BACKGROUNDCockroaches are an important indoor allergen source causing allergic rhinitis and asthma. The aim of this study was to investigate the cockroach prevalence in mainland of China and the cross-reactivity of IgE between cockroach and house dust mite allergen in Chinese patients.

METHODSThe cockroach sensitization pattern was based on a skin prick test (SPT) obtained from a national multicenter prevalence study, in which 6304 patients from 25 allergy centers across China participated. Factors, including different regions of China, age, gender and the correlations between the American and German cockroaches and house dust mite Der p were investigated. Eighteen out of 1236 clinical sera from south China were selected to perform the cross-inhibition assay between house dust mites and cockroaches.

RESULTSTotally 25.7% of patients were SPT positive to the American cockroach (Periplaneta Americana, Per a) and 18.7% SPT positive to the German cockroach (Blattella germanica, Bla g). The prevalence of positive cockroach SPT was higher in southern than in northern China, higher in adults than in children, and higher in males than in females. Patients had relatively low levels of cockroach SPT reactions, mainly class 1 or 2. Of the SPT positive cockroach patients, 88% were also SPT positive to house dust mite (Dermatophagoides pteronyssinus, Der p). An IgE cross-inhibition study confirmed that Der p sensitization could cause false positive SPT reactions against cockroach.

CONCLUSIONSA relatively high prevalence of cockroach sensitivity was found in mainland of China. However, a cross-inhibition study showed that only a small number of patients appear to have Bla g and/or Per a as primary sensitizing source. The importance of cockroaches as a risk factor for sensitization and triggers of allergic symptoms in mainland of China needs to be further investigated.

Adolescent ; Adult ; Aged ; Allergens ; immunology ; Animals ; Antigens, Dermatophagoides ; immunology ; Asthma ; etiology ; Child ; Child, Preschool ; China ; epidemiology ; Cockroaches ; immunology ; Cross Reactions ; Female ; Humans ; Hypersensitivity ; epidemiology ; Immunoglobulin E ; immunology ; Male ; Middle Aged ; Prevalence ; Rhinitis, Allergic, Perennial ; etiology ; Rhinitis, Allergic, Seasonal ; etiology

BACKGROUNDHaikou locates in tropical island with unique mite propagation. The aim of this stuy is to determine mite allergens levels in Haikou, and to investigate the prevalence of mite specific IgE-sensitization and IgE cross-reactivity between house dust mites.

METHODSAllergen and antigen concentrations against six mite species were tested by enzyme-linked immunosorbent assay (ELISA). Specific IgE concentrations and cross-inhibitions were measured with ADVIA Centaur(®).

RESULTSAllergen or antigen Dermatophagoides pteronyssinus (Der p 1), Blomia tropicalis (Blo t) and Tyrophagus putrescentia (Tyr p) were detected in dust samples. Dermatophagoides farinae (Der f 1), Lepidoglyphus destructor (Lep d 2), and Acarus siro (Aca s) were found in very few samples. Specific IgE tests showed high prevalence of sensitizations against all tested mites with high IgE levels to Der p, Der f, and Blo t. Storage mites, Blo t, Tyr p, Lep d, and Aca s, could inhibit Der p from 0 to 50%. Storage mites could inhibit Der f between 30% and 100%. Der p IgE could be inhibited by Der f with up to 90%, and vice versa. Der p could inhibit Blo t from 40% to 80%. Blo t was able to fully inhibit IgE binding to Lep d, Tyr p, and Aca s compared to partial inhibition by Der p.

CONCLUSIONSDer p is the dominating mite and has the highest specific IgE prevalence among asthmatic children. Blo t represents an important source of storage mite sensitization and some patients may be independently sensitized to both Der p and Blo t. High prevalence of sensitization to Der f may be due to IgE-mediated cross-reactivity with Der p and Blo t.

Adolescent ; Air Pollution, Indoor ; Allergens ; analysis ; Animals ; Antigens, Dermatophagoides ; analysis ; Arthropod Proteins ; analysis ; Asthma ; immunology ; Child ; Child, Preschool ; China ; Cross Reactions ; Cysteine Endopeptidases ; analysis ; Dust ; Humans ; Immunoglobulin E ; blood ; immunology ; Mites ; immunology

BACKGROUNDAllergen micro-arrays are powerful tools for screening of serum IgE-reactivity. In this study allergen micro-arrays were used to identify dominating IgE-binding allergens and cross-reactivity patterns among selected Chinese allergy patients.

METHODSThe study was conducted using patient sera from the cities of Guangzhou, Nanjing, Chengdu and Shenyang. In total 100 sera with Dermatophagoides pteronyssinus (Der p) specific IgE-levels higher than 50 kU/L were selected for testing against 103 individual allergens.

RESULTSAmong 100 selected patients, 95% showed IgE-reactivity towards house-dust mite allergens Dermatophagoides farinae (Der f) 1, Der f 2 and Der p 2 and 94% were IgE positive against Der p 1, and 60% of sera contained IgE reacting against allergen Euroglyphus maynei (Eur m) 2. IgE against cat allergen, Felisdomesticus (Fel d) 1, was seen in 20%. Only 2% showed specific IgE-reactivity to Der p 10, a panallergen belonging to the tropomyosin family. Serum IgE-reactivity towards other allergens was in general low. IgE-reactivity against pollen allergens showed geographic differences.

CONCLUSIONSThis study clearly confirms that group 1 and group 2 are major allergens of house dust mites. These selected house-dust mite allergy patients are close to being mono-sensitized. Der p 10 is not an important allergen for cross-reactivity. Specific IgE-sensitization towards pollen allergens is low in southern China compared to other regions. The prevalence of food and stinging insect allergens known to give rise to IgE-mediated cross-reactivity is 2% or less.

Adolescent ; Adult ; Allergens ; immunology ; Asian Continental Ancestry Group ; Child ; Child, Preschool ; Female ; Humans ; Hypersensitivity ; blood ; immunology ; Immunoglobulin E ; blood ; genetics ; immunology ; Male ; Middle Aged ; Young Adult

OBJECTIVEChinese allergic subjects have high levels of sensitization to house dust mite (HDM) and other indoor allergens. This study quantifies common indoor allergen levels in Chinese households.

METHODSDust samples were collected from nine cities. Major allergens Der p 1 and Der f 1 from Dermatophagoides pteronyssinus and D. farinae, and specific antigens of Blomia tropicalis, Tyrophagus putrescentiae, Acarus siro, and cockroach species Blattella germanica and Periplaneta americana were measured by ELISA.

RESULTSHDM allergens were found in dust samples from bedding in 95% of the Chinese households. The median levels varied from <0.006 to 9.2 µg/g of dust, depending on the city. The percentages of households having HDM allergen levels associated with the risk of developing allergy sensitization and asthma were 65% and 25%, respectively. Specific antigens of the storage mite and cockroach were only found in samples from the southern and tropical regions of China. Levels of mite allergens were generally higher in samples from bedding compared to samples from the living room, even for storage mites, whereas levels of cockroach antigens were higher in the living room samples.

CONCLUSIONHDM allergens are present in bedding dust samples from most Chinese households. Cities in southern and central China have relatively high levels of HDM major allergens compared to cities in northern and western China. Antigens of storage mites and cockroaches are not as common as HDM allergens.

Air Pollution, Indoor ; statistics & numerical data ; Allergens ; chemistry ; Animals ; Bedding and Linens ; China ; Cockroaches ; Dust ; analysis ; Housing ; Pyroglyphidae ; Seasons