Methotrexate therapy in asthma increases T cell susceptibility to corticosteroid inhibition

BACKGROUND: Concomitant methotrexate (MTX) therapy of severe, oral corticosteroid-dependent asthmatics has been shown to be corticosteroid sparing, but the mechanism is unknown. We hypothesized that MTX therapy of these patients increases the susceptibility of their T cells to corticosteroid inhibition. OBJECTIVE: To measure prednisolone inhibition of lectin-induced proliferation of peripheral blood T cells from a group of these patients before, during and following MTX therapy. METHODS: Eighteen severe asthmatics (median (range) age 56 (33-68) years, FEV1 61 (38-69)% predicted, dependent on oral prednisolone 15 (7.5-25) mg/day in addition to high-dose, inhaled corticosteroids) were treated with MTX 15 mg intramuscularly, weekly for 28 weeks. After 12 weeks of MTX, oral prednisolone dosages were reduced systematically over 16 weeks, provided that asthma control did not deteriorate. Patients were followed for a further 12 weeks after MTX withdrawal. Concentration-dependent, prednisolone inhibition of lectin-induced proliferation of peripheral blood T cells was measured just prior to MTX therapy (week 1) and at weeks 12, 28 and 40, and IC50 concentrations were interpolated. RESULTS: By week 28 of MTX therapy, patients were able to reduce oral prednisolone dosages from (median, SIQR) 15 (10-20.5) to 5.9 (1.4-9.4) mg/day (P<0.01) without alteration of lung function and symptoms, while median IC50 values for prednisolone inhibition of peripheral blood T cell proliferation were reduced from 49 (21-144) to 4 (1-9) nm (P<0.0001). These increased again to 15 (9.4-25.7) mg/day and 36 (18-67) nm, respectively, following MTX withdrawal. A correlation (P<0.01) was observed between percentage reductions in prednisolone dosages in vivo and fold changes in prednisolone IC50in vitro between weeks 12 and 28. CONCLUSION: This effect of MTX may at least partly account for its oral corticosteroid-sparing effect in severe asthma.     

Corticosteroid-resistant chronic asthma and monocyte complement receptors.

Monocyte complement receptors (MCR) and enhancement of MCR by a monocyte chemotactic factor (casein) (CRE) were measured in corticosteroid-resistant and corticosteroid-responsive chronic asthmatics. In newly-diagnosed patients who subsequently responded to corticosteroids, the percentage of MCR and CRE was lower after taking oral prednisolone for 7 days and returned to pretreatment values when prednisolone was withdrawn. MCR and CRE in corticosteroid-responsive asthmatics receiving prednisolone were significantly lower than in corticosteroid-resistant asthmatics taking prednisolone. However, there was no significant difference in MCR and CRE between non-responders taking prednisolone and non-responders receiving other forms of therapy. These results suggest that one of the effects of systemic corticosteroids in asthmatics who respond to this form of treatment is a decrease in both MCR and the degree of CRE. Since these changes were not found in corticosteroid-resistant chronic asthmatics such patients may have a defect in the expression and mobilization of complement receptors on the monocyte cell membrane.     

Methylprednisolone pulse therapy in acute severe asthma

Methylprednisolone pulse therapy (MPPT) has been shown to possess a long-lasting effect in other immune-inflammatory diseases without the well-known side effects caused by long-term treatment with glucocorticosteroids. In an attempt to reduce the long-term use of oral steroids in asthmatics, we conducted this double-blind, double-dummy study to compare the use of MPPT (1 g of methylprednisolone intravenously) (8 patients) with a short course of oral prednisolone (10 patients) in asthmatics presenting with acute severe asthma. Both treatments were effective in relieving the acute attack of asthma. The MPPT-treated patients did not show a faster resolution than did the orally treated group. No patients needed assisted ventilation, and no deaths occurred. One week after the treatment FEV1 tended to decrease in the methylprednisolone group compared with the oral prednisolone group (P = 0.06). The patients initially receiving MPPT needed supplementary prednisolone earlier and in higher doses than did the patients receiving oral prednisolone as initial treatment. At the end of the 12 weeks' study period, the groups reached identical FEV1. In conclusion, we did not find intravenous methylprednisolone superior to oral prednisolone in the treatment of acute attacks of severe asthma, but methylprednisolone pulse therapy had a shorter duration as regards protection against future asthma attacks.     

Corticosteroid resistance in mild asthma: markers of persistent inflammation.

BACKGROUND: Bronchial hyperresponsiveness (BHR) is an important feature of asthma. Glucocorticosteroids (GCS) reduce BHR, probably by suppressing allergic inflammation. There are, however, two groups of asthmatics with either GCS-responsive or non-responsive BHR to methacholine. We investigated the mechanism of non-GCS-responsive BHR in mild asthma. METHODS: Non-GCS-responsive BHR asthma was defined as failure of reduction of BHR to methacholine after a 2-week course of oral prednisolone (30 mg/day). The expression of interleukin (IL)-4, IL-5, IFN-gamma mRNA in peripheral blood mononuclear cells, eosinophil count, serum cortisol, eosinophilic cationic protein (ECP), and spirometry were measured in five non-GCS-responsive BHR asthmatics and six patients with GCS-responsive BHR asthma before and after prednisolone therapy. RESULTS: With the exception of serum ECP and expression of IL-5 mRNA, no significant differences were observed between GCS-responsive BHR and non-GCS-responsive BHR asthma. The mean ECP level was significantly higher in non-GCS-responsive BHR than in GCS-responsive BHR asthma before and after prednisolone therapy. Interleukin-5 mRNA was detected in all asthmatics before prednisolone therapy; however, after prednisolone therapy, IL-5 mRNA was only detected in non-GCS-responsive BHR asthmatics. CONCLUSIONS: Our findings suggest that activation of eosinophils appears to persist in some asthmatics with non-GCS-responsive BHR due to continuous IL-5 production by lymphocytes.     

Adrenocortical function during high-dose beclomethasone aerosol therapy

Prolonged observation of eight steroid-dependent asthmatics show that the dose of beclomethasone dipropionate aerosol may be increased in some cases up to 2000 μg daily without significant impairment in the results of serial tetracosactrin tests of adrenocortical function. These findings contrast sharply with the results of such tests during oral prednisolone therapy.     

IgE anti Hepatitis B virus surface antigen antibodies detected in serum from inner city asthmatic and non asthmatic children

Viral Hepatitis type B (HBV) is a public health concern, but has not been linked to asthma. Immunoglobulin (Ig) G is involved in HBV immune responses; less is known about IgE antibodies (Abs) against HBV in asthma. Given the importance of HBV, we sought to determine whether HBV vaccine contributes to asthma in children, by stimulating specific IgE production. Total IgE, IgE- or IgG-anti-HBVs Abs were studied in vaccinated pediatric asthmatics and non asthmatics. We found: (1) total IgE was higher in asthmatics; (2) total IgE did not correlate with IgE anti-HBVs; (3) IgE anti-HBVs did correlate with IgG-anti-HBVs in all subjects; (4)IgE- and IgG-HBVs Abs were similar in both groups; (5) IgE- or IgG anti-HBVs Abs did not correlate with age. Our findings indicate that HBV vaccination induces IgE responses in asthmatics and non asthmatics.     

Prednisolone disposition in steroid-dependent asthmatics

A 40-mg intravenous dose of prednisolone was given as prednisolone phosphate to seven severe steroid-dependent asthmatics and to 13 healthy volunteers to determine if the large prednisone requirements of these patients were a function of the disease, cellular response, or rapid clearance of prednisolone. Plasma concentrations of prednisolone, prednisone, and cortisol were determined by high-performance liquid chromatography over an 8-hr test period. Circulating eosinophil concentrations were monitored concurrently. The apparent half-lifes of prednisolone in the asthmatics and normals were 3.33 ± 0.71 and 3.25 ± 0.58 hr (mean ± SD). The apparent plasma clearances of prednisolone were 201 ± 54 and 198 ± 38 ml/min11.73 m² and the apparent volumes of distribution were 50.8 ± 11.7 and 53.5 ± 13.5 L/1.73 m² for the asthmatic and normal groups, respectively. When the concentration-dependent binding of prednisolone to plasma protein was examined, no differences in the apparent clearances of unbound drug were found between the two groups. The eosinopenic response to prednisolone was similar in the steroid-dependent asthmatics and healthy normal volunteers. These studies indicate that binding, distribution, and clearance of prednisolone are not responsible for the large prednisone requirement of some steroid-dependent asthmatics. Differences in steroid-receptor sensitivity or in severity or pathophysiology of the disease state more likely account for the need for large prednisone dosages in these patients.     

Bronchial inflammation in corticosteroid-sensitive and corticosteroid-resistant asthma at baseline and on oral corticosteroid treatment

BACKGROUND: Pathophysiology of corticosteroid (CS)-resistant asthma remains incompletely understood. OBJECTIVE: To determine if failure of asthma to clinically improve with CS is due to a defective response of airway bronchial inflammation to these drugs. METHODS: Twenty-one asthmatics having a decreased baseline FEV1 that improved >or= 30% with inhaled beta2 agonist got bronchial biopsies before and at the end of an oral CS treatment (methylprednisolone 40 mg daily for 14 days). They were arbitrarily divided into two groups according to baseline FEV1 improvement following this treatment: >or= 23% designated as CS-sensitive (CSS) (n = 10) and < 15% as CS-resistant (CSR) (n = 11). RESULTS: Before oral CS, counts of bronchial mucosa inflammatory cells identified by immunohistochemistry (CD3, MBP, tryptase, CD68, neutrophil elastase and CD25 for lymphocytes, eosinophils, mast cells, macrophages, neutrophils and IL-2 receptors, respectively) were similar in CSS and CSR subjects. Oral CS decreased CD3+ cell counts (medians: 60-20 cells/mm(2); P = 0.014) and MBP+ cell counts (medians: 19-4 cells/mm(2); P = 0.03) in CSS asthmatics, but only tryptase+ cell counts in CSR asthmatics (medians: 30-18 cells/mm(2); P = 0.05). Few bronchial neutrophil elastase+ cells were observed and their counts were similar in the two groups of asthmatics before and when on oral CS (all medians: = 2 cells/mm(2)). CONCLUSIONS: These data show that, in these subjects with moderate to severe asthma, lymphocytes and eosinophils constitute most of the inflammatory cells infiltrating the bronchial mucosa. They also demonstrated that clinical impaired response to CS is associated with a persistent bronchial mucosa cellular infiltrate despite oral CS treatment. Additional studies are required to determine the role of this CS-resistant bronchial inflammation in the impaired asthma clinical response to these drugs.     

Inhibitory activity of CX-659S,a novel diaminouracil derivative,against the rebound phenomenon following withdrawal of corticosteroid therapy for chronic contact hypersensitivity responses

BACKGROUND: CX-659S, a newly discovered anti-inflammatory compound, exerts inhibitory effects on chronic contact hypersensitivity responses (CHRs) induced by repeated application with picryl chloride (PC), which is known to mimic many, if not all, events occurring within lesional skin of patients with atopic dermatitis (AD). CX-659S suppresses the expression of mRNA for interleukin (IL)-4 and IL-10 but not that for IFN-gamma, and inhibits serum IgE production in a chronic CHR model. Although topical corticosteroids have been widely utilized in steroid-responsive dermatoses such as AD, their chronic use may be associated with significant side effects. In addition, a rebound phenomenon often occurs after discontinuation of prolonged use of topical corticosteroids, with enhanced production of IgE and Th2 cell cytokines. The purpose of this study was to assess whether CX- 659S inhibits the rebound phenomenon after discontinuation of chronic treatment with prednisolone in a chronic CHR model in mice. METHODS: The efficacy of CX-659S as a sequential therapeutic agent after discontinuation of chronic treatment with prednisolone was tested on PC-treated ears of BALB/c mice with chronic CHR. Effects were quantified by measurements of ear thickness, serum IgE and cytokine mRNA expression. RESULTS: The rebound phenomenon was confirmed after discontinuation of chronic treatment with prednisolone in chronic CHR in mice, i.e. by evidence of flare thickening of the ear, enhanced expression of mRNA for IL-4 and IL-10 and increased serum IgE. Sequentially applied CX-659S suppressed these rebound phenomena with a good cosmetic result. CONCLUSIONS: CX-659S is the first promising compound with inhibitory activity on the rebound phenomenon following withdrawal of corticosteroid therapy without immunosuppression.     

Immunological mechanisms of corticosteroid therapy in chronic active hepatitis: analysis of peripheral blood suppressor T-cell and interleukin 2 activities

To investigate the immunological mechanisms underlying corticosteroid therapy in chronic active hepatitis (CAH), in vitro effects of prednisolone on suppressor T-cell and interleukin 2 (IL-2) activities were examined in six corticosteroid therapy-effective and six therapy-ineffective patients with CAH prior to the therapy. Whereas low suppressor T-cell activity and decreased response to IL-2 in T cells were found in the corticosteroid therapy-effective group, these reductions recovered to the normal range when the activity or response was tested in the presence of prednisolone (1 and 10 micrograms/ml). Corresponding with these recoveries, suppressor T-cell activity arrived at normal values after corticosteroid therapy for 8 weeks. By contrast, in the corticosteroid-ineffective group, no apparent effects of prednisolone on suppressor T-cell activity and the response to IL-2 were observed. The relationship between the clinical effect of corticosteroid therapy and in vitro improvement in suppressor T-cell activity or in the response to IL-2 by prednisolone suggests that, in CAH, the corticosteroid effect is likely to be due to an immunomodulation in T-cell function.     

Hypogammaglobulinemia in steroid-dependent asthmatics correlates with the daily dose of oral prednisolone

BACKGROUND: Steroid-induced adverse effects including suppression of humoral immunity should be considered in steroid-dependent severe asthma. Only a few studies have determined the exact steroid dose that could potentially suppress humoral immunity in asthmatics. METHODS: Randomly selected 100 adult asthmatics treated with inhaled beclomethasone dipropionate (BDP) were classified into three groups based on the dose of steroid to determine the serum IgG, IgA and IgM levels by radioimmunoassay. Relationships between serum immunoglobulin levels and the daily dose and duration of oral prednisolone (PSL) therapy were examined. RESULTS: None of the patients on inhaled corticosteroid alone had hypogammaglobulinemia. Patients on oral PSL at a dose >12.5 mg/day for at least 1 year had low serum IgG. There was no significant correlation between the duration of oral PSL therapy and serum IgG. CONCLUSIONS: Oral PSL can potentially suppress humoral immunity in severe asthma. In asthmatics, hypogammaglobulinemia could develop in those on a daily dose of PSL >12.5 mg, but is independent of the duration of such treatment. No suppression of humoral immunity was noted on inhaled corticosteroid therapy alone, either at low or high dose.     

Sputum induction in corticosteroid-dependant asthmatics: risks and airway cellular profile

Sputum induction with nebulized hypertonic saline is increasingly being used to evaluate airway inflammation. We investigated the procedure-associated risk in 16 asthmatics that were still symptomatic despite on high doses of regular corticosteroid (CS) therapy (7 on daily inhaled CS > or = 800 microg budesonide or equivalent; 9 on additional daily oral CS) and their sputum cellular profile. For comparison, 12 mild stable asthmatics and 10 normal healthy subjects were included. All subjects inhaled 3%, 4% and 5% hypertonic saline sequentially via ultrasonic nebulizer as a means to induce sputum. Maximal percentage fall of Forced Expiratory Volume on One Second (FEV1) during sputum induction was significantly greater in CS-dependent asthmatics (median % [IQR]: 16.0 [11.0-32.3]) than in mild asthmatics (5.3 [4.2-10.8], p = 0.002] and in normal subjects (4.6 [3.4-6.4]), p = 0.0001). The maximal percentage FEV1 fall was inversely correlated with baseline FEV1 (Rs= -0.69; p < 0.0001). Compared to mild asthmatics, induced sputum from CS-dependant asthmatics had proportionately fewer eosinophils (2.2 [0.8-7.0] versus 23.3% [10.7-46.3], p = 0.003) and greater neutrophils (64.2 [43.9-81.2] versus 28.7 [19.0-42.6], p = 0.009). Sputum neutrophils showed a significant inverse correlation to FEV1 (Rs = -0.51, p = 0.01). We concluded that sputum induction using nebulized hypertonic saline should be performed with caution in CS-dependant asthmatics. The airway cellular profile observed suggests that the immunopathology underlying CS-dependant asthmatics may be different or a consequence of CS therapy.     

Eosinophil activation status and corticosteroid responsiveness in severe asthma

BACKGROUND: Since eosinophils are implicated in asthma pathogenesis, we investigated whether these cells were activated in severe asthma. METHODS: Twenty-six asthmatics with different clinical responses to oral corticosteroid (CS), i.e. sensitive [change in forced expiratory volume in 1 s (DeltaFEV(1)) >/= 25% after oral methylprednisolone, 40 mg daily, for 14 days, n = 7], resistant (DeltaFEV(1) /= 20 mg oral prednisone daily for acceptable asthma control, n = 10), were studied. RESULTS: Calcium ionophore-induced leukotriene (LT) C(4) release of purified blood eosinophils was similar in the three groups. Cell incubation with granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced ionophore-induced LTC(4) release, and this effect was higher in CS-sensitive (5-fold) than in CS-resistant subjects (1.7-fold) (p = 0.02). CS treatment decreased blood eosinophil counts in these two groups of subjects (p 相似文献   

Studies of HLA antigen frequencies, IgE levels, and specific allergic sensitivities in patients having ragweed hayfever, with and without asthma.

In order to study genetic and immunological features which might be important in the pathogenesis of asthma, forty-one ragweed allergic seasonal asthmatics were first matched with forty-one ragweed allergic nonasthmatics on the basis of similar total IgE levels. No significant differences were observed in their sensitivity to ragweed antigen E (measured by histamine release), or in their skin response to ragweed antigens E, Ra3 and Ra5. An increased frequency of HLA-B5 was observed in nonasthmatics as compared to asthmatics (P = 0-03). Although frequencies of HLA-A1 and B8 were also elevated in nonasthmatics and HLA-B40 in asthmatics, these differences were not significant. The forty-one asthmatic patients were than paired with forty-one nonasthmatics patients were then paired with forty-one nonasthmatics on the basis of leucocyte sensitivity to ragweed antigen E. Similar HLA differences were found which were non-significant. No significant difference in total IgE levels were found between the two groups. Whereas no differences in IgE synthesis or antigen sensitivity was found in the two populations, the frequency of HLA antigens needs further study in larger groups.     

Total and specific IgE (house dust mite and intestinal helminths) in asthmatics and controls from Gondar, Ethiopia

BACKGROUND: The role, if any, of parasitosis in the development of asthma remains incompletely understood; both 'protective' and 'predictive' associations have been reported. We report a study which examined immunoglobulin (Ig) E responses to two common helminths in asthmatics living in Ethiopia. OBJECTIVE: To compare the frequencies of specific IgE antibodies to Ascaris and Necator species and to Der p 1 among 84 adult asthmatics and a referent group of nonasthmatics. METHODS: A case-control analysis. RESULTS: Total IgE levels were not different between the two groups. The presence of specific IgE to Der p 1 was strongly associated with asthma (P = 0.001). Raised levels of Ascaris-(P = 0.010) and Necator- (P = 0.001) specific IgE antibodies were more common among referents; there were no associations between specific IgE production to Der p 1 and either of the two parasites. CONCLUSION: These findings confirm the association between Der p 1 sensitization and asthma among urban, adult Ethiopians. While they also indicate a negative relationship with two indicators of helminth infestation it appears that this is not mediated through the immunological response to common aeroallergens.     

Step-down and step-up therapy in moderate persistent asthma

BACKGROUND: A step-down therapy may be more beneficial for the management of asthma than a step-up therapy. METHODS: Eighty-two asthmatic patients with moderate persistent asthma were enrolled in the study and randomized into three groups. One group of patients received 400 microg/day of beclomethasone dipropionate (BDP) for 4 weeks and then 800 microg/day for another 4 weeks (step-up group). The other two groups of patients received 1,200 microg/day of BDP for 4 weeks with or without short-term oral steroid (prednisolone, 0.5 mg/day for 1 week) and then 800 microg/day for another 4 weeks (step-down group). Severe exacerbation of asthma, asthma symptoms, respiratory function and rescue use of inhaled beta(2)-agonists were monitored. If asthma was well controlled, the dose of BDP was decreased every 3 months and if asthma was exacerbated, the dose of BDP was increased until 8 months after the initial treatment. RESULTS: Twenty-two patients during the run-in period, 4 patients in the step-up group, 2 patients in the step-down group treated with a high dose of BDP and no patients in the step-down group with oral steroids during first 4 weeks dropped out because of severe exacerbation of asthma. Although asthma symptoms and respiratory function significantly improved 8 weeks after the therapy in all groups, more significant and prompt improvements of these parameters were observed in patients of the step-down group than in patients of the step-up group after the first 2 weeks of treatment. Furthermore, step-down therapy with short-term oral steroid resulted in the lowest maintenance doses of BDP at 8 months of the three groups. CONCLUSIONS: These results suggest that step-down therapy starting with a high dose of inhaled steroid and short-term oral steroid is more effective in gaining prompt control of asthma and reducing the severe exacerbation of asthma and the maintenance dose of inhaled steroids than a step-up therapy starting with a low dose of inhaled steroids in patients with moderate persistent asthma.     

IgE and IgG antibody responses to recombinant Alt a 1 as a marker of sensitization to Alternaria in asthma and atopic dermatitis

BACKGROUND: Sensitization to Alternaria alternata is a risk factor for the development of wheezing and asthma. Alt a 1 is the major Alternaria allergen causing sensitization in asthmatics. Some atopic dermatitis (AD) patients have very high immunoglobulin (Ig)E antibody (ab) to Alternaria as analysed by Pharmacia CAP, however, it is not clear whether these are specific responses or whether Alt a 1 is involved in disease symptoms. OBJECTIVE: The aim of this study was to analyse specific IgE and IgG ab responses to recombinant Alt a 1 in asthmatic and AD patients and to compare these results to IgE ab against Alternaria measured by CAP. METHODS: Sera from individuals who were IgE positive to Alternaria by CAP were obtained from 58 patients with asthma/rhinitis, 19 patients with AD, and 20 patients with cystic fibrosis (CF) who were included as specificity controls. IgE and IgG ab to recombinant Alt a 1 were measured by radioimmunoassay (RIA). RESULTS: Of 43 asthma/rhinitis patients having an Alternaria CAP score > 2, a high percentage (93%) had both IgE and IgG ab to Alt a 1, emphasizing its importance as a major allergen. Only, 47% of AD patients with CAP score greater than 2 had ab to Alt a 1, and their levels were low when compared to the asthmatics. For CF controls, 75% of these patients had no IgE ab to Alt a 1, and those which were positive to Alt a 1 by RIA were also positive by CAP. Overall, patients with a low CAP (1-2) had a low prevalence (20-30%) of IgE or IgG ab to Alt a 1. CONCLUSION: IgE and IgG ab to Alt a 1 in asthmatics are good markers for sensitization to Alternaria. Although AD patients gave high Alternaria CAP scores, they had low or undetectable levels of IgE to Alt a 1, suggesting that other Alternaria allergens may be important in AD or that the CAP results are non-specific. Recombinant allergens may provide more specific measures of sensitization to fungi.     

Blood cell concentration of methotrexate in long-term therapy of inflammatory rheumatic diseases

To verify the possibility of a concomitant therapy control in 31 patients (18 psoriatic arthritis [PA], 13 rheumatoid arthritis [RA]) the blood cell concentration of Methotrexate (MTX) was continuously measured over a period of 6 months. The determinations were carried out by using a RIA of the CIS Corp. At any time MTX was determined laboratory and clinical examinations were done and the P-III-P serum-level was measured by using a RIA of the Behringwerke. The cellular MTX showed to be statistically significantly elevated compared to baseline, whereas within ranges of total cumulative dosages only insignificant fluctuations could be noticed. Like in the treatment of Psoriasis a strict correlation between the weekly administered dose and the cellular MTX could be established, the total cumulative dose, however, had no influence on the cellular MTX-level. In the treatment of RA slightly higher weekly dosages were necessary, which caused significantly higher cellular MTX concentrations in RA patients. Some correlations between clinical as well as serological parameters of disease activity could be noticed, nevertheless they do not allow distinct interpretations. In both diseases a significant relationship between the cellular MTX-level and the P-III-P serum-level could be realized. A storage of MTX in blood cells, especially in erythrocytes, seems to be evident. To reach therapeutical benefit in RA slightly higher mean dosages may be necessary. A therapy monitoring by the means of continuous determinations of cellular MTX seems to be impossible. In contrast an approach to the early detection of liver fibrosis can be given by the correlation between cellular MTX and the P-III-P serum levels.     

Effects of allergen inhalation and oral glucocorticoid on serum soluble CTLA-4 in allergic asthmatics

BACKGROUND: The serum soluble cytotoxic T lymphocyte associated antigen-4 (sCTLA-4) concentration is significantly elevated in patients with asthma, and sCTLA-4 concentration correlate with the severity of asthma. The aim of the present study was to investigate effects of allergen inhalation and oral glucocorticoid on concentration of serum sCTLA-4 in patients with allergic asthma. METHODS: Allergen inhalation challenge was conducted in allergic asthmatics with isolated early asthma response and those with dual asthma response. In a randomized, double-blind, placebo-controlled, parallel group fashion, prednisolone or placebo was give orally once a day for 2 weeks. Venous blood samples were collected before and after allergen inhalation or prednisolone administration for obtaining sera. The serum sCTLA-4 concentrations were determined using enzyme-linked immunosorbent assay. RESULTS: The serum sCTLA-4 concentrations in the dual responder group increased from 29.0 (14.5-43.7) microg/l [median (25-75 percentiles)] before allergen inhalation to 44.0 (24.3-61.3) microg/l 24 h after allergen inhalation. In the isolated early responders, there were no significant increase in serum sCTLA-4 concentrations after allergen inhalation compared with baseline levels. There was a significant decrease in serum sCTLA-4 concentrations after 2 weeks of glucocorticoid therapy [22.0 (15.5-31.0) microg/l] compared with baseline values [37.0 (19.5-53.0) microg/l], whereas there was no significant difference in the placebo group. CONCLUSION: This study has demonstrated that serum sCTLA-4 concentrations increased after allergen inhalation in sensitized asthmatic subjects, and that serum sCTLA-4 concentrations were downregulated by prednisolone therapy.     

Subsensitivity of beta responses during therapy with a long-acting beta-2 preparation.

The question whether some tolerance or subsensitivity of various beta receptors develops during therapy with long-acting oral beta-2 agents has practical and theoretical importance. We applied a strong beta-2 stimulus (terbutaline, 5.0 mg orally) at weekly intervals for up to three weeks in 19 stable asthmatics and bronchitics while commencing 5.0 mg terbutaline three times daily. The evening dose was omitted before each morning challenge. Challenges were continued at one and two weeks off terbutaline in some patients to test return of beta function. Patients received no ephedrine for two weeks before the study but were allowed aminophylline or isoproterenol inhalations up to 18 and 4 hr before challenges, respectively. Pulmonary function, pulse, and blood pressure were monitored at 0, 60, 120, and 180 min, and metabolic parameters measured at 0 and 180 min. There was significant drug tolerance in the drop and minimum diastolic pressure reached, rise in lactate, cyclic AMP, and blood glucose, and drop in eosinophils. Peak FEV1 and V50 dropped slightly, but vital capacity and minimal airway resistance did not change significantly. During continuous therapy this slight bronchial subsensitivity is probably obscured by elevated baseline function. It might assume importance during periods of excessive inhaler use or abrupt drug withdrawal.