Is asthma a protective factor for dengue fever? In vitro experiment and nationwide population-based cohort analysis

BackgroundDengue fever (DF) is the most rapidly spreading mosquito-borne viral disease. Practical vaccines or specific therapeutics are still expected. Environmental factors and genetic factors affect the susceptibility of Dengue virus (DV) infection. Asthma is a common allergic disease, with house dust mites (HDMs) being the most important allergens. Asthmatic patients are susceptible to several microorganism infections.MethodsA nationwide population-based cohort analysis was designed to assess whether to determine whether asthma can be a risk factor for DF.ResultsUnexpectedly, our data from a nationwide population-based cohort revealed asthmatic patients are at a decreased risk of DF. Compared to patients without asthma, the hazard ratio (HR) for DF in patients with asthma was 0.166 (95% CI: 0.118–0.233) after adjustment for possible confounding factors. In the age stratification, the adjusted HR for DF in young adult patients with asthma was 0.063. Dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) of dendritic cells (DCs) is an important entry for DV. Through another in vitro experiment, we found that HDM can diminish surface expression of DC-SIGN in monocyte-derived DCs and further decrease the cellular entry of DV.ConclusionsDecreased DC-SIGN expression in DCs of allergic asthmatic patient may be one of many factors for them to be protected against DF. This could implicate the potential for DC-SIGN modulation as a candidate target for designing therapeutic strategies for DF.     

山东省肺螨病病原及流行状况调查

目的了解山东地区肺螨病病原的种类,以及肺螨病在该地区的流行状况。方法在省内8个地区16个县（市）,以普通人群及从事不同行业的重点人群为对象,采用访问法和螨渗液皮肤点刺试验调查肺螨感染情况,计算肺螨感染率,检出的螨虫作分类鉴定;在生活环境及仓储环境采样查螨,并进行螨种鉴定。结果调查普通人群4 622人,肺螨感染率为0.26%;重点人群检查2 754人,肺螨感染率为6.90%,其中粮食加工人员感染率最高,为13.80%,粮食搬运工感染率为10.78%。肺螨感染主要与接触螨类孳生环境的时间长短有关,且随年龄增大感染率升高（P〈0.05）,但性别感染率差异无统计学意义（P〉0.05）。痰检查出螨类4科7属8种,环境螨16种。结论肺螨感染与从事职业有关,在螨类环境中工作年限越长,肺螨感染率越高。粗脚粉螨和粉尘螨为肺螨病的常见致病螨。     

广州城市青少年特应性与支气管哮喘的关系调查

目的了解广州城市青少年特应性的流行情况，探讨特应性与支气管哮喘（简称哮喘）的关系，明确主要的吸人性变应原。方法2002年4至5月在广州市参加儿童哮喘和变应性疾病的国际性对比研究（简称ISAAC）第三阶段调查的10所学校学生中，每所学校以班级为单位进行随机整群抽样调查。采用5组9种吸人性变应原（屋尘螨、粉尘螨、猫毛、美洲大镰、德国小镰、混合草花粉、混合树木花粉、链格孢属真菌、混合霉菌）对1187名学生进行皮肤点刺试验。哮喘定义为：既往或近12个月胸部有喘息声、胸闷或曾被医生诊断为哮喘，有哮喘、鼻炎、湿疹中的任1种疾病视为有变应性疾病史。变应原皮试反应的风团直径大于阴性对照3mm以上为阳性，有1个或以上变应原反应阳性视为特应性。特应性程度及变应原阳性反应强度分别以特应性指数（AI）及皮肤指数（SI）分级表示。结果随机抽取1543人参加调查，实际应答率为77．0％（1187／1543），其中男性为51．6％（613／1187），女性为48．4％（574／1187），年龄12～17岁（中位数14岁）。哮喘的患病率为9．4％（111／1187），其中合并鼻炎率为81．1％（90／111），合并湿疹率为24．3％（27／111）。686例有鼻炎史患者合并哮喘率为[13．1％（90／686）]，高于无鼻炎史者[4．2％（21／501），OR值为3．444，95％可信区间（CI）为2．110～5．622，P〈0．01]；200例有湿疹史患者合并哮喘率为[13．5％（27／200）]，也高于无湿疹史者[8．5％（84／987），OR值为1．676，95％CI为1．055～2．663，P〈0．05]。特应性阳性率为46．3％（549／1187），其中尘螨（屋尘螨、粉尘螨）皮试反应阳性率最高[分别为41．8％（496／1187）、42．7％（507／1187）]。哮喘患者特应性阳性率为[71．2％（79／111）]，高于无变应性疾病者[26．4％（112／425），OR值为6．812，95％CI为4．276～10．853，P〈0．01]，且随着合并其他疾病种类的增加而升高。与特应性阴性者比较，特应性阳性是哮喘的危险因素（OR值为3．183，95％CI为2．075～4．883，P〈0．01），且哮喘的患病风险随着特应性程度的增加而升高。单因素Logistic回归分析结果表明，哮喘的危险因素有屋尘螨（SI≥2）、粉尘螨（SI=3～4）、美洲大蠊、德国小蠊、猫毛、链格孢属、混合草花粉。多因素Logistic回归分析结果表明，屋尘螨（SI=3～4）、链格孢属阳性仍是哮喘独立的危险因素。结论广州城市青少年哮喘患者大多属尘螨变应性的，哮喘的患病风险随着特应性程度及屋尘螨皮试反应强度增加而升高。     

Concentrations of domestic mite and pet allergens and endotoxin in Palestine

BACKGROUND: A few studies have compared indoor allergens and endotoxin levels between urban and rural settings as important determinants for asthma and atopy in children. However, no study was done in the Middle East or investigated refugee camps. METHODS: As part of a nested case-control study in Ramallah in 2001, we measured house dust mite and pet allergens, as well as endotoxin in dust collected from 110 children's mattresses and living room floors. RESULTS: Geometric mean (GM) concentrations of Dermatophagoides pteronyssinus (Der p1) antigen were 4.48 microg/g in mattress dust and 1.23 microg/g floor dust. The highest Der p1 levels were seen in refugee camps. Concentrations of Dermatophagoides farinae antigen (Der f1) were much lower (<0.08 microg/g dust). Concentrations of cat allergen (Fel d1) were highest in villages, and those of dog allergen (Can f1) were highest in mattresses from cities and in floor dust from refugee camps. GM of endotoxin levels were 25.7 EU/mg in mattress dust and 49 EU/mg dust in floor dust. CONCLUSIONS: Concentrations of Der p1 were high compared to Western European countries, but were lower compared to UK and Australia. Levels of pet allergens were lower than in Western Europe. Endotoxin levels were higher compared to developed countries. Indoor environmental factors such as dampness seemed to be important determinants for allergen and endotoxin, but living habits such as lack of mattress cover appeared unimportant.     

Sensitization to Dermatophagoides siboney, Blomia tropicalis, and other domestic mites in asthmatic patients

Mite species adapted to warm, humid climates are commonly found in house dust in the tropics. In Cuba, Dermatophagoides pteronyssinus, D. siboney , and Blomia tropicalis are the most common and abundant mite species in house dust. To investigate the pattern of Sensitization of Cuban asthmatic patients to common mite species, we skin-prick-tested (SPT) 148 patients with a clinical history of asthma and possible mite allergy, and determined specific IgE antibodies against mite allergens ( D. pteronyssinus, D. farinae, D. siboney, B. tropicalis, Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae , and Glycyphagus domesticus ). The prevalence of positive SPT was high to D. siboney (88%), D. pteronyssinus (87%), A. siro (85%), B. tropicalis (85%), and D. farinae (83%). The largest skin reactions were obtained with D. siboney and B. tropicalis extracts. The skin test response to the D. siboney extract correlated to those of D. farinae, D. pteronyssinus, B. tropicalis , and A. siro. The highest IgE levels were found to Dermatophagoides species and B. tropicalis. IgE to D. siboney and B. tropicalis were found in 97% and 96% of the patients, respectively. The prevalence of specific IgE to the other mites studied varied from 46 to 65%. D. siboney and B. tropicalis are important sensitizers among asthmatic patients in Cuba.     

New feather mite species (Acari,Astigmata) from the Sulphur-crested Cockatoo <Emphasis Type="Italic">Cacatua galerita</Emphasis> and Yellow-crested Cockatoo <Emphasis Type="Italic">C. sulphurea</Emphasis> (Psittaciformes,Cacatuidae)

Two new genera and three new species of feather mites (Astigmata, Pterolichoidea, Analgoidea) are described from two closely related species of cockatoos, Cacatua galerita (type host) and C. sulphurea (Psittaciformes, Cacatuidae): Astrolabelichus caudatus gen. nov., sp. nov. (Pterolichidae), Psittophagus lacunosus sp. nov. (Pterolichidae), and Cacatualges microdiscus gen. nov., sp. nov. (Xolalgidae). The presence of the same set of mite species on these two species of parrots points to a very close affinity of Cacatua sulphurea and C. galerita and gives additional support for the recent hypothesis of the conspecificity of these birds.     

Prevalence and residential determinants of fungi within homes in Melbourne, Australia

BACKGROUND: Recent epidemiological studies suggest that the adverse respiratory health effects caused by the inhalation of fungal propagules are substantial. Knowledge of the prevalence and environmental determinants of indoor fungal levels is essential in designing effective avoidance measures. AIM: To investigate the prevalence of fungi and the influence of residential characteristics on levels of fungi within homes in Melbourne, Australia. METHODS: Floor dust and air samples were collected from bedrooms in 485 houses over 1 year. The dust was analysed for ergosterol, a marker of cumulative fungal biomass exposure. Total and genera-specific fungal propagules were identified in air samples. Details of the relevant residential characteristics were documented using a questionnaire. Independent predictors (P < 0.05) of ergosterol and total fungal propagules were identified by multiple linear regression. RESULTS: Fifty-five percent of the houses had viable fungal propagules exceeding 500 CFU/m3. Cladosporium and Penicillium were identified as the most prevalent and abundant fungal genera in indoor air. The median ergosterol level in bedroom floor was 3.8 microg/g of dust. Multivariate analysis showed that total fungal propagules in indoor air were lower in bedrooms with a ceiling fan, without visible mould, and those that were more frequently vacuumed, had a solid fuel fire, had windows closed at the time of the sampling or lacked pets. The presence of more than one cat had the greatest effect on total fungal propagules. Ergosterol levels were significantly lower in homes without old fitted carpets, visible mould or pets and those with frequent airing and regular use of an extractor fan in the kitchen. Old wall-to-wall carpets had the greatest effect on ergosterol. CONCLUSIONS: High indoor fungal exposures were associated with infrequent ventilation or vacuuming, presence of pets, visible mould and old carpets.     

Use of a chimeric ELISA to investigate immunoglobulin E antibody responses to Der p 1 and Der p 2 in mite-allergic patients with asthma, wheezing and/or rhinitis

BACKGROUND: Sensitization to indoor allergens, particularly to dust mites, is a strong risk factor for asthma in children and adults. Assessment of sensitization is carried out using in vivo and in vitro tests to detect specific IgE antibodies. OBJECTIVE: To investigate IgE antibody responses to mites in patients with asthma, wheezing and/or rhinitis, using chimeric ELISA to measure specific IgE antibodies to mite allergens Der p 1 and Der p 2. METHODS: Specific IgE antibodies to Der p 1 and Der p 2 were quantified by chimeric ELISA, and compared with IgE to Dermatophagoides pteronyssinus (Dpt) measured using the CAP system (Pharmacia). A panel of sera from 212 patients with asthma, wheezing and/or rhinitis and 11 controls was analysed. RESULTS: There was a significant correlation between IgE to Dpt measured by CAP and IgE to Der p 1 (r = 0.81, P < 0.001), Der p 2 (r = 0.79, P < 0.001) and combined Der p 1 and Der p 2 (r = 0.86, P < 0.001). Seventy per cent of all patients had IgE to Dpt, and of those, 76.5% had IgE to Der p 1, 79.2% had IgE to Der p 2 and 83.1% had IgE to Der p 1 and Der p 2 combined. Considering the cut-off level of 2 IU/mL of IgE to either Der p 1 or Der p 2, the predictive value for a positive IgE to Dpt by CAP was greater than 95%. CONCLUSIONS: The chimeric ELISA allowed accurate quantification of IgE antibodies to Dpt allergens Der p 1 and Der p 2, and it could be useful for studying immune responses to mites in patients with asthma and/or rhinitis.     

The unfavorable effects of concomitant asthma and sleeplessness due to the atopic eczema/dermatitis syndrome (AEDS) on quality of life in subjects allergic to house-dust mites

BACKGROUND: Allergic rhinitis, asthma or the atopic eczema/dermatitis syndrome (AEDS) may independently impair quality of life in patients. However, although many allergic patients may suffer from more than one disorder, the effect of concomitant disease -- in particular, the impact of AEDS -- is largely unknown. As part of a large multicenter clinical trial on the efficacy of mattress casings in house-dust mite (HDM) allergy, generic quality of life in a mixed population of 224 subjects with rhinitis (n = 198) and/or asthma (n = 111) and/or AEDS (n = 64) was studied. The study aimed to estimate quality of life impairment in these atopic patients and to address the question/issue of whether one atopic disorder goes beyond other existing allergic diseases, thereby causing further impairment to quality of life. METHODS: Generic quality of life was assessed by SF-36. Quality of life in the atopic group was compared with a Dutch norm population. Multiple linear regression was used to determine the effects of disease (i.e. the presence of allergic rhinitis, asthma or AEDS) or disease severity, as assessed by visual analog scores (VAS) for asthma, rhinitis, VAS sleeplessness and VAS itching being considered as major symptoms in AEDS on SF-36 domains. RESULTS: Compared to the norm group, atopic patients were impaired in: physical functioning; role physical functioning; general health; vitality; and social functioning. The diagnosis of asthma was negatively associated with the SF-36 subscales for physical functioning (P = 0.02), and general health (P < 0.01). In line with these findings, asthma severity (VAS asthma) was negatively associated with physical functioning (P < 0.01), role physical functioning (P < 0.01), general health (P < 0.0.1), social functioning (P = 0.01), emotional functioning (P = 0.01), and vitality (P = 0.01). VAS sleeplessness had significant negative effect on role physical functioning (P < 0.01), bodily pain (P < 0.01), General health (P = 0.01), mental health (P < 0.01), social functioning (P < 0.01), and vitality (P < 0.01). In contrast, neither the diagnosis of allergic rhinitis or AEDS, nor VAS itching as an outcome parameter of AEDS, exerted additional effects on the SF-36 domains. CONCLUSIONS: Patients with atopic disease based on HDM allergy may have impaired quality of life. The majority of these patients have allergic rhinitis. The (co)existence of asthma, expressed in terms of diagnostic criteria or symptom severity, or the presence of sleep disorders as a consequence of AEDS, may further impair quality of life.