Horohov D W, Beadle R E, Mouch S, Pourciau S S
Department of Veterinary Science, Maxwell Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546-0099, USA.
Vet Immunol Immunopathol. 2005 Oct 18;108(1-2):237-45. doi: 10.1016/j.vetimm.2005.07.013.
Acute and chronic inflammation of the airway remains an important health problem for equids. "Heaves" or recurrent airway obstruction (RAO) remains one of the most commonly diagnosed conditions affecting the lung of older horses in Europe and the United States. The typical clinical signs of RAO include non-productive coughing, serous nasal discharge, labored expiratory effort, and flaring of the nostrils. Auscultation of the lungs of the affected horse often reveals abnormal respiratory sounds, described as crackles and wheezes, throughout the area of the lung field. These clinical signs occur secondary to an inflammatory response that results in bronchospasm, excessive mucus production and airway obstruction. This inflammatory response is characterized by the presence of excessive mucus and inflammatory cells, primarily neutrophils, in the small airways. Most evidence suggests that RAO is the result of a pulmonary hypersensitivity to inhaled antigens. Exposure of affected horses to hay dust, pollens, and mold spores leads to neutrophil accumulation in the lung and bronchospasm. The identification of allergen-specific IgE in bronchoalveolar lavage (BAL) fluid and sera of affected horses supports the involvement of a late phase, IgE-mediated, hypersensitivity reaction in the pathogenesis of equine RAO. The production of IgE antibodies is regulated by the cytokines IL-4 and IL-13. Using a quantitative PCR method we have reported that horses with RAO exhibit a modified Type 2 cytokine response characterized by the production of IL-4 and IL-13 mRNA, but not IL-5 mRNA in BAL cells. Interferon-gamma mRNA was also elevated, suggesting a mixed response. While these results are consistent with equine RAO being the result of an aberrant Type 2 cytokine response to inhaled allergens, others have failed to find any evidence of elevated Type 2 cytokine mRNA in BAL from horses with "heaves". It is likely that these disparate results could be the result of differences in the clinical stage of the affected animals or the timing of sample collection. Here, we report a diverse pattern of cytokine gene expression when sampling a group of affected horses over a period of time.
气道的急慢性炎症仍然是马属动物面临的一个重要健康问题。“慢性阻塞性肺病”或复发性气道阻塞（RAO）仍是欧美地区影响老龄马匹肺部的最常见诊断疾病之一。RAO的典型临床症状包括干咳、浆液性鼻液、呼气费力以及鼻翼扇动。对患病马匹肺部进行听诊时，往往会在整个肺野区域发现异常呼吸音，表现为啰音和哮鸣音。这些临床症状是由炎症反应继发而来，炎症反应会导致支气管痉挛、黏液分泌过多和气道阻塞。这种炎症反应的特征是小气道中存在过多黏液和炎症细胞，主要是中性粒细胞。大多数证据表明，RAO是肺部对吸入抗原过敏的结果。患病马匹接触干草粉尘、花粉和霉菌孢子会导致中性粒细胞在肺部积聚和支气管痉挛。在患病马匹的支气管肺泡灌洗（BAL）液和血清中检测到过敏原特异性IgE，这支持了迟发性、IgE介导的过敏反应参与马属动物RAO发病机制。IgE抗体的产生受细胞因子IL-4和IL-13调节。我们使用定量PCR方法报告称，患有RAO的马匹表现出一种改变的2型细胞因子反应，其特征是BAL细胞中产生IL-4和IL-13 mRNA，但不产生IL-5 mRNA。干扰素-γ mRNA也有所升高，表明存在混合反应。虽然这些结果与马属动物RAO是对吸入过敏原异常的2型细胞因子反应的结果一致，但其他人未能在患有“慢性阻塞性肺病”的马匹的BAL中找到2型细胞因子mRNA升高的任何证据。这些不同的结果很可能是由于患病动物临床阶段的差异或样本采集时间的不同。在此，我们报告了在一段时间内对一组患病马匹进行采样时细胞因子基因表达的不同模式。
