Nasal tolerance with collagen v protein reverts bronchovascular axis remodeling in experimental bronchiolitis obliterans

INTRODUCTION: The precise role of the remodeling process and possible therapies for bronchiolitis obliterans remain to be established. OBJETIVE: In the present study, we sought to validate the importance of nasal collagen V tolerance to verify whether bronchovascular axis remodeling could be reverted by this therapeutic approach when compared to steroid treatment. METHODS: Mice were randomly divided into 4 groups: control, bronchiolitis obliterans, collagen V tolerance, and prednisone groups. Morphometry was employed to evaluate bronchovascular axis dimensions, collagen density, and immune cell response. Collagen V nasal tolerance and steroid-treated mice showed significantly lower values of terminal bronchiole wall thickness and reduction in peribronchovascular cells; bronchioalveolar lymphoid tissue; and CD3+, CD4+, CD8+, and CD20+ lymphocytes. A significant decrease in CD68+ macrophage density was found in prednisone-treated mice. In addition, a strong quantitative relationship was found between collagen V tolerance, and reduction in density of immune cells and collagen. RESULTS: Our results indicate that bronchovascular axis remodeling in bronchiolitis obliterans can be reverted by collagen V nasal tolerance, possibly as the result of T-cell suppression. CONCLUSION: We concluded that the tolerance effects in this model were strongly related to the improvement in bronchovascular remodeling, and these may be an appropriate targets for further prospective studies on nasal collagen V tolerance.

INTRODUÇÃO: A participação precisa do processo de remodelamento e possíveis implicações no tratamento da bronquiolite obliterante ainda não está estabelecida. OBJETIVOS: Estabelecer a importância da tolerância nasal induzida pelo colágeno do tipo V e verificar se o processo de remodelamento do eixo broncovascular pode ser revertido com esta estratégia terapêutica comparada ao efeito do tratamento com esteróides. MATERIAL E MÉTODO: Camundongos foram divididos em quatro grupos: controle, bronquiolite obliterante, tolerância nasal com colágeno do tipo V e prednisona. Morfometria foi realizada para avaliar as dimensões do eixo broncovascular, densidade de colágeno e resposta imunocelular. Camundongos submetidos à tolerância nasal com colágeno do tipo V e tratados com prednisona exibiram significativas reduções da espessura da parede de bronquíolos terminais, da densidade de células inflamatórias ao redor do eixo peribroncovascular e da resposta imunocelular às custas de linfócitos CD3, CD4, CD8 e CD20. Houve também significativa redução da densidade de macrófagos CD68 nos camundongos tratados com prednisona. Adicionalmente, houve uma forte associação entre tolerância nasal induzida pelo colágeno do tipo V, resposta imunocelular e redução do conteúdo de colágeno peribroncovascular. RESULTADOS: O remodelamento do eixo broncovascular na bronquiolite obliterante pode ser revertido pela indução de tolerância nasal com o colágeno do tipo V, possivelmente como resultado de supressão de linfócitos T. CONCLUSÃO: Os efeitos da tolerância nasal no presente modelo estiveram fortemente relacionados à melhora no remodelamento do eixo broncovascular, despontando como um alvo promissor para estudos prospectivos.

Nasal Eosinophilic Inflammation Contributes to Bronchial Hyperresponsiveness in Patients with Allergic Rhinitis

There are increasing evidences that allergic rhinitis (AR) may influence the clinical course of asthma. We conducted methacholine challenge test and nasal eosinophils on nasal smear to patients with allergic rhinitis in order to investigate the mechanism of connecting upper and lower airway inflammation in 35 patients with AR during exacerbation. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as thresholds of bronchial hyperresponsiveness (BHR). Thresholds of 25 mg/dL or less were assumed to indicate BHR. All patients had normal pulmonary function. Significant differences in BHR were detected in the comparison of patients with cough or postnasal drip and without cough or postnasal drip. There were significant differences of PC20 between patients with cough or postnasal drip and those without cough or postnasal drip (3.41 +/-3.59 mg/mL vs 10.2 +/-1.2 mg/mL, p=0.001). The levels of total IgE were higher in patients with seasonal AR than in patients with perennial AR with exacerbation (472.5 +/-132.5 IU/L vs. 389.0 +/-70.9 IU/L, p<0.05). Nasal eosinophils were closely related to log PC20 (r=-0.65, p<0.01). These findings demonstrated that nasal eosinophilic inflammation might contribute to BHR in patients with AR.

Increased levels of Circulating Autoantibodies to Cultured Human Bronchial Epithelial Cell in Adult Patients with Nonatopic Asthma

The pathogenetic mechanism of nonatopic asthma has not yet been defined. The idea of a possible involvement of autoimmunity in the pathogenesis of nonatopic asthma has been proposed by earlier studies. To evaluate the possible involvement of autoimmune response against bronchial epithelial cell in the pathogenesis of nonatopic asthma, we measured circulating autoantibodies to cultured human bronchial epithelial cell (BEAS-2B cell line) using enzyme-linked immunosorbent assay. We used stored serum samples form 38 age-matched healthy controls, 26 adult patients with atopic asthma, 16 adult patients with nonatopic asthma, and 12 adult patients with systemic lupus erythematosus. Levels of IgG autoantibodies to bronchial epithelial cell were significantly higher in patients with nonatopic asthma (mean+/-SD of absorbance values; 0.135+/-0.030) and systemic lupus erythematosus (0.293+/-0.181) than in healthy controls (0.112+/-0.016) and patients with atopic asthma (0.116+/-0.031) (p<0.05). This study showed that levels of circulating IgG autoantibodies to bronchial epithelial cell were increased in adult patients with nonatopic asthma. Further studies are needed to evaluate the possible involvement of autoimmune mechanism in the pathogenesis of nonatopic asthma.

Presence of circulating autoantibodies against bronchial epithelia cell in patients with nonatopic asthma

Allergic response to common environmental agents has been regarded as a main pathogenetic mechanism of bronchial asthma. However, allergic sensitization (atopy) can not be detected in a siginificant number of adult asthmatic patients. The etiology of nonatopic asthma has not yet been defined. To evaluate the possible involvement of autoimmune response against bronchial mucosa in the pathogenesis of nonatopic asthma, we performed indirect immunofluorescence staining of fresh frozen human bronchial mucosa tissue using serum samples from patients with atopic and nonatopic asthma, healthy controls, and patients with systemic lupus erythematosus. On immunostaining, circulating IgG autoantibodies against bronchial mucosa were detected in 2 (9.1%) of 22 patients with nonatopic asthma and in none of 22 patients with atopic asthma and of 22 healthy controls. IgG autoantibodies from the two patients with nonatopic asthma predominantly stained the cytoplasmic membrane of basal cells in bronchial epithelium. Serum samples from 10 patients with systemic lupus erythematosus immunostained the nucleus of epithelial cells in whole layer of bronchial epithelium. This study showed the presence of circulating IgG autoantibodies against the bronchial epithelial cell in a small portion of patients with nonatopic asthma. Further studies may be necessary to evaluate the possible involvement of autoimmune mechanism in the pathogenesis of nonatopic asthma.