Five per cent of asthmatics remain symptomatic despite high-dose treatment. The aim of the study was to investigate how often such difficult-to-treat asthma is due to intractable asthma, misdiagnosis, non-adherence with therapy, or psychiatric problems.Difficult asthma was defined as persistence of symptoms despite treatment at step 4 of British guidelines or requirement for long-term oral glucocorticoids (step 5). Onehundred patients with a respiratory physician diagnosis of asthma were investigated in a single tertiary respiratory unit in an open and descriptive study.Twelve of the patients studied did not have asthma and a further seven had additional diagnoses. Of the remainder, 55 had an asthma diagnosis confirmed by demonstration of reversible airflow narrowing or peak flow variability, whilst 20 did not. Noncompliance with prednisolone therapy was more frequent in the 55 with confirmed asthma (nine of 18 prescribed oral prednisolone at a dose of o15 mg?day -1 ) and was not detected in the "unconfirmed asthma" group. There were no other significant differences between these groups. A major psychiatric component was detected in 10 patients.Systematic evaluation of difficult asthma is useful as it can identify alternative or additional diagnoses, psychiatric illness or nonconcordance with therapy in a substantial proportion of cases (32% in the present series). Eur Respir J 2003; 22: 478-483.

We have tested the hypothesis that the beneficial effects of corticosteroids in asthma may result from reduction in the number of inflammatory cells infiltrating the bronchial mucosa with inhibition of cytokine gene expression. A randomized parallel group study was performed in 18 moderately severe asthmatic patients in whom an elective trial of corticosteroid treatment was indicated. Fiberoptic bronchoscopy was performed and bronchial biopsies taken from segmental carinae before and after 2 wk treatment with prednisolone (0.6 mg/kg/d) or matched placebo tablets. Immunohistology was performed on 6-microns cryostat sections using monoclonal antibodies. The number of cells expressing cytokine messenger RNA (mRNA) was assessed by in situ hybridization using S35-labeled riboprobes. When prednisolone- and placebo-treated groups were compared there was a decrease in airway methacholine responsiveness (p < 0.01) and an increase in FEV1 (p < 0.05) after prednisolone. This was accompanied by a reduction in CD3+ T lymphocytes (p < 0.05), "activated" EG2+ eosinophils (p < 0.02), and tryptase-only (mucosal-type) MCT cells (p < 0.02) but not MCTC (tryptase+chymase positive) cells in prednisolone-treated patients. In prednisolone-treated patients there was also a reduction in the number of cells expressing mRNA for interleukin-4 (IL-4, p < 0.01), and interleukin-5 (IL-5, p < 0.03) and an increase in cells expressing mRNA for interferon-gamma (IFN-gamma) (p < 0.01). These results support the view that corticosteroid treatment in asthma may act by modulation of cytokine expression with consequent inhibition of the local bronchial inflammatory infiltrate and tissue eosinophilia.

Immunohistology and in situ hybridization were used to evaluate the presence, activation status, and cytokine mRNA profile of cells in the bronchial mucosa during human allergen-induced asthma. Fifteen atopic asthmatic subjects underwent inhalation challenge with allergen and with allergen diluent, performed in random order separated by an interval of at least 3 wk. Bronchial biopsies were obtained 24 h after challenge. Immunostaining revealed increases in the numbers of secreting eosinophils (EG2+; P < 0.05) and in interleukin-2 receptor (IL-2R)-positive cells (CD25+; P < 0.01) after allergen compared with diluent challenge. No differences were observed in the numbers of total leukocytes (CD45+), T lymphocytes (CD3+, CD4+, and CD8+), elastase-positive neutrophils, macrophages (CD68+), or mast cell subtypes (MCT+ or MCTC+). In situ hybridization revealed significant increases in the numbers of cells expressing mRNA for IL-5 (P < 0.02) and granulocyte/macrophage colony-stimulating factor (P < 0.01) after allergen compared with diluent challenge. A significant inverse relationship was observed between the number of cells expressing mRNA for IL-4 and for interferon-gamma (r = -0.75, P < 0.02). The results support the view that cytokines possibly from activated T lymphocytes may contribute to local eosinophil accumulation during allergen-induced asthma.

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T-helper (Th) 2 cytokines are thought to mediate most features of allergic inflammation in atopic asthma. However, it remains unclear whether chemokine pathways direct selective recruitment of Th2 cells to the airways during human allergic responses.Bronchoalveolar lavage (BAL) was performed in 15 nonsmoking mild atopic asthmatics before and 24 h after a fibreoptic segmental allergen challenge, and chemokines related to T-cell recruitment were assayed by ELISA.The Th2-related C-C chemokine (CCR)4 ligands, macrophage-derived chemokine/C-C chemokine ligand (CCL)22 and thymus and activation-regulated chemokine/CCL17, were increased in BAL after challenge. These chemokines correlated significantly with lymphocyte numbers and with interleukin (IL)-5 and IL-13 in post-challenge BAL. In contrast, two out of three putative Th1-related chemokines did not change. There were no alterations in monokine induced by interferon (IFN)-c/CXC chemokine ligand (CXCL)9 or macrophage inflammatory protein-1a/CCL3; whereas a significant increase in IFN-induced protein-10kDa/CXCL10 was observed, which did not correlate with the T-cell influx. In peripheral mononuclear cells from atopic donors, CCL22 and CCL17 were induced by IL-4 and IL-13, further supporting the relationship between CCL22/CCL17 and Th2 cytokines. Finally, CCL22 was able to trigger actin polymerisation in peripheral CD4z T-cells expressing CCR4.Thus, C-C chemokine receptor 4 ligands are up-regulated in the airways of atopic asthmatics following allergen exposure, contribute to the T-cell influx to the airways and are closely related to the Th2-cytokine response.