Role of airway lactoperoxidase in scavenging of hydrogen peroxide damage in asthma

Hydrogen peroxide (H(2)O(2)) that is mainly generated by neutrophils and eosinophils in asthma is known to be damaging to the airway and to contribute to airway inflammation. The purpose of the present study was to determine the contribution and the role of lactoperoxidase in scavenging airway hydrogen peroxide, in order to propose a therapeutic approach for asthma. The study was an open clinical trial. Twenty-five nonsmoking asthmatic patients were included in the study. Of them, 16 patients (64%) were male and 9 (36%) were female, with age ranging from 29 to 48 years (45.13 +/- 4.6). Of the 25 patients included in the study, only 16 patients completed the study; and they were eligible for analyses. Exhaled breath condensate was collected from all patients at the time of entering the study; and 2, 4 and 8 weeks later. All patients received dapson as a lactoperoxidase inhibitor at a dose of 50 mg daily for 8 weeks. The study was conducted during the period from January 2006 to end of October 2006. H(2)O(2) concentration was determined by an enzymatic assay. Determination of exhaled breath condensate for hydrogen peroxide concentration after 8 weeks of dapson usage indicated an increase (1.05 +/- 0.36 microM; 95% CI, 0.89-1.21) as compared to that at baseline (P < 0.0001), 2 weeks (P < 0.001) and 4 weeks (P > 0.05). The increase in hydrogen peroxide concentration in exhaled breath condensate after inhibition of lactoperoxidase by dapson advocates a potential role for lactoperoxidase in scavenging of hydrogen peroxide in asthmatic airway.

The predictive value of eosinophil cationic protein and lactate dehydrogenase in asthma: a comparative study of serum versus sputum

BACKGROUND

: Serum and sputum eosinophil cationic protein (ECP) levels are correlated with asthma disease severity.

OBJECTIVE

: To establish a diagnostic accuracy of ECP and lactate dehydrogenase (LDH) in serum (indirectly) and sputum (directly) as inflammatory markers in asthma.

PATIENTS AND METHODS

: In a cross sectional study, 76 asthmatic patients with exacerbation were enrolled in the study. ECP was determined using enzyme linked immuno-assay.

RESULTS

: Asthmatic patients compared with control subjects, had a significant higher levels of ECP and LDH in sputum. Both sputum and serum ECP and LDH were reduced significantly with prednisolone treatment. FEV1 was inversely correlated with sputum ECP, serum ECP, and sputum LDH. A significant positive correlation was noted between sputum ECP and sputum LDH. Serum LDH does not demonstrate any significant correlations with other variables. The area under receiver operating characteristic curve showed that sputum ECP (0.92) was a significantly an accurate marker more than serum ECP (0.81), sputum (0.80) LDH, and serum (0.65) LDH. Furthermore, the area under curve was lower for serum ECP (0.81) than that for sputum ECP (0.92). However, serum ECP (0.81) was more accurate marker than serum LDH (0.65).

CONCLUSION

: Serum and sputum ECP as eosinophilic inflammatory markers are associated with poor asthma control. Sputum ECP and LDH were significantly an accurate markers more than serum ECP and LDH.

The predictive value of IgE as biomarker in asthma

BACKGROUND

The evidence for a causal relationship between allergens and asthma depends on epidemiologic findings showing a strong association between specific immunoglobulin E (IgE) antibodies or total IgE and asthma.

OBJECTIVE

To clarify the relationship between total serum IgE levels and asthma.

STUDY DESIGN

A cross-sectional study.

PATIENTS AND METHODS

A total of 562 asthmatic patients were included in the study, and their age range was from 17 to 52 years. The subjects included in the study were outpatients from the Asthma and Allergy Centre or Samara General Hospital outpatients Clinic. The diagnosis of asthma was performed by a specialist physician and was established according to the National Heart Blood and Lung Institute/World Health Organization (NHLBI/WHO) workshop on the Global Strategy for Asthma.

RESULTS

This study indicated that mean serum IgE level was 554 +/- 447 IU/mL in asthmatic patients, while that of the control population was 69 +/- 33 IU/mL. There was no overlap in the values of 95% confidence interval (CI) of higher control limit and lower asthmatic limit values. Addition of two standard deviations to the mean IgE value of the control group (134 IU/mL) does not overlap with the lower 95% CI of the asthmatic group. However, serum IgE was within normal values in 5.9% of asthmatic patients in our study population. There was an inverse correlation between serum IgE levels and forced expiratory volume in 1 second (FEV(1)) predicted percent for patients with asthma (r = -0.73, p < 0.0001). The predictive value of serum IgE in asthma was determined using Receiver Operating Characteristics (ROC) curve method. From the ROC curve, it can be seen that it is possible to get both high sensitivity and high specificity if the right cut-off value was chosen. In fact, a cut-off of 200 IU/mL would indicate sensitivity of 93% and specificity of 91% in this group of patients and control subjects. Following immunotherapy there was 36% reduction in total serum IgE level. The value of IgE was significantly reduced (p < 0.001) from 956 +/- 378 IU/mL at baseline to 613 +/- 194 IU/mL after treatment.

CONCLUSION

Serum IgE level was predictive in asthma, and it may be used to differentiate between asthmatic and non-asthmatic individuals in conjunction with other biomarkers. Specific immunotherapy reduced serum total IgE level in 36% of patients with asthma.

Expired breath condensate hydrogen peroxide concentration and pH for screening cough variant asthma among chronic cough

The reported studies suggest a role for eosinophils in the pathogenesis of cough variant asthma. In the present study, the expired breath condensate level of hydrogen peroxide and pH were determined in patients with cough variant asthma and compared to subjects with classical asthma, with chronic cough nonasthmatic and healthy control. Twenty-seven patients with cough variant asthma, 43 patients with classical asthma, 32 patients with chronic cough and 27 healthy subjects were studied in a cross-sectional study. Hydrogen peroxide concentration was significantly higher in cough variant asthma as compared to chronic cough nonasthmatic patients and healthy control subjects, while pH level was significantly lower in cough variant asthma as compared to chronic cough nonasthmatic patients and healthy control subjects. However, there was no significant difference in expired breath condensate hydrogen peroxide and pH between cough variant asthma and classical asthma. In conclusion, hydrogen peroxide concentration and pH of expired breath condensate may be used as noninvasive markers to differentiate cough variant asthma from chronic cough.