher than normal range (18.0 ± 6.4, p < 0.001, respectively), and in differentiating between the two groups showed a sensitivity of 0.69 and a specificity of 0.73 at the cutoff value of 28 ppb. Serum hs-CRP did not differ significantly between bronchial asthma (723 ± 1162ng/ml) and cough variant asthma (558 ± 758) even if both were significantly higher than normal range (345 ± 401, p < 0.01 and p < 0.05 respectively).

CONCLUSIONS

FeNO is more useful than serum hs-CRP in differentiating patients with bronchial asthma from those with cough variant asthma, and healthy persons.

High-sensitivity C reactive protein as a biomarker for grading of childhood asthma in relation to clinical classification, induced sputum cellularity, and spirometry

BACKGROUND

Asthma is the most common chronic inflammatory disease in childhood and some reports have demonstrated systemic inflammation. The relevance of high-sensitivity assays for C-reactive protein (hs-CRP), which are known to be a sensitive marker of low-grade systemic inflammation, has not been fully studied in childhood asthma.

AIM OF STUDY

This cross sectional case-control study aimed at evaluating serum hs-CRP in asthmatic children with different grades of severity and control.

METHODS

Serum hs-CRP, sputum cytology study, and forced expiratory volume in 1 sec (FEV1) % of predicted for age and sex were estimated in 60 asthmatic children (30 uncontrolled steroid-naïve, and 30 controlled on inhaled steroid). They were recruited from Pediatric Chest Clinic, Children's Hospital, Ain Shams University. Sixty healthy children-age and sex-matched were included as a control group.

RESULTS

Serum hs-CRP concentrations were significantly higher in asthmatics than in controls with a median of 1.93 mg/L and 0.24 mg/L, respectively. Serum hs-CRP levels were significantly higher in uncontrolled steroid-naïve asthmatics than those controlled on inhaled steroid with a median of 3.15 mg/L and 1.55 mg/L, respectively. Serum hs-CRP showed a sensitivity of 72% and a specificity of 93%.

CONCLUSIONS

Despite that pulmonary function tests and clinical classification are the gold standard for grading of asthma, hs-CRP can be considered as a new marker for assessment of different grades of asthma severity and control. It can be used for indirect detection and monitoring of airway inflammation, disease severity, and response to steroid treatment in asthmatic children.