屋尘螨特异性免疫治疗的哮喘患儿对尘螨过敏原免疫反应的变化

目的观察经屋尘螨特异性免疫治疗(SIT)的哮喘患儿对尘螨过敏原特异性免疫反应的变化。方法选取54例尘螨过敏性哮喘患儿,其中男性38例,女性16例;年龄6~11岁,平均年龄9岁1个月。27例经标准化屋尘螨过敏原皮下SIT疗程1.5~2.0年患儿作为SIT组,另27例未经SIT患儿作为对照组。应用最大呼气流量-容积曲线测定方法测定肺通气功能,参数为第1秒用力呼气容积(FEV1)占预计值百分比(FEV1%);应用荧光酶联免疫法测定2组患儿血清屋尘螨特异性IgE和特异性IgG4浓度;分离患儿外周血单个核细胞(PBMC),经质量浓度20μg/mL屋尘螨蛋白浸液刺激并培养48 h后,检测CD4+CD25+Foxp3+调节性T淋巴细胞(Treg细胞)的相对数量和可分泌白细胞介素10(IL-10)的Treg细胞百分比;同时留取细胞培养上清液应用酶联免疫吸附分析检测细胞因子IL-4、干扰素-γ(IFN-γ)和转化生长因子β1(TGF-β1)水平。结果 SIT组患儿肺功能FEV1%与对照组相比,差异无统计学意义(P>0.05);SIT组IgG4水平显著高于对照组,差异有极显著统计学意义(P<0.000 1)。SIT组IgE水平与对照组相比,差异无统计学意义(P>0.05);两组刺激后Treg细胞百分数分别与各自该组内未经刺激时基础水平的差异无统计学意义。两组间PBMC无论是否经屋尘螨蛋白浸液刺激时Treg细胞百分数的差异无统计学意义(P>0.05);SIT组刺激后Treg细胞百分数高于自身未经刺激基础水平1.56倍。对照组经刺激后与未接受刺激比较,Treg细胞百分数无显著变化;SIT组PBMC培养上清液中IL-4和TGF-β1浓度显著低于对照组,IFN-γ浓度显著高于对照组,差异有统计学意义(P<0.05)。结论屋尘螨SIT的哮喘患儿对尘螨过敏原特异性免疫反应表现为Treg细胞比率增加,Th1/Th2免疫反应平衡改变,屋尘螨特异性IgG4浓度增高,提示发生对尘螨过敏原特异性免疫耐受的特征。     

MK-8237: a house dust mite vaccine for treating allergic rhinitis,asthma and atopic dermatitis

ABSTRACT

Introduction: Since its introduction in clinical practice one century ago for the treatment of respiratory allergic diseases, allergen-specific immunotherapy (AIT) has exhibited a relevant clinical efficacy that was subsequently confirmed in controlled trials. Thus, AIT has been accepted worldwide, as testified by guidelines and international documents. AIT is considered pivotal in the management of allergic rhinitis with or without conjunctivitis and with or without asthma. These conditions, in addition to hymenoptera venom allergy, currently are the accepted indications. The use of AIT in house-dust mite allergy still remains debated, especially due to the methodological problems in assessing this form of respiratory allergy. The more recent experimental data on MK-8237 sublingual tablets provided evidence that AIT, in the sublingual form, is effective in dust mite allergy.

Areas covered: At present, the evidence of the efficacy of AIT in conditions other than respiratory allergy are not conclusive, but encouraging results have been obtained in food allergy and atopic dermatitis. Herein, the authors discuss the data for these indications.

Expert opinion: Not all patients respond to AIT in the same way. Accordingly, AIT represents a promising path to precision medicine and hopefully will be able to reduce this burden of non-responding patients.     

CpGODN对尘螨哮喘小鼠Foxp3表达的影响

目的研究CpG寡脱氧核苷酸(CpGODN)对尘螨哮喘小鼠Th1/Th2型细胞因子及肺组织中Foxp3蛋白表达的影响。方法用雌性C57BL/6J小鼠建立尘螨哮喘小鼠模型,在抗原致敏阶段加入CpGODN进行干预,并设立GpCODN治疗对照组及布地奈德治疗对照组,观察支气管肺泡灌洗液(BALF)中细胞总数、嗜酸性粒细胞百分比(EOS%)的变化;用酶联免疫吸附(ELISA)法检测BALF中IL-4、IL-5、IFN-γ的含量变化;用免疫印迹(Western-blot)法检测肺组织Foxp3蛋白的表达水平。结果与哮喘模型组及GpCODN治疗对照组比较,CpGODN治疗组的BALF中IL-4、IL-5的浓度降低,IFN-γ浓度升高,肺组织中Foxp3蛋白表达增高;相关性分析显示肺组织Foxp3表达与BALF中IFN-γ水平呈正相关,与BALF中IL-4、IL-5水平、EOS绝对值均呈负相关。结论 CpGODN能够改善尘螨哮喘小鼠气道炎症,调节Th1/Th2型细胞因子的平衡,可能是通过诱导Foxp3的表达来起到免疫调节的作用。     

Skin tests, T cell responses and self-reported symptoms in children with allergic rhinitis and asthma due to house dust mite allergy

Background In allergic responses, a distinction is made between an early-phase response, several minutes after allergen exposure, and a late-phase response after several hours. During the late phase, eosinophils and T cells infiltrate the mucosa and play an important role in inflammation. Objective The aim of this study was to examine the relationship between allergen-induced late-phase skin responses and in vitro T cell reactivity. In addition, the relationship between allergen-induced skin or T cell responses and the severity of self-reported symptoms was studied in children with house dust mite allergy. Methods A total of 59 house dust mite-allergic children (6–18 years) were recruited in general practice. These children or their parents rated their nasal and asthma symptoms on diary cards during 1 month. Allergen skin tests were performed and read after 15 min (early phase) and 6 h (late phase). Allergen-specific T cell proliferation was determined, and Th2 cytokine (IL-5 and IL-13) secretion was analysed. Results The size of the late-phase skin response correlated with in vitro T cell proliferation (r_s=0.38, P=0.003) but not with Th2 cytokine secretion (r_s=0.16, P=0.2 for both IL-5 and IL-13). Moreover, the late-phase skin response and T cell proliferation correlated with asthma symptoms (r_s=0.30, P=0.02 for skin response and r_s=0.28, P=0.03 for T cell proliferation) but not with nasal symptoms (r_s=0.19, P=0.15 for skin response and r_s=0.09, P=0.52 for T cell proliferation). The early-phase skin response correlated with the nasal symptom score (r_s=0.34, P=0.01) but not with asthma symptom scores (r_s<0.005, P=0.97). Conclusion In this study, the late-phase skin test response correlated with in vitro T cell proliferation but not with Th2 cytokine secretion. We found weak or no correlations between late-phase skin responses and symptoms of asthma or rhinitis in children with house dust mite allergy. This suggests that late-phase skin responses reflect certain T cell properties but are of limited value for the evaluation of airway symptoms in atopic children.     

Engineering of major house dust mite allergens Der p 1 and Der p 2 for allergen-specific immunotherapy

Background Specifically designed recombinant allergens with reduced IgE reactivity are promising candidates for a more defined, effective, and safer specific immunotherapy (SIT).
Objective We sought to obtain hypoallergenic hybrid molecules which could potentially be applied to house dust mite (HDM) allergy treatment.
Methods Two hybrid molecules (QM1 and QM2) derived from the two major Dermatophagoides pteronyssinus allergens, Der p 1 and Der p 2, were engineered by PCR, produced in Escherichia coli , and purified. The overall IgE-binding capacity of the hybrids was compared with their single components by Western blot, specific IgE, skin prick test (SPT), and IgE-inhibition assays. T cell proliferation assay were performed to confirm their retention of T cell reactivity. Immune responses to the hybrid molecules were studied in BALB/c mice.
Results The IgE reactivity of both hybrid proteins was strongly reduced as evaluated by in vitro methods. Furthermore, in vivo SPTs performed on 106 HDM-allergic patients showed that the hybrid proteins had a significantly lower potency to induce cutaneous reactions than the individual components. Hybrid molecules induced higher T cell proliferation responses than those produced by an equimolecular mixture of Der p 1 and Der p 2. Immunization of mice with the hybrid proteins induced Der p 1- and Der p 2-specific IgG, which inhibited the binding of allergic patients' IgE to these natural allergens.
Conclusion QM1 and QM2 hybrids exhibited less IgE-binding activity but preserved immunogenicity and fulfilled the basic requirements for hypoallergenic molecules suitable for a future SIT of HDM allergy.     

Sublingual immunotherapy efficacy in patients with atopic dermatitis and house dust mites sensitivity: a prospective pilot study

ABSTRACT

Background: Specific subcutaneous immunotherapy (SCIT) with house dust mite (HDM) preparation has recently been shown to improve eczema in patients with atopic dermatitis (AD). So far, there is less data regarding efficacy and safety of specific sublingual immunotherapy (SLIT) in patients with AD.

Study aim: To evaluate in an open non-controlled, non-randomized pilot trial the effect of SLIT with HDM allergen extracts preparation (SLITone, ALK Abellò Italy) on SCORAD in adult patients with mild–moderate AD.

Patients and methods: 86 Subjects (53 females and 33 males) between 3 and 60 years of age with AD and IgE-proved (Class > 2) HDM sensitization were enrolled after their informed consent in the trial. Exclusion criteria were severe asthma and treatment with systemic or high potent topical corticosteroids or immunosuppressant agents. Patients were treated with SLIT (Dermatophagoides pteronyssinus and Dermatophagoides farinae extracts: SLITone, ALK-Abellò) for at least 12 months. SCORAD was evaluated at baseline and after 12 months of treatment.

Results: Baseline SCORAD value, mean ± SD, was 43.3 ± 13.7 (range 15–84). After 1 year of SLIT, mean ± SD, SCORAD value was reduced to 23.7 ± 13.3 (range: 0–65) (p = 0.0001; unpaired t-test vs. baseline). This was a 46% reduction in SCORAD in comparison with baseline value. A significant improvement, defined as a SCORAD reduction of > 30%, was observed in 51 out of 86 patients (59%). In 5 patients (5.8%) SCORAD values did not change at the end of the observation period. In 30 patients (35%) the SCORAD reduction after SIT was ≤ 30% in comparison with baseline. Total and specific IgE serum levels were significantly (p = 0.001) reduced after SLIT. No severe adverse events were observed during the trial.

Conclusion: In this open non-controlled trial SLIT with HDM extracts in patients with mild to moderate AD was effective in reducing the SCORAD after 1 year of SLIT treatment. In addition the treatment was very well tolerated. Treatment with SLIT, furthermore, has allowed a gradual and relevant reduction of concomitant therapies with topical corticosteroids or immunosuppressants. Present results require further controlled trials in order to confirm the potential clinical benefit of SLIT in this clinical setting.     

Effect of improved home ventilation on asthma control and house dust mite allergen levels

Background:  The warm, humid environment in modern homes favours the dust mite population, but the effect of improved home ventilation on asthma control has not been established. We tested the hypothesis that a domestic mechanical heat recovery ventilation system (MHRV), in addition to allergen avoidance measures, can improve asthma control by attenuating re-colonization rates.
Methods:  We conducted a randomized double-blind placebo-controlled parallel group trial of the installation of MHRV activated in half the homes of 120 adults with asthma, allergic to Dermatophagoides pteronyssinus . All homes had carpets steam cleaned and new bedding and mattress covers at baseline. The primary outcome was morning peak expiratory flow (PEF) at 12 months.
Results:  At 12 months, the primary end-point; change in mean morning PEF as compared with baseline, did not differ between the MHRV group and the control group (mean difference 13.5 l/min, 95% CI: −2.6 to 29.8, P  = 0.10). However, a secondary end-point; evening mean PEF, was significantly improved in the MHRV group (mean difference 24.5 l/min, 95% CI: 8.9–40.1, P  = 0.002). Indoor relative humidity was reduced in MHRV homes, but there was no difference between the groups in Der p 1 levels, compared with baseline.
Conclusions:  The addition of MHRV to house dust mite eradication strategies did not achieve a reduction in mite allergen levels, but did improve evening PEF.     

尘螨变应原Der p2基因克隆及原核表达

目的 原核表达尘螨主要变应原DerP 2。方法分离屋尘螨总RNA，根据GenBank已公布的DerP2核酸序列设计引物用RT-PcR扩增DerP2编码基因，克隆至pMD19-T载体、亚克隆至表达载体pET28a（＋），将表达质粒转化至Escherichia coliBL21（DE3）并用IFFG诱导表达，并对表达产物进行免疫印迹鉴定。结果成功构建了表达质粒pET28a（＋）-DerP2，SDS-PAGE和Western blotting显示原核表达获得成功。序列分析表明所获得的DerP2编码基因与参考序列同源性达99．54％，推测其编码氨基酸130个，相对分子质量约为14348．5。结论尘螨变应原DerP2原核表达获得成功，为进一步生产重组变应原奠定了基础。