The development of airway hyperreactivity in T-bet-deficient mice requires CD1d-restricted NKT cells.

T-bet(-/-) mice have been shown to have a profound deficiency in the ability to generate invariant NKT (iNKT) cells in the periphery due to a halt in terminal maturation, but despite this deficiency, T-bet(-/-) mice develop spontaneous airway hyperreactivity (AHR) and airway inflammation. Because in some situations the development of AHR requires the presence of iNKT cells, we sought to more clearly understand how AHR develops in T-bet(-/-) mice by examining T-bet(-/-) mice in several distinct mouse models of asthma, including spontaneous, OVA-induced and alpha-galactosylceramide (alpha-GalCer)-induced AHR. Surprisingly, we found that administration of alpha-GalCer, which very specifically activates iNKT cells, greatly increased the AHR response in the T-bet(-/-) mice. Moreover, in T-bet(-/-) mice, spontaneous AHR as well as AHR induced with OVA or alpha-GalCer were all eliminated by blocking CD1d, the restricting element of iNKT cells, using an anti-CD1d-blocking mAb. Although the number of the iNKT cells in T-bet(-/-) mice was reduced compared with that in wild-type mice, the remaining iNKT cells produced primarily IL-4 and IL-13, and only minimal amounts of IFN-gamma. We conclude therefore that the AHR that develops in T-bet(-/-) mice is dependent on the presence of iNKT cells, and that whereas T-bet(-/-) have reduced numbers of iNKT cells, these are sufficient for the development of AHR.

Activation of nonclassical CD1d-restricted NK T cells induces airway hyperreactivity in beta 2-microglobulin-deficient mice.

Allergic asthma is characterized by Th2-driven eosinophilic airway inflammation and by a central feature called airway hyperreactivity (AHR), development of which requires the presence of classical type I invariant NK T (iNKT) cells. Allergen-induced AHR, however, develops in beta(2)-microglobulin (beta(2)m)(-/-) mice, which lack classical iNKT cells, suggesting that in some situations iNKT cells may be dispensable for the development of AHR. In contrast, our studies now suggest that a CD1d-restricted, NK1.1(+) noninvariant TCR NKT cell population is present in beta(2)m(-/-) mice and is responsible for the development of AHR but not for Th2 responses. Furthermore, treatment of beta(2)m(-/-) mice with anti-CD1d mAb or anti-NK1.1 mAb unexpectedly abolished allergen-induced AHR. The CD1-restricted NKT cells in these mice, which failed to respond to alpha-galactosylceramide and which therefore were not classical type I iNKT cells, appear to represent an NKT cell subset restricted by a beta(2)m-independent form of CD1d. These results indicate that, although classical type I iNKT cells are normally required for the development of AHR, under different circumstances other NKT cell subsets, including nonclassical NKT cells, may substitute for classical iNKT cells and induce AHR.

Inhibition of airway allergic disease by co-administration of flagellin with allergen.

Bacterial flagellin, which activates Toll-like receptor 5 and cytosolic pattern recognition receptor Ipaf, has a strong immunomodulatory activity. In the present study, we examined whether intranasal co-administration of flagellin with allergen could modulate established airway hyperresponsiveness and Th2 response using an ovalbumin (OVA)-sensitized mouse model. Balb/c mice sensitized with OVA were treated with OVA-flagellin (FlaB) mixture three times at 1-week intervals. Seven days after the final OVA-FlaB administration, the mice were challenged with OVA inhalation, and airway responses and OVA-specific immune responses were evaluated. The OVA-FlaB treatment significantly suppressed OVA-induced airway hyperresponsiveness, airway eosinophilic inflammation, and OVA-specific Th2 cytokine productions in splenocytes. These results indicate that flagellin co-administered with allergen can modulate airway inflammatory response through inhibition of Th2 responses, and flagellin can be considered as a component for allergen-specific immunotherapy.

The inverse association between the presence of antibody to hepatitis B surface antigen and atopy in young adults.

BACKGROUND: Some bacterial and viral infections may reduce the risk of atopy, and this is based on the concept of their ability to divert the immune system towards the Th1 responses. Most of the hepatitis B virus (HBV) infections occur in the developing countries and this is where atopic disorders are least prevalent. Th1 responses are important for the viral clearance of HBV and also for antibody production. The aim of the study is to investigate whether the presence of antibodies to the hepatitis B surface antigen (anti-HBs) is inversely associated with atopy in adults. METHODS: A random sample of 358 subjects, who were without hepatitis B surface antigen, was recruited; they were aged from 18 to 79 years (105 young adults aged <40 years and 253 older adults aged > 40 years). Determinations of the anti-HBs and skin prick tests using aeroallergens were performed. Those subjects with one or more positive skin reactions (a mean wheal diameter 23 mm) were considered atopic. RESULTS: The prevalence rate of atopy (p=0.035) or the sensitization to Dermatophagoides farinae (p=0.01) was significantly lower in the subjects with anti-HBs than in those subjects without anti-HBs for the young adults, but not for the older adults. The logistic regression analysis that was done on the young adults showed that the presence of anti-HBs was associated with a significantly lower risk of atopy (the odds ratio adjusted for confounding variables = 0.40 [95% CI 0.16-0.981, p=0.046) or with the sensitization to D. farinae (0.20 [0.06-0.65], p = 0.008). CONCLUSION: The presence of anti-HBs produced by a natural HBV infection or vaccination might be inversely associated with atopy in young adults.

Relationship between dendritic cells and activated eosinophils in induced sputum of asthmatics.

It has been suggested that dendritic cells (DCs) are critical antigen presenting cells for eosinophilic airway inflammation in a mouse model of asthma, and cysteinyl leukotrienes may play a role in DC trafficking in asthmatics. We investigated whether the number of DCs is increased in the induced sputum of both atopic and nonatopic asthmatics and is related to activated eosinophil count in the sputum. Sputum was induced by inhalation of hypertonic saline in 9 atopic and 12 nonatopic asthmatics and 10 nonatopic normal controls, and differential cell counts were performed. DCs and activated eosinophils were identified by immunocytochemistry with monoclonal antibodies (anti-CD1a and EG2, respectively). There were significantly higher percentages of eosinophils, EG2+ cells, and CD1a+ DC in the sputum of atopic and nonatopic asthmatics compared with normal controls, respectively. In asthmatics, the percentage of CD1a+ DC was significantly correlated with that of EG2+ cells (Rs=0.62, p=0.004). We demonstrated that the increased number of DCs was evident in the induced sputum of both atopic and nonatopic asthmatics, and the DC number was related to the activated eosinophil count, which suggests that DCs may contribute to the ongoing eosinophilic inflammation in asthmatic airways, and vice versa.

Sensitivity of the skin prick test and specificity of the serum-specific IgE test for airway responsiveness to house dust mites in asthma.

BACKGROUND: The concept that asthma diagnosis based on allergen-specific IgE levels in serum is more accurate than diagnosis based on skin test reactivity is controversial. OBJECTIVE: To determine the atopy parameter that correlates most closely with airway reactivity to house dust mites in asthma. METHODS: Forty-three asthma cases were examined retrospectively for data on Dermatophagoides farinae-specific bronchoprovocation, serum-specific IgE, and skin prick tests. RESULTS: The maximal decreases in FEV1 following bronchoprovocation were correlated significantly with both the IgE levels and skin test scores. The accuracies of the tests were highest at a cutoff value of class 4 or higher for the IgE and of 3+ or higher for the skin test. At the cutoff values, the accuracies of both tests were similar (70% vs. 70%). The sensitivity of the skin test (81%) was higher than that of the IgE test (67%), whereas the specificity of the IgE test (71%) was higher than that of the skin test (52%). The sensitivity of the skin test was 91% at 2+ or higher, and the specificity of the IgE test was 95% at class 6 or higher. CONCLUSION: These results suggest that both the specific IgE level and the skin test reactivity are useful parameters in the prediction of positive airway responses to house dust mites in asthma. However, the skin test is more sensitive, whereas the IgE test is more specific. Therefore, these tests can be used in a complementary fashion (i.e., the skin test for screening and the specific IgE test for confirmation of the relevant allergen).

Strain-dependent suppressive effects of BCG vaccination on asthmatic reactions in BALB/c mice.

BACKGROUND: The choice of BCG vaccine strain may play an important role in vaccination efficiency. OBJECTIVE: To investigate whether the suppressive effects of BCG on asthma depend on the strain of BCG. METHODS: Female BALB/c mice were injected intraperitoneally with 1 of 4 different strains of BCG (1 X 10(6) CFU): Pasteur F1173P2, Tokyo 172, Tice, and Connaught. Seven days later, the animals were sensitized by 2 injections of ovalbumin (20 microg) at 2-week intervals before being provoked with 1% ovalbumin aerosols on 3 successive days. Thereafter, the mice underwent a methacholine bronchial challenge and were killed to quantify the inflammatory cells and cytokines in bronchoalveolar lavage fluid and the supernatant of cultured splenocytes. RESULTS: The eosinophil proportion in the bronchoalveolar lavage fluid was significantly lower and the concentration of interferon-gamma and the interferon-gamma-interleukin 5 (IL-5) ratio in the supernatant of cultured splenocytes were significantly higher in each of the BCG-treated groups (n=10 per group) than in the asthma control group (n=15). However, the methacholine sensitivity (P < .05) and IL-5 concentration (P < .01) in the supernatant of cultured splenocytes were significantly lower only in the group treated with the Tokyo strain of BCG. There was a significant positive correlation between IL-5 and IL-10 concentrations (r = 0.79; P < .001). CONCLUSIONS: The 4 strains of BCG suppressed asthma to different degrees, but all strains induced a shift in the T(H)1/T(H)2 balance toward T(H)1 without increasing IL-10-related regulatory T-cell activity.

Airway hyperresponsiveness to hypertonic saline as a predictive index of exercise-induced bronchoconstriction.

BACKGROUND: Changes in airway mucosal osmolarity are an underlying mechanism of bronchoconstrictive responses to exercise and hypertonic saline (HS). The purpose of this study was to examine whether an osmotic challenge test using HS can predict exercise-induced bronchospasm (EIB) in asthma patients. METHODS: Thirty-six young male asthmatic patients underwent bronchial challenge tests based on 4.5% HS, exercise (> 24h later), and methacholine (MCh) at the Chonnam National University Hospital. The relationships between responses to HS and exercise, and between MCh and exercise were evaluated. RESULTS: The maximal fall in forced expiratory volume in one second following exercise was significantly higher in the HS-responders (n=19) than in the HS-nonresponders (n=17, 35.9 +/- 4.1% vs. 17.9 +/- 2.7%, p<0.001), and there was a significant correlation between the severity of EIB and HS-airway hyperresponsiveness (AHR). When compared with the MCh-AHR test in terms of predicting EIB, the HS-AHR test showed higher specificity (71.4% vs. 42.90%), but a lower sensitivity (58.6% vs. 89.7%) and negative predictive value (29.4% vs. 50.0%). At the moderate AHR cutoff value, the MCh-AHR test had a specificity that was comparable with and predictive values that were higher than those of the HS-AHR test. CONCLUSIONS: The HS-AHR test was more specific than the MCh-AHR test, but was less sensitive and had a poorer negative predictive value, which in combination preclude the use of the HS-AHR test as a screening tool for EIB. The MCh-AHR test had a cutoff value for moderate AHR that may be more useful for predicting EIB in asthmatic patients.

Effects of cytokine milieu secreted by BCG-treated dendritic cells on allergen-specific Th immune response.

Bacillus Calmette-Guerin (BCG) is reported to suppress Th2 response and asthmatic reaction. Dendritic cells (DCs), the major antigen-presenting cells, infections with BCG are known to result in inducing various cytokines. Thus, DCs are likely to play a role in the effects of BCG on asthma. This study aims at investigating that cytokine milieu secreted by BCG-treated DCs directly enhances allergen-specific Th1 response and/or suppresses Th2 response in allergic asthma. DCs and CD3+ T cells were generated from Dermatophagoides farinae-sensitive asthmatics. DCs were cultured with and without BCG and subjected to flow cytometric analysis. IL-12 and IL-10 were determined from the culture supernatants. Some DCs were cocultured with T cells in the presence of D. farinae extracts after adding the culture supernatants from BCG-treated DCs, and IL-5 and IFN-gamma were determined. BCG-treated DCs enhanced significantly the expressions of CD80, CD86, and CD40, and the productions of IL-12 and IL-10. Addition of culture supernatants from BCG-treated DCs up-regulated production of IFN-gamma by T cells stimulated by DCs and D. farinae extracts (p<0.05), but did not down-regulate production of IL-5 (p>0.05). The cytokine milieu secreted by BCG-treated DCs directly enhanced allergen-specific Th1 response, although did not suppress Th2 response.

Increased releasability of skin mast cells after exercise in patients with exercise-induced asthma.

The role of lung mast cells in exercise-induced asthma (EIA) is controversial. To investigate whether the skin mast cell releasability is increased after exercise in EIA, 49 young atopic men with or without asthma took part in a free-running test for 6 min and were given skin prick tests using morphine, a mast cell secretagogue, before and after the exercise. The mean diameters of the wheal induced by morphine in patients with EIA were not significantly different from those in patients without EIA before exercise, although the baseline lung function was significantly lower and the airway hyperresponsiveness, the peripheral blood eosinophil count, and the size of the wheal in response to Dermatophagoides pteronyssinus were significantly higher in patients with EIA. However, the differences of the morphine-induced wheal diameter between patients with EIA and those without EIA became significant at 120 min after exercise (p<0.05), while the responses to histamine were not significantly different. These results suggest that exercise increases the releasability of skin mast cells in EIA patients whose asthma/allergy are relatively severe.

Late local urticaria as a long-term sequela of allergen-specific immunotherapy.

Local reaction to allergen-specific immunotherapy (SIT) usually appears within 30 minutes, but cases with exercise-induced urticaria at the SIT site 2-3 weeks after the last allergen injection have been reported. A 28-year-old man was treated with house dust mite-SIT for 5 years, due to asthma when he was an 11-year-old boy. On a treadmill exercise test for 50 minutes, erythema, swelling, and pruritus occurred at the SIT site, which lasted for one hour. There was no evidence of complement activation, and the skin biopsy specimens showed no apparent difference between the lesion and normal sites in the distribution of inflammatory cells and in mast cell degranulation. However, the morphine, but not the histamine, skin test responses were increased after the exercise. There must be a remaining long-term sequela of the SIT, including an increased releasability of mast cells, even after more than 10 years.

Asthmatic airway inflammation is more closely related to airway hyperresponsiveness to hypertonic saline than to methacholine.

BACKGROUND: Airway hyperresponsiveness (AHR) to direct stimuli, such as methacholine (MCh), is observed not only in asthma but other diseases. AHR to indirect stimuli is suggested to be more specific for asthma. The purpose of this study was to determine whether asthmatic airway inflammation is more closely related to AHR to hypertonic saline (HS), an indirect stimulus, than to MCh. METHODS: Sixty-four consecutive adult patients with suspected asthma (45 asthma and 19 non-asthma) performed a combined bronchial challenge and sputum induction with 4.5% saline, and MCh challenge on the next day. RESULTS: Both HS-PD15 and MCh-PC20 were significantly lower in asthma patients than in non-asthma patients. However, the sensitivity/specificity for asthma was 48.9%/100%, respectively, in the HS test and 82.2%/84.2%, respectively, in the MCh test. There was a significant relationship between HS-PD15 and MCh-PC20 and only 52.9% of patients with MCh-PC20 < or = 4 mg/mL showed HS-AHR, but 4 patients with HS-AHR showed MCh-PC20 > 4 mg/mL. There were significant correlations between both HS-PD15 and MCh-PC20 and FEV1, or sputum eosinophils, but FEV1 was more closely related to MCh-PC20 (r = 0.478, p < 0.01) than to HS-PD15 (r = 0.278, p < 0.05), and sputum eosinophils were more closely related to HS-PD15 (r = -0.324, p < 0.01) than to MCh-PC20 (r = -0.317, p < 0.05). Moreover, the IL-5 level (r = 0.285, p < 0.05) and IFN-gamma/IL-5 ratio (r = 0.293, p < 0.05) in sputum were significantly related to HS-PD15, but not to MCh-PC20. CONCLUSION: HS-AHR may reflect allergic asthmatic airway inflammation more closely than MCh-AHR.

Oropharyngeal angioedema induced by inhaled histamine.

Inhaled histamine used to measure airway responsiveness produces some side effects more frequently than does methacholine. It is possible that the inhaled histamine induces the side effects in asthmatics with increased end organ responsiveness to histamine. A 56-yr-old woman with chronic idiopathic angioedema presented with asthma-like symptoms. Methacholine challenge test was performed, with a negative result. Five days later, histamine inhalation test was done. FEV1 fell by 37% after inhalation of histamine concentration of 8 mg/mL. Immediately thereafter, severe angioedema on face, lips, and oropharyngeal area, foreign body sensation at throat, and hoarseness occurred. To assess end organ responsiveness to histamine, skin prick tests with doubling concentrations of histamine (0.03-16 mg/mL) were carried out on the forearm of the patient and six age- and sex-matched asthmatic controls. The wheal areas were measured. The patient showed greater skin responses than the controls. Regression analysis showed that the intercept and slope were greater than cut-off levels determined from six controls. The patient showed an increased skin wheal response to histamine, indicating the enhanced end organ responsiveness to histamine, which is likely to contribute to the development of the oropharyngeal angioedema by inhaled histamine.

Relationship between nasal and bronchial responsiveness in perennial allergic rhinitic patients with asthma.

BACKGROUND: The nasal and bronchial mucosa present similarities and most patients with asthma also have rhinitis, suggesting the concept of 'one airway one disease'. Although many studies may suggest the relationship between nasal and bronchial responsiveness in patients with allergic rhinitis and asthma, few studies have been published which address this question directly. The aim of this study is to investigate whether the relationship between nonspecific nasal and bronchial responsiveness exists in perennial allergic rhinitic patients with asthma. METHODS: Fifty-one perennial allergic rhinitic patients with the definitive or suspected asthma underwent methacholine bronchial provocation tests and nasal histamine challenge tests. A slope of the absolute changes in nasal symptoms score/log concentrations of histamine was calculated by linear regression analysis. A ratio of the final absolute change in nasal symptoms score to the sum of all the doses of histamine given to the subject was also calculated. The degree of bronchial responsiveness to methacholine was categorized as positive bronchial hyperresponsiveness (BHR) if PC(20) (provocative concentration of methacholine resulting in 20% fall in FEV(1)) was <4 mg/ml, borderline BHR if PC(20) was >or=4 but 16 mg/ml. Another index of bronchial responsiveness (BRindex) was calculated as the log [(% decline in FEV(1)/log final methacholine concentration as mg/dl) + 10]. RESULTS: The geometric means of the slope (4.47 vs. 2.95, p < 0.05) and the ratio (1.68 vs. 0.54, p < 0.01) were higher in patients with positive BHR (n = 23) than in patients with negative BHR (n = 19), respectively. The geometric means of the slope (3.50) and the ratio (1.13) in patients with borderline BHR (n = 9) were between the two groups, respectively. In all patients, the log-slope (r = 0.48, p < 0.001) and the log-ratio (r = 0.51, p < 0.001) were correlated well with the BRindex, respectively. Even in allergic rhinitic patients with definitive asthma, the log-slope was correlated with the BRindex (r = 0.39, p < 0.05) or log-PC(20) (r = -0.36, p < 0.05). CONCLUSIONS: The nonspecific nasal responsiveness may be related to the nonspecific bronchial responsiveness in patients with allergic rhinitis and asthma, which may support the viewpoint that allergic rhinitis and asthma represent a continuum of inflammation involving one common airway.

Peak expiratory flow rate underestimates severity of airflow obstruction in acute asthma.

BACKGROUND: Several investigators have demonstrated a considerable disagreement between FEV1 and PEFR to assess the severity of airflow obstruction. The purpose of this study was to examine whether the discrepancy between the two measurements affects the assessment in the severity of acute asthma. METHODS: Thirty-five consecutive asthma patients measured both FEV1 and PEFR at 0, 1hr, 1, 3, 5, 7 days of an emergency room admission using a spirometer and a Ferraris PEFR meter. The degree of discrepancy between FEV1 and PEFR expressed as % predicted values was determined. RESULTS: When predictive equations that recommended by the instrument manufacturers were used. PEFR measured with the PEFR meter (f-PEFR) was significantly higher than FEV1 at all time points, with 16.1% mean difference and unacceptable wide limits of agreement (-20.0-52.3%). The classification in severity was significantly different between FEV1 and f-PEFR (p < 0.001). The discrepancy was inter-instrumental in large part because f-PEFR was 10.1% higher than spirometric PEFR. Different predictive equations altered the degree of the differences but could not completely correct it. CONCLUSION: These results indicate that f-PEFR values underestimate the severity of airflow obstruction in acute asthma despite using recommended predictive equations. Therefore, these confounding factors should be considered when the severity of airflow obstruction is assessed with PEFR.

Steroid-induced delirium in a patient with asthma: report of one case.

Systemic steroids are highly effective for patients with moderate-to-severe asthma exacerbations. Steroid-induced psychosis is known to be one of the adverse effects of steroid therapy, although infrequent. However, there is no reliable method of predicting steroid psychosis. We experienced the case of a 40-year-old asthmatic man who had previously taken steroids without any psychological side effect, but became acutely delirious after receiving some doses of steroids, higher than the previous doses, under a condition of emotional stress. The mean dose of prednisolone administered was 82 mg/day (1.37 mg/kg/day) for 10 days but the patient had taken two courses of steroids (0.82 mg/kg/day and 0.5 mg/kg/day, respectively) for asthma exacerbations without any psychiatric episodes during the previous year. At this time, the patient was under a condition of emotional stress related to family reasons. The asthmatic exacerbation of this case may be precipitated from sudden emotional stress and the following treatment with a high dose of steroida should be used cautiously due to the possibility of psychotic side reactions.

Lactic acidosis associated with the usual theophylline dose in a patient with asthma.

Metabolic and electrolyte abnormalities, including hypokalemia, hyperglycemia and lactic acidosis, are associated with theophylline overdose. However, we report an unusual case of sinus tachycardia, lactic acidosis, hypokalemia and hyperglycemia associated with the usual theophylline dose in a patient with asthma. The theophylline dose was 200 mg orally twice daily. Three hours after administration of the third dose, the patient experienced palpitation. An electrocardiogram showed a sinus tachycardia. Arterial blood gas analysis revealed a mixed metabolic acidosis and respiratory alkalosis. Serum lactate level was 51 mmol/L (normal 0.7-2.1 mmol/L). Biochemistry results were sodium 136 mEq/L, chloride 99 mEq/L, potassium 1.9 mEq/L and glucose 204 mg/dL. Our case suggests that a possibility of theophylline-associated metabolic abnormalities should be considered when an asthmatic patient given the usual theophylline dose presents with lactic acidosis, hypokalemia and hyperglycemia of unknown etiology.

Therapeutic effects of BCG vaccination in adult asthmatic patients: a randomized, controlled trial.

BACKGROUND: Bacille Calmette-Guérin (BCG) vaccination in humans induces Th1 immune responses. Th1 and Th2 cells are reciprocally regulated. OBJECTIVE: To examine whether BCG vaccination of adult patients with asthma, a Th2-associated allergic disease, is clinically effective. METHODS: Forty-three moderate-to-severe asthma patients were randomly assigned into groups that received percutaneous injection of 58.2 x 10(7) CFUs BCG (n = 22) or placebo (n = 21) in a double-blinded fashion, on the first day of a 12-week treatment period. Medications were adjusted every 4 weeks to maintain optimal asthma control. Spirometric measurements were performed before treatment and at weeks 4, 8, and 12 after vaccination. The daily peak expiratory flow rate values, asthma symptoms, and medications were also recorded. Tuberculin skin tests, and sputum inflammatory cell and cytokine analyses were carried out before treatment and 12 weeks after vaccination. RESULTS: BCG vaccination significantly increased forced expiratory volume in 1 second and forced expiratory flow rate 25% to 75% at weeks 4, 8, and 12. Morning peak expiratory flow rate was significantly increased only during the first 4 weeks. Although the asthma symptom scores were not significantly changed, the weekly medication scores were significantly decreased. Tuberculin skin reactivities were significantly increased without significant alterations in induced sputum profiles. In contrast, medication scores and sputum eosinophils were significantly increased, and the interferon-gamma:interleukin-4 ratio in sputum was significantly decreased in the placebo group. CONCLUSIONS: BCG vaccination improved lung function and reduced medication use in adults with moderate-to-severe asthma. This amelioration was accompanied by a suppressed Th2-type immune response, suggesting that BCG vaccination might be an effective therapeutic modality against asthma.