罗格列酮对变应性鼻炎小鼠galectin-9、tim-3信号和炎性分子表达的影响

目的研究PPAR-γ激动剂罗格列酮(ROS)对变应性鼻炎小鼠鼻黏膜半乳糖凝集素-9(galectin-9)和T细胞免疫球蛋白黏蛋白分子-3(tim-3)表达的影响。方法应用卵清蛋白(OVA)致敏建立小鼠变应性鼻炎模型,应用免疫组化及Real Time-PCR方法检测ROS对小鼠鼻黏膜中galectin-9和tim-3表达影响,应用ELISA法检测小鼠血清中IL-4、IL-5、IFN-γ含量。结果变应性鼻炎(AR)小鼠鼻黏膜中galectin-9和tim-3表达较正常对照组明显增高,罗格列酮及地塞米松治疗后galectin-9和tim-3的表达降低。与正常对照组比较,变应性鼻炎小鼠血清IL-4、IL-5含量明显升高,而IFN-γ含量明显减低;罗格列酮组和地塞米松组IL-4和IL-5含量较AR组降低,IFN-γ含量上调。结论罗格列酮抑制变应性鼻炎黏膜炎症反应,可能与降低鼻黏膜galectin-9和tim-3的表达相关。     

变应性鼻炎和哮喘患者血清IL-5、IL-15及IL-18的水平研究

目的探讨IL-5、IL-15和IL-18在变应性鼻炎、支气管哮喘、变应性鼻炎合并哮喘疾病中的作用。方法采用双抗体夹心ELISA测定法对33例支气管哮喘患者、35例变应性鼻炎患者、35例变应性鼻炎合并哮喘的患者及35例正常健康查体者血清中IL-5、IL-15和IL-18的水平进行检测。结果支气管哮喘、变应性鼻炎、变应性鼻炎合并哮喘的患者血清中IL-5、IL-15和IL-18水平较正常对照组升高（P〈0．01）,IL-5、IL-15,IL-18水平在变应性鼻炎合并哮喘组均高于鼻炎组与和哮喘组;鼻炎组IL-5水平高于哮喘组（P=0．003）,哮喘组IL-18水平高于鼻炎组（P=0．001）。结论IL-5、IL-15和IL-18参与了过敏性鼻炎和哮喘的发病过程;变应性鼻炎合并哮喘的炎症程度较高;哮喘和鼻炎因发病部位不同炎症反应也有不同。     

IL-23 在变应性鼻炎小鼠模型中的作用及机制的研究

目的:探讨IL-23 在变应性鼻炎小鼠模型中的作用及机制的研究。方法:应用卵清蛋白(OVA)致敏建立小鼠变应性鼻炎模型,给予抗IL-23p19 单克隆抗体干预,计量抗原激发后小鼠搔鼻数量。应用HE 染色方法检测IL-23 对小鼠鼻黏膜炎症影响,应用ELISA 法检测小鼠灌洗液中IL-4、IFN-β及IL-17A 含量。应用PCR 方法检测鼻黏膜中FOXP3 的含量。结果:治疗后抗IL-23p19 抗体组小鼠搔鼻症状相对于抗体对照组明显减轻(P<0.05),与PBS 组比较,OVA 组小鼠鼻黏膜炎症细胞浸润明显(P<0.01),鼻腔灌洗液中嗜酸性粒细胞数明显升高(P<0.05);抗IL-23p19 抗体治疗后,小鼠鼻黏膜炎症细胞浸润显著降低(P<0.05),鼻腔灌洗液中嗜酸性粒细胞数明显降低(P<0.05);抗IL-23p19 抗体治疗后,IL-4 及IL-17A 含量较IgG 抗体对照组降低(P<0.05),IFN-β含量不变(P>0.05)。抗IL-23p19 抗体治疗后,FOXP3 含量较IgG 抗体对照组增高(P<0.05)。结论:抗IL-23p19 抗体可有效治疗小鼠变应性鼻炎,其机制可能是抑制Th17 细胞的增殖并且促进调节性T 细胞的功能。     

PbGPI16在C57BL/6小鼠脑疟发病过程中作用的研究

目的：PbANKA原虫PbGPI16在小鼠实验性脑疟（ECM）发生和发展过程中的作用。方法：采用pbgpi16基因敲除的PbANKA原虫（△pbgpi16）和PbANKA原虫（WT）感染C57BL/6小鼠建立ECM模型。动态监测原虫血症和生存期;HE染色检测ECM小鼠脑组织炎性细胞浸润。qPCR观察感染后小鼠脑组织中CXCL9、CXCL10和CXCR3及脾细胞中TNF-α、IFN-γ和IL-1β转录水平。ELISA检测血清和脾细胞培养上清中TNF-α、IFN-γ和IL-1β表达水平。FACS检测感染后小鼠脾脏DCs细胞MHCⅡ和TLR4表达水平。结果：与WT组相比,△pbgpi16感染C57BL/6小鼠脑微血管壁损伤减轻,CXCL9、CXCL10、CXCR3、TNF-α、IFN-γ和IL-1β转录水平,小鼠血清和脾细胞培养上清中TNF-α、IFN-γ和IL-1β表达水平和脾DCs表达MHCⅡ及TLR4数量均显著下降（P<0.05）。结论：PbGPI16缺失通过减轻小鼠脑组织中趋化因子和脾脏中前炎症细胞因子转录水平,降低血清和脾细胞中前炎症细胞因子表达水平,降低DCs活化水平而抑制ECM发生。本研究旨在为疟疾感染后脑疟病理研究提供理论基础。     

实验变应性鼻炎模型小鼠构建以及与Th1/Th2失衡的相关性

背景：变应性鼻炎是指特应性个体接触变应原后,主要由IgE介导的介质组胺释放,并有多种免疫活性细胞和细胞因子等参与的鼻黏膜非感染性炎性疾病,与Th1和Th2免疫失衡相关。干扰素γ是Th1细胞分泌的细胞因子,而白细胞介素4是Th2细胞分泌的细胞因子。 目的：构建稳定的129Sv小鼠变应性鼻炎模型,为129Sv小鼠为背景来源的基因敲除小鼠构建实验变应性鼻炎模型奠定基础,观察IgE、白细胞介素4和干扰素γ浓度变化。 方法：将小鼠24只随机分2组,模型组采用卵清蛋白腹腔注射致敏激发,建立小鼠变应性鼻炎模型,对照组腹腔注射PBS。建模成功后用取小鼠鼻黏膜染色后评估鼻黏膜嗜酸性粒细胞、浆细胞浸润的病理变化。用ELISA法检测白细胞介素4和干扰素γ细胞因子水平和卵清蛋白特异性IgE抗体浓度。 结果与结论：与对照组相比,ELISA法检测显示,模型组血清中卵清蛋白-IgE和白细胞介素4浓度明显升高,干扰素γ浓度显著降低(P < 0.05);苏木精-伊红染色显示,模型组纤毛倒伏,黏膜下层浆液腺增生明显,嗜酸性粒细胞、浆细胞浸润较明显。结果证实,实验成功构建实验变应性鼻炎小鼠模型,变应性鼻炎的发病机制与Th1/Th2失衡有关。中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程     

克鼻敏汤剂对实验性变应性鼻炎大鼠细胞因子水平的调节作用

研究中药复方克鼻敏汤剂对实验性变应性鼻炎大鼠的治疗作用,并初步探讨其机制。用卵清蛋白致敏大鼠制作变应性鼻炎动物模型,并经灌胃克鼻敏进行预防性治疗。观察变应性鼻炎大鼠行为学改变;组织病理学方法观察鼻黏膜改变;采用ELISA法检测血清总IgE、卵清蛋白特异性IgE和细胞因子IFN-γ、IL-2、IL-4及IL-5水平。结果发现与模型对照组比较,克鼻敏治疗组行为学积分、血清总IgE和特异性IgE含量,IL-4和IL-5水平均明显下降(P<0.01);血清IL-2和IFN-γ明显升高(P<0.01)。克鼻敏治疗组与药物对照组和正常对照组比较,IFN-γ、IL-4和IL-5水平均无显著性差异,但克鼻敏治疗组行为学积分、血清总IgE和特异性IgE含量及IL-2水平均高于药物对照组和正常对照组。克鼻敏治疗组与强的松治疗组比较各项观测指标均无显著性差异。研究结果提示中药复方克鼻敏汤剂可通过调节细胞因子表达,下调IgE的产生达到对实验性变应性鼻炎的治疗目的。     

白介素17单克隆抗体对变应性鼻炎小鼠气道炎症的作用

目的 探讨白介素17单克隆抗体（IL-17mAb）的不同给予剂量及方式在变应性鼻炎小鼠气道炎症中的作用。方法 将48只小鼠采用随机数字表法分为A、 B、 C、 D、 E、 F组,每组8只。分别于第0、 7、 14 d将20 μg卵清蛋白（OVA）加2 mg铝佐剂腹腔注射处理A、C、D、E及F组小鼠,间隔7 d,第22天开始进行鼻腔激发,每天每侧鼻孔各给予OVA 10 μl（共500 μg）滴鼻,连续7 d。A、C、D、E组小鼠于每次OVA鼻腔激发前1 h分别给予生理盐水、100 ng IL-17mAb、500 ng IL-17mAb、5 μg IL-17mAb滴鼻,F组小鼠于每次OVA鼻腔激发前4 h给予5 μg IL-17mAb腹腔注射,B组小鼠于相同时间点给予等量生理盐水腹腔注射及滴鼻。所有小鼠于最后1次激发后评估鼻部症状学变化,Diff-Quik染色观察鼻腔灌洗液（NLF）中嗜酸性粒细胞浸润情况,ELISA方法检测血清及NLF中IL-6、IL-10水平,鼻黏膜组织行甲苯胺蓝染色观察肥大细胞。结果 ４周末A组所有小鼠症状学评分均＞5分,提示造模成功。F组小鼠的挠鼻及喷嚏次数均少于A组（P＜0.05）;F组小鼠NLF中嗜酸性粒细胞数、血清IL-6水平低于A组,血清及NLF中IL-10水平均高于A组（P＜0.05）;E组小鼠血清中IL-10水平高于A组（P＜0.05）;A组小鼠鼻黏膜组织中肥大细胞数多于B组,统计学意义显著（P＜0.01）;F组小鼠鼻黏膜组织中肥大细胞数少于A组,但差异无统计学意义（P＞0.05）;F组小鼠鼻黏膜组织中肥大细胞数与B组比较,差异无统计学意义（P＞0.05）。结论 高剂量的（5 μg）IL-17mAb腹腔注射处于激发阶段的变应性鼻炎小鼠促使小鼠变应性鼻炎症状明显减轻,鼻腔灌洗液嗜酸性粒细胞减少。促使变应性鼻炎小鼠血清中IL-6表达降低,血清中及鼻腔灌洗液中IL-10表达升高,因此推测这些细胞因子的变化可能抑制Th17/促进Treg的分化,进而对变态反应产生抑制作用。     

软叶针葵花粉疫苗治疗小鼠过敏性鼻炎的效果和机制

目的建立小鼠过敏性鼻炎模型,用重组软叶针葵花粉profilin疫苗免疫预防治疗,观察过敏性鼻炎小鼠的病理变化,探讨该疫苗对过敏性鼻炎治疗效果及可能机制。方法用腹腔注射法建立BALB/c小鼠软叶针葵花粉过敏性鼻炎模型,皮下注射过敏原疫苗进行预防治疗。通过小鼠无创肺功能仪检测小鼠治疗前后气道高反应性、间接ELISA检测血清中特异性抗体(IgE和IgG2a)、细胞因子,透射电镜观察鼻黏膜组织超微结构变化。结果疫苗特异性免疫治疗后,小鼠鼻部症状和气道高反应性减轻,其血清中特异性IgG2a水平升高、IgE水平降低,培养脾细胞上清中INF-γ、IL-10含量增加,IL-4生成减少。结论重组软叶针葵花粉profilin作为疫苗对花粉过敏性鼻炎有一定的疗效,可能与促使Th2向Th1转换,调节辅助性T细胞的平衡有关。     

IgE-FcεRI交联促进过敏性哮喘小鼠动脉粥样硬化的发生发展

 目的：观察过敏性哮喘加速小鼠动脉粥样硬化（AS）的发生和发展是否与Th2细胞及白细胞介素4（IL-4）有关,以及免疫球蛋白E（IgE）-Fc ε受体I（FcεRI）交联激活巨噬细胞途径在其中发挥的作用。方法：取6周龄的ApoE^-/-小鼠,以卵清蛋白致敏和激发建立过敏性哮喘模型,并分为对照组、哮喘安慰剂组和哮喘IL-4单克隆抗体干预组,分别干预8周,干预结束后处死小鼠,油红O染色检测主动脉根部斑块面积,流式细胞术检测脾脏Th2细胞比例,real-time PCR检测IL-4、IL-6、单核细胞趋化蛋白1（MCP1）和巨噬细胞炎症蛋白1α（MIP1α）的mRNA表达水平,ELISA法检测血清IL-4和IgE的含量。结果：与对照组相比,过敏性哮喘ApoE^-/-小鼠主动脉根部AS病变显著加重,并伴有体内Th2细胞和IL-4水平的增高,同时斑块处IgE和FcεRIα的表达显著增高,MCP-1、MIP-1α和IL-6的mRNA表达也显著增加;IL-4单克隆抗体干预8周后,主动脉根部AS病变缓解的同时,增高的IgE和FcεRIα表达被显著抑制,巨噬细胞相关炎性因子的表达水平也显著降低。结论：过敏性哮喘显著加速ApoE^-/-小鼠AS病变进展,此作用与体内Th2细胞和IL-4水平增加,以及IgE-FcεRI交联激活巨噬细胞途径有关。     

Clara细胞10 kD蛋白通过调控T细胞反应治疗小鼠变应性鼻炎研究北大核心CSCD

目的:探讨Clara细胞10 kD蛋白(CC10)对变应性鼻炎(AR)小鼠模型T细胞反应的作用。方法:卵清蛋白(OVA)免疫小鼠,建立AR模型,探讨CC10对AR的影响。最后1次鼻腔激发后评估小鼠鼻腔症状。收集鼻组织和鼻腔灌洗液(NLF),测定AR小鼠嗜酸性粒细胞、杯状细胞数及IL-5、IL-17、IL-10、TGF-β1、FOXP3水平。结果:激发期间给予CC10可显著减少AR小鼠搔鼻次数、嗜酸性粒细胞和杯状细胞数,降低IL-5、IL-17水平(P<0.05),但可增加IL-10、TGF-β1和FOXP3表达(P<0.05)。结论:CC10可通过调控T细胞反应减轻AR小鼠鼻腔炎症。     

IL-15 prevents allergic rhinitis through reactivation of antigen-specific CD8+ cells

BACKGROUND: Allergic rhinitis is one of the most common allergic inflammatory diseases characterized by a predominant TH2 response with antigen-specific IgE synthesis. IL-15 plays important roles in activation and maintenance of memory CD8+T cells capable of producing IFN-gamma, which regulates TH2 responses. OBJECTIVE: To investigate the roles of endogenous IL-15 in allergic inflammation, we examined allergic rhinitis in IL-15 knockout (KO) mice sensitized with ovalbumin followed by intranasal rechallenge with ovalbumin. METHODS: IL-15KO mice were sensitized intraperitoneally with ovalbumin/complete Freund's adjuvant on day 0 and ovalbumin/IFA on day 7, and then were intranasally challenged with ovalbumin on days 21, 22, 23, 24, and 25. Nasal symptoms and histologic changes were examined. IgE production and TH2 responses were measured by ELISA. Purified CD8+T cells or recombinant IL-15 were administered into ovalbumin-sensitized mice. RESULTS: The levels of IgE production and TH2 responses in IL-15KO mice were comparable to those in control mice after ovalbumin sensitization. However, sneezing, infiltration of eosinophils into the nasal mucosa, and TH2 cytokine production were aggravated in ovalbumin-sensitized IL-15KO mice after intranasal challenge with ovalbumin. Adoptive transfer of CD8+6 T cells from ovalbumin-sensitized mice suppressed the TH2 responses in mice but not in IL-15KO mice. Administration of IL-15 with ovalbumin significantly prevented the development of allergic rhinitis in ovalbumin-sensitized mice. CONCLUSION: We demonstrate with IL-15KO mice that endogenous IL-15 plays an important role in suppression of allergic rhinitis at effector phase. Intranasal administration of IL-15 is useful as a therapeutic approach to control allergic rhinitis. CLINICAL IMPLICATIONS: Intranasal administration of recombinant IL-15 might become new immunotherapy for allergic rhinitis.     

IL-13 is essential to the late-phase response in allergic rhinitis

BACKGROUND: The pathophysiology of the early- and late-phase nasal response to allergen challenge is not completely defined. Recent technical advances enable direct monitoring of these responses in mice. OBJECTIVE: IL-13 is detected in the nasal membranes of both human beings and mice with allergic rhinitis, but its role in disease pathogenesis is unclear. We measured early and late nasal allergic responses after treatment with soluble IL-13Ralpha2-IgG fusion protein (sIL-13Ralpha2-Fc), and in IL-13-deficient mice (IL-13(-/-)). METHODS: IL-13(-/-) mice (BALB/c background) and wild-type mice were sensitized to ovalbumin by intraperitoneal injection and then challenged intranasally with ovalbumin without sedation. The sIL-13Ralpha2-Fc or control human IgG was administered by intraperitoneal (i.p.) injection 24 hours and 1 hour before each ovalbumin challenge. Early nasal responses after the 4th ovalbumin challenge and late nasal responses 24 hours after the 6th ovalbumin challenge were assessed. RESULTS: Sensitized/challenged wild-type mice treated with sIL-13Ralpha2-Fc or IL-13(-/-) mice demonstrated significantly reduced late nasal responses in face of persistent nasal tissue eosinophilia; the early nasal response was little affected by targeting IL-13. Goblet cell hyperplasia was not detected in nasal membranes. CONCLUSION: The data indicate that IL-13 is a major contributor to the development of a late nasal response with little influence on the early response, and without affecting nasal eosinophilic inflammation. Inhibition of IL-13 may have an important therapeutic application in preventing the persistent nasal blockage in allergic rhinitis. CLINICAL IMPLICATIONS: Current therapies for allergic rhinitis may not take into account the important differences in the pathophysiology of the early and late responses and the important role of IL-13 in sustaining chronic nasal congestion and obstruction.     

特异性免疫治疗对哮喘小鼠的作用及机制的初步研究

目的　探讨特异性免疫治疗对哮喘小鼠的作用及其可能机制。方法　通过卵蛋白 (OVA)皮下注射的方法对致敏小鼠进行特异性免疫治疗 ,观察肺组织病理、支气管肺泡灌洗液 (BALF)细胞计数及分类、ELISA检测血清OVA特异性IgE(sIgE)及脾脏T淋巴细胞IL 2和IL 4的分泌 ,3H TdR掺入法检测T淋巴细胞的增殖反应 ,并与OVA致敏及激发的哮喘小鼠相比较。结果　哮喘特异性免疫治疗明显抑制小鼠肺组织炎症病理改变 ;BALF中细胞总数及嗜酸性粒细胞 (EOS)数显著减少 (P <0 .0 5 ) ;血清sIgE显著降低 (P <0 .0 5 ) ;T淋巴细胞IL 2和IL 4的分泌显著降低 (P <0 .0 5 ) ;T淋巴细胞对OVA的特异性刺激的反应显著降低 (P <0 .0 5 )。结论　特异性免疫治疗可显著抑制哮喘小鼠的炎症反应 ;诱导T淋巴细胞无能可能是特异性免疫治疗减轻哮喘相关炎症反应的机制之一     

Expression of interleukin-16 in allergic rhinitis

BACKGROUND: Interleukin-16 (IL-16) has been characterized as a chemoattractant for a variety of CD4+ T cells. Several inflammatory diseases, including allergic disorders, have been reported to correlate with IL-16. We first examined the IL-16 expression of serum and mucosal tissue in patients with allergic rhinitis. METHODS: Forty-eight patients with a clinical history of house dust mite (HDM) or pollen-sensitive allergic rhinitis were included in this study. Serum IL-16 was analyzed by enzyme-linked immunosorbent assay (ELISA). IL-16 expression of nasal mucosa was detected by immunohistochemistry. RESULTS: IL-16 levels were elevated in the serum of patients with allergic rhinitis compared with normal controls. In particular, serum IL-16 levels in HDM-sensitive patients were higher than those in pollen-sensitive patients. IL-16 was significantly correlated with eosinophils in the peripheral blood of allergic rhinitis patients. Histologically, IL-16 was expressed in infiltrated lymphocytes and nasal gland cells. CONCLUSIONS: Our data indicate that one of the sources of elevated serum IL-16 in allergic patients may be gland cells and lymphocytes in allergic nasal mucosa. This IL-16 cytokine may be strongly associated with the developmental mechanism of allergic rhinitis.     

Th17细胞在小鼠变应性鼻炎鼻黏膜中的表达及意义

目的：探讨T辅助细胞17(Th17)在小鼠变应性鼻炎鼻黏膜中的表达及意义。方法：以卵清蛋白致敏的Balb/c小鼠变应性鼻炎模型作为实验组,同期以生理盐水替代作为对照组。取两组小鼠鼻黏膜,制成单细胞悬液,使用流式细胞仪检测两组小鼠鼻黏膜中Th17细胞比例。结果：两组小鼠鼻黏膜中均存在Th17细胞,并且实验组中Th17比例[(1.27±0.138)%与(0.771±0.088)%]高于对照组,差异具有统计学意义(P<0.05)。结论：明确变应性鼻炎鼻黏膜中Th17细胞比例,为变应性鼻炎的治疗提供理论依据以及新思路。     

Topical CTLA4-Ig suppresses ongoing mucosal immune response in presensitized murine model of allergic rhinitis.

Allergic rhinitis is thought to be mediated by CD4+ T cells producing Th2-associated cytokines. Optimal Ag-specific T-cell activation requires the engagement of T-cell receptor with antigen (Ag) in the context of MHC, and the engagement of appropriate costimulatory molecules. One of the most well-characterized costimulatory pathways is the interaction of B7/CD28-CTLA4 molecules. Recent studies have suggested that the costimulatory pathway may influence the development of Th2 immune responses. The objective of this study was the examination of the role of B7/CD28-CTLA4 costimulatory pathway in the pathogenesis of ovalbumin (OVA)-induced immune response in presensitized murine model of allergic rhinitis. Systemically presensitized BALB/c mice significantly developed Ag-induced early phase nasal symptoms, nasal hyperresponsiveness to histamine, nasal eosinophilia, serum levels of OVA- specific IgE and Th2-associated cytokines following repeated topical Ag challenges. Topical administration of CTLA4-Ig during nasal challenges inhibited Ag-induced nasal symptoms and histamine hyperresponsiveness. We also found a significant reduction in nasal lavage eosinophilia and serum levels of OVA-specific IgE. Furthermore, CTLA4-Ig treatment significantly decreased interleukin (IL)-4 content in nasal tissue, while there was no significant change in IL-5 or IFN-gamma levels. These results suggest that B7/CD28-CTLA4 costimulatory pathway mediates the development of ongoing Th2 immune responses and plays a major role in regulating allergic disease, such as allergic rhinitis.     

Neonatal exposure with LPS and/or allergen prevents experimental allergic airways disease: development of tolerance using environmental antigens

BACKGROUND: Studies show that children in rural environments develop less asthma and allergic rhinitis than their urban counterparts. This may be a result, in part, of neonatal exposure to environmental antigens such as LPS and/or early exposure to allergens. OBJECTIVE: This study examined the effects of neonatal allergen and/or LPS exposure on subsequent immune responses to allergen. METHODS: Newborn mice were exposed to LPS and/or ovalbumin. At age 6 weeks, these animals were sensitized and challenged with ovalbumin, and airway inflammation, hyperresponsiveness, and cytokine expression were assessed. RESULTS: Animals exposed to LPS in the neonatal period developed T cells expressing CD25 and IL-10 on sensitization and challenge. They demonstrated abrogation of airway hyperresponsiveness and significant decreases in IL-13 from bronchoalveolar lavage fluid and in specific IgE. IL-4-expressing spleen cells were also significantly decreased. Mice exposed in the neonatal period to ovalbumin demonstrated airway hyporesponsiveness after subsequent ovalbumin sensitization and challenge and did not produce specific IgE. In contrast, these animals showed increases in IFN-gamma. Animals exposed to both LPS and ovalbumin developed a response characterized by IL-10 and IFN-gamma-expressing T cells. CONCLUSION: This suggests that mucosal antigen exposure in the neonatal period results in inhibition of allergic responses to environmental allergens. Early LPS exposure directs mucosal responses toward tolerance, whereas ovalbumin exposure follows the T(H)1-type response on subsequent sensitization. CLINICAL IMPLICATIONS: This study suggests that prevention of airways allergy may be best achieved by appropriate exposure of the airway mucosa early in life to environmental antigens.