Autologous enzyme-linked immunosorbent facilitated antigen binding detects IgE-blocking activity based on direct competition between allergen-specific IgE and non-IgE.

Aim: To measure IgE-blocking activity induced by allergen immunotherapy (AIT) by an enzyme-linked immunosorbent facilitated antigen binding (ELIFAB) assay based on autologous immunoglobulin competition. Methods: The developed ELIFAB assay was used to investigate the kinetics of IgE-blocking activity in 87 patients at multiple AIT treatment time points, in comparison to the changes in IgG4. Results: High ELIFAB response was observed until 2.5 months of AIT, then significantly decreased after 4 months and remained suppressed during the 3-year AIT period. After treatment cessation, the ELIFAB response was maintained at the level seen at the 4-6 month treatment time point, similar to IgG4, indicating sustained IgE-blocking activity related to IgG4. Conclusion: This ELIFAB assay measures the IgE-blocking activity for autologous allergen-specific IgE and non-IgE during and after immunotherapy. It is suited for measuring the sustained IgE-blocking activity induced by AIT.

Lay abstract Allergy is a serious health problem worldwide. Allergen immunotherapy is a controlled exposure to allergen with the aim of modulating the immune response and reducing symptoms. The immune modulation includes a shift from the production of allergy-inducing IgE antibodies to inhibiting IgG antibodies and the competition between these antibodies for allergen binding when exposed to allergen may be central to the effect of the treatment. The current study addressed several ways of monitoring the changes in IgE and IgG antibodies during house dust mite immunotherapy. A novel assay for monitoring the competitive binding of these antibodies to house dust mite allergen is introduced; it may be used to monitor the immunological changes induced by immunotherapy and help increase treatment compliance.

Associations between the indoor microbiome, environmental characteristics and respiratory infections in junior high school students of Johor Bahru, Malaysia.

Pathogens are commonly present in the human respiratory tract, but symptoms are varied among individuals. The interactions between pathogens, commensal microorganisms and host immune systems are important in shaping the susceptibility, development and severity of respiratory diseases. Compared to the extensive studies on the human microbiota, few studies reported the association between indoor microbiome exposure and respiratory infections. In this study, 308 students from 21 classrooms were randomly selected to survey the occurrence of respiratory infections in junior high schools of Johor Bahru, Malaysia. Vacuum dust was collected from the floor, chairs and desks of these classrooms, and high-throughput amplicon sequencing (16S rRNA and ITS) and quantitative PCR were conducted to characterize the absolute concentration of the indoor microorganisms. Fifteen bacterial genera in the classes Actinobacteria, Alphaproteobacteria, and Cyanobacteria were protectively associated with respiratory infections (p < 0.01), and these bacteria were mainly derived from the outdoor environment. Previous studies also reported that outdoor environmental bacteria were protectively associated with chronic respiratory diseases, such as asthma, but the genera identified were different between acute and chronic respiratory diseases. Four fungal genera from Ascomycota, including Devriesia, Endocarpon, Sarcinomyces and an unclassified genus from Herpotrichillaceae, were protectively associated with respiratory infections (p < 0.01). House dust mite (HDM) allergens and outdoor NO2 concentration were associated with respiratory infections and infection-related microorganisms. A causal mediation analysis revealed that the health effects of HDM and NO2 were partially or fully mediated by the indoor microorganisms. This is the first study to explore the association between environmental characteristics, microbiome exposure and respiratory infections in a public indoor environment, expanding our understanding of the complex interactions among these factors.

The IgE Blocking Activity Induced by Dermatophagoides pteronyssinus Subcutaneous Immunotherapy Does Not Correlate with Specific IgA but with IgG4 in both Serum and Saliva.

BACKGROUND: The role of salivary-specific IgG4 and IgA in subcutaneous immunotherapy (SCIT) is not well defined. We aimed to investigate the change of IgG4 and IgA in both serum and saliva and their correlations with IgE-blocking-factor (IgE-BF) during SCIT. METHOD: 307 Dermatophagoides pteronyssinus (DP) allergic rhinitis and/or asthma patients were recruited for this study. 286 patients received DP-SCIT for 1 year. Twenty-one patients received only symptomatic treatment. DP-, Der p 1-, and Der p 2-specific IgE in serum, specific-IgG4 and Der p 2-specific IgA1 and IgA2 in both serum and saliva were measured at timepoints 0, 4, and 12 months during DP-SCIT. Correlation between salivary and serological IgG4, IgA, and their correlation with DP-specific IgE-BF measured in serum was evaluated. RESULTS: During DP-SCIT, the allergen-specific IgG4 in both saliva and serum increased and correlated significantly, the correlation becomes stronger over the treatment time. DP-specific IgE-BF significantly correlated with DP-specific IgG4 in serum (p < 0.0001) at different timepoints and in saliva at 12 months of SCIT (p < 0.01). No change in Der p 2-specific IgA during DP-SCIT was observed, and the IgA in serum did not correlate with IgA in saliva. There was no correlation between DP IgE-BF and Der p 2-specific IgA in serum or saliva. The control group did not exhibit significant changes in any antibody level measured. CONCLUSION: The IgE blocking activity induced by DP-SCIT treatment correlated with specific IgG4 and not IgA. The IgG4 in saliva correlates with serum IgG4 and can be an alternative immunological marker beyond 1 year of SCIT treatment.

Indoor microbiome, environmental characteristics and asthma among junior high school students in Johor Bahru, Malaysia.

Indoor microbial diversity and composition are suggested to affect the prevalence and severity of asthma by previous home microbiome studies, but no microbiome-health association study has been conducted in a school environment, especially in tropical countries. In this study, we collected floor dust and environmental characteristics from 21 classrooms, and health data related to asthma symptoms from 309 students, in junior high schools in Johor Bahru, Malaysia. The bacterial and fungal composition was characterized by sequencing 16s rRNA gene and internal transcribed spacer (ITS) region, and the absolute microbial concentration was quantified by qPCR. In total, 326 bacterial and 255 fungal genera were characterized. Five bacterial (Sphingobium, Rhodomicrobium, Shimwellia, Solirubrobacter, Pleurocapsa) and two fungal (Torulaspora and Leptosphaeriaceae) taxa were protective for asthma severity. Two bacterial taxa, Izhakiella and Robinsoniella, were positively associated with asthma severity. Several protective bacterial taxa including Rhodomicrobium, Shimwellia and Sphingobium have been reported as protective microbes in previous studies, whereas other taxa were first time reported. Environmental characteristics, such as age of building, size of textile curtain per room volume, occurrence of cockroaches, concentration of house dust mite allergens transferred from homes by the occupants, were involved in shaping the overall microbial community but not asthma-associated taxa; whereas visible dampness and mold, which did not change the overall microbial community for floor dust, was negatively associated with the concentration of protective bacteria Rhodomicrobium (ß = -2.86, p = 0.021) of asthma. The result indicates complex interactions between microbes, environmental characteristics and asthma symptoms. Overall, this is the first indoor microbiome study to characterize the asthma-associated microbes and their environmental determinant in the tropical area, promoting the understanding of microbial exposure and respiratory health in this region.

Clinical Response to Subcutaneous Dermatophagoides pteronyssinus Immunotherapy in Children with Allergic Rhinitis and Asthma Is Independent of Sensitization to Blomia tropicalis Allergens.

BACKGROUND: Dermatophagoides pteronyssinus (DP) and Blomia tropicalis (BT) are the dominant house dust mites inducing allergic diseases in tropical climates. It is not known whether the efficacy of DP subcutaneous immunotherapy (SCIT) is similar in patients sensitized to DP alone or to both DP and BT. METHOD: Ninety-five children (5-17 years old) affected by asthma with rhinitis and sensitized to both DP and BT received 3 years of DP-SCIT. Clinical symptom and medication scores, serum-specific IgE and IgG4 were evaluated during DP-SCIT. Patients were grouped based on DP and BT co-sensitization or cross-reactivity, according to positive or negative IgE to BT major allergen (BTMA). RESULTS: After 3 years of DP-SCIT, all patients had significant reductions in symptoms and medication use. In all, 65% of the patients were free of asthma symptoms and medication use; in addition, 3% was free of rhinitis symptoms. FEV1 in all patients were greater than 95% of predicted. DP-SCIT induced significant increases in DP- and BT-specific IgG4. In 50% of patients, DP-specific IgG4 increased more than 67-fold. BT-specific IgG4 increased more than 2.5 fold. A moderate correlation (r = 0.48-0.61, p < 0.01) was found between specific IgE against DP and BT in the BTMA- group (n = 34) before and after DP-SCIT, whereas no correlation was found in the BTMA+ group (n = 61). The 2 BTMA groups responded similarly with regard to clinical improvement and increase in specific IgG4 to both DP and BT. No safety finding of concern were reported in either group. CONCLUSION: DP-SCIT may be of clinical benefit to patients with IgE sensitizations to both DP and BT. DP-SCIT induces IgG4 that cross-react with BT allergens.

Functional and Immunoreactive Levels of IgG4 Correlate with Clinical Responses during the Maintenance Phase of House Dust Mite Immunotherapy.

Allergen-specific immunotherapy for house dust mite allergy is effective, but there are no validated biomarkers reflecting or predicting the clinical efficacy. We aimed to investigate the relationship between clinical outcomes and functional responses of allergen-specific IgG4 (sIgG4) and specific IgE (sIgE) during Dermatophagoides pteronyssinus s.c. allergen immunotherapy (SCIT) in allergic rhinitis and/or asthma patients. Combined symptom medication scores (SMS), D. pteronyssinus-sIgG4 levels, D. pteronyssinus-sIgE levels, and the serum inhibitory capacity against D. pteronyssinus-sIgE facilitated allergen binding to B cells (IgE-FAB) were determined during the updosing (week 0, 4, 12, and 16) and maintenance (week 52, 104, and 156) phase of SCIT. We found that SCIT patients had a significant improvement in SMS from week 52 to 156 compared with medication-treated control subjects (p < 0.05). Levels of D. pteronyssinus-sIgG4 in SCIT patients showed a significant increase from week 12 to 156 (p < 0.05). Serum obtained from SCIT patients significantly inhibited D. pteronyssinus-sIgE binding to B cells after 16 wk (p < 0.01). Significantly lower levels of D. pteronyssinus-sIgE were observed in SCIT patients after 52 wk (p < 0.05). A significant relationship was demonstrated between SMS and IgE-FAB or D. pteronyssinus-sIgG4 during the maintenance phase according to linear regression analysis. In conclusion, D. pteronyssinus-sIgG4 level and D. pteronyssinus IgE-FAB are associated with clinical efficacy in the maintenance phase rather than the updosing phase of SCIT. Immunologic tolerance can be induced with SCIT when maintenance phase is achieved.

Self-reported questionnaire survey on the prevalence and symptoms of adverse food reactions in patients with chronic inhalant diseases in Tangshan city, China.

BACKGROUND: The prevalence of adverse food reactions in patients with chronic inhalant diseases has seldom been studied in China. This study is to investigate the prevalence of adverse food reactions and the symptoms caused in respiratory patients. METHODS: Respiratory patients in allergy clinics were asked to complete a questionnaire. Patients' information such as age, gender, family history of allergy, and adverse reactions to a list of 48 foods and the symptoms caused, was recorded. Multivariate analyses were performed to determine the prevalence of adverse food reactions and their associated symptoms. RESULTS: 459 subjects, with an average age of 32 years old, completed the questionnaire; 45.3% were male. Among the 459 subjects, 38.1% (175/459) had an adverse reaction to food: 13.6% had an adverse food reaction to crab, 12.4% had an adverse food reaction to shrimp; and 9.9% had an adverse reaction to shellfish. Peach and nectarine were also shown to be common causative foods with 6.8% of the study group showing an adverse reaction to peach and 5.2% to nectarine. Seafood mainly caused skin symptoms and fruits gave rise to more throat, oral, and gastrointestinal problems. CONCLUSION: The prevalence of adverse food reactions is high for patients with respiratory diseases. This indicates that adverse food reactions should be considered in the treatment and management of patients with chronic inhalant diseases.

Specific immunoglobulin E and immunoglobulin G4 toward major allergens of house-dust mite during allergen-specific immunotherapy.

BACKGROUND: Specific immunoglobulin E (sIgE) and sIgG4 to house-dust mite (HDM) major allergens during allergen immunotherapy (AIT) and their clinical relevance remain unclear. OBJECTIVE: To investigate the variation of sIgE and sIgG4 to HDM major allergens and the correlation with clinical responses during AIT in patients with allergic rhinitis. METHODS: Thirty-nine patients with HDM allergy were divided into the AIT group (taking immunotherapy) and the control group (medication only use). The AIT group was subdivided into negative clinical responses to AIT (nAIT) group and positive clinical responses to AIT (pAIT) group according to symptom relief and subjective evaluation. sIgE and sIgG4 to Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df), and their group 1 and group 2 major allergens (Dp1, Df1, Dp2, and Df2) were measured before AIT, at 6 months, and at 1 year after starting AIT. RESULTS: Dp2, Df, and Df2 sIgE values decreased significantly in the pAIT group versus the nAIT group after 1 year of AIT (median values of delta change were Dp2, -10.09 versus 5.89 kU/L, p = 0.001; median values of Df were -9.69 versus 17.54 kU/L, p = 0.004; median values of Df2 were -11.06 versus 20.08 kU/L, p = 0.013). There was a robust increase in the sIgG4 values to Dp, Df, and their major allergens in both the pAIT and the nAIT groups overall after 1 year of treatment. CONCLUSION: Patients with a positive response to AIT showed a significant reduction of HDM group 2 sIgEs compared with those with a negative response to AIT, which indicated that a decrease in group 2 sIgEs could be a marker that reflected AIT clinical efficacy.

High correlation of specific IgE sensitization between birch pollen, soy and apple allergens indicates pollen-food allergy syndrome among birch pollen allergic patients in northern China.

BACKGROUND: Birch pollen sensitization and associated pollen-food syndrome among Chinese allergic patients have not been investigated. METHODS: Sera from 203 allergic patients from the northern part of China and collected during February to July 2014 were investigated. Specific immunoglobulin E (IgE) against birch pollen extract Bet v and major birch pollen allergen Bet v 1 were measured using the ADVIA Centaur. The presence of major apple allergen Mal d 1 and soy bean allergen Gly m 4 specific IgE was measured by ImmunoCAP 100. RESULTS: Among the 203 sera, 34 sera (16.7%) had specific IgE to Bet v and of these, 28 sera (82.4%) contained Bet v 1-specific IgE. Among the 28 sera with Bet v 1-specific IgE, 27 sera (96.4%) contained Mal d 1-specific IgE and 22 sera (78.6%) contained Gly m 4-specific IgE. Of the 34 Bet v-positive sera, 6 sera (17.6%) contained no specific IgE for Bet v 1, Mal d 1, or Gly m 4. Almost all Bet v-positive sera were donated during the birch pollen season. CONCLUSIONS: The prevalence of birch allergy among patients visiting health care during pollen season can be as high as 16.7% in Tangshan City. The majority of Chinese birch allergic patients are IgE-sensitized to the major birch pollen allergen Bet v 1 as well as to the major apple allergen Mal d 1 and soy bean allergen Gly m 4. A relatively high number of patients (17.6%) are IgE-sensitized to birch pollen allergen(s) other than Bet v 1. The high prevalence of specific IgE to Mal d 1 and Gly m 4 among Bet v 1-sensitized patients indicates that pollen-food allergy syndrome could be of clinical relevance in China.

The Functional IgE-Blocking Factor Induced by Allergen-Specific Immunotherapy Correlates with IgG4 Antibodies and a Decrease of Symptoms in House Dust Mite-Allergic Children.

BACKGROUND: At present, there are no validated biomarkers reflecting or predicting the clinical efficacy of allergen-specific immunotherapy (AIT) . We aimed to investigate the correlations between clinical and immunological responses of patients undergoing house dust mite (HDM) AIT. METHODS: Sixty-nine children diagnosed with HDM allergic rhinitis and/or asthma received standardized Dermatophagoides pteronyssinus (Dp) subcutaneous AIT for 12 months. Twenty HDM-allergic children served as an open control group. Clinical symptom and medication scores were recorded and Dp-specific IgE, IgG4 and IgE-blocking factor were measured before AIT and after 4 and 12 months of AIT. RESULTS: Symptom scores decreased after 4 months and continued to decrease during 12 months of AIT. No differences in medication scores were observed between AIT and the control group during the study period. Levels of Dp IgG4 increased after 4 months and correlated to symptom scores at 12 months (r = -0.296, p = 0.013) of AIT. The Dp IgE-blocking factor increased after 4 months of AIT, and correlated with symptom scores at 4 months (r = -0.307, p = 0.010) and 12 months (r = -0.288, p = 0.016) of AIT. A strong correlation between Dp IgE-blocking factor and Dp IgG4 during AIT (4 months: r = 0.680; 12 months: r = 0.636, both p < 0.0001) was observed. Patients with IgE-blocking factor ≥0.2 after 4 months of AIT showed lower symptom scores at 12 months of AIT (p = 0.0093). CONCLUSIONS: Subcutaneous HDM AIT results in a decrease of allergic symptoms among HDM-allergic children. IgE-blocking activity increased after 4 months of AIT and correlated with clinical symptoms. A high IgE-blocking factor at an early stage of AIT is associated with fewer symptoms at a later stage of AIT.

Associations of Early Life Exposures and Environmental Factors With Asthma Among Children in Rural and Urban Areas of Guangdong, China.

BACKGROUND: Environmental factors may play important roles in asthma, but findings have been inconsistent. OBJECTIVE: The goal of this study was to determine the associations between early life exposures, environmental factors, and asthma in urban and rural children in southeast China. METHODS: A screening questionnaire survey was conducted in 7,164 children from urban Guangzhou and 6,087 from rural Conghua. In the second stage, subsamples of 854 children (419 from Guangzhou, 435 from Conghua) were recruited for a case-control study that included a detailed questionnaire enquiring on family history, early life environmental exposures, dietary habits, and laboratory tests (including histamine airway provocation testing, skin prick tests, and serum antibody analyses). House dust samples from 76 Guangzhou families and 80 Conghua families were obtained to analyze levels of endotoxins, house dust mites, and cockroach allergens. RESULTS: According to the screening survey, the prevalence of physician-diagnosed asthma was lower in children from Conghua (3.4%) than in those from Guangzhou (6.9%) (P < .001). A lower percentage of asthma was reported in rural subjects compared with urban subjects (2.8% vs. 29.4%; P < .001) in the case-control study. Atopy (OR, 1.91 [95% CI, 1.58-2.29]), parental atopy (OR, 2.49 [95% CI, 1.55-4.01]), hospitalization before 3 years of age (OR, 2.54 [95% CI, 1.37-4.70]), high consumption of milk products (OR, 1.68 [95% CI, 1.03-2.73]), and dust Dermatophagoides farinae group 1 allergen (OR, 1.71 [95% CI, 1.34-2.19]) were positively associated with asthma. Living in a crop-farming family at < 1 year of age (OR, 0.15 [95% CI, 0.08-0.32]) and dust endotoxin levels (OR, 0.69 [95% CI, 0.50-0.95]) were negatively associated with asthma. CONCLUSIONS: Rural children from an agricultural background exhibited a reduced risk of asthma. Early life exposure to crop farming and high environmental endotoxin levels might protect the children from asthma in southern China.

Endotoxin, ergosterol, fungal DNA and allergens in dust from schools in Johor Bahru, Malaysia- associations with asthma and respiratory infections in pupils.

There are few studies on associations between respiratory health and allergens, fungal and bacterial compounds in schools in tropical countries. The aim was to study associations between respiratory symptoms in pupils and ethnicity, chemical microbial markers, allergens and fungal DNA in settled dust in schools in Malaysia. Totally 462 pupils (96%) from 8 randomly selected secondary schools in Johor Bahru, Malaysia, participated. Dust was vacuumed from 32 classrooms and analysed for levels of different types of endotoxin as 3-hydroxy fatty acids (3-OH), muramic acid, ergosterol, allergens and five fungal DNA sequences. Multiple logistic regression was applied. Totally 13.1% pupils reported doctor's diagnosed asthma, 10.3% wheeze and 21.1% pollen or pet allergy. Indian and Chinese children had less atopy and asthma than Malay. Carbon dioxide levels were low (380-690 ppm). No cat (Fel d1), dog (Can f 1) or horse allergens (Ecu cx) were detected. The levels of Bloomia tropicalis (Blo t), house dust mite allergens (Der p 1, Der f 1, Der m 1) and cockroach allergens (Per a 1 and Bla g 1) were low. There were positive associations between levels of Aspergillus versicolor DNA and daytime breathlessness, between C14 3-OH and respiratory infections and between ergosterol and doctors diagnosed asthma. There were negative (protective) associations between levels of C10 3-OH and wheeze, between C16 3-OH and day time and night time breathlessness, between cockroach allergens and doctors diagnosed asthma. Moreover there were negative associations between amount of fine dust, total endotoxin (LPS) and respiratory infections. In conclusion, endotoxin at school seems to be mainly protective for respiratory illness but different types of endotoxin could have different effects. Fungal contamination measured as ergosterol and Aspergillus versicolor DNA can be risk factors for respiratory illness. The ethnical differences for atopy and asthma deserve further attention.

Prevalence of sensitization to weed pollens of Humulus scandens, Artemisia vulgaris, and Ambrosia artemisiifolia in northern China.

OBJECTIVE: Weed pollens are common sources of allergens worldwide. The prevalence of weed pollen sensitization is not yet fully known in China. The purpose of this study was to investigate the prevalence of sensitization to weed allergens from Artemisia, Ambrosia, and Humulus in northern China. METHODS: A total of 1144 subjects (aged from 5 to 68 years) visiting our clinic from June to October 2011 underwent intradermal testing using a panel of 25 allergen sources. Subjects with positive skin responses to any pollen were further tested for their serum concentrations of IgE antibodies against Artemisia vulgaris, Ambrosia artemisiifolia, and Humulus scandens, and against the purified allergens, Art v 1 and Amb a 1. RESULTS: Of 1144 subjects, 170 had positive intradermal reactions to pollen and 144 donated serum for IgE testing. The prevalence of positive intradermal responses to pollens of Artemisia sieversiana, Artemisia annua, A. artemisiifolia, and H. scandens was 11.0%, 10.2%, 3.7%, and 6.6%, respectively. Among the intradermal positive subjects, the prevalence of specific IgE antigens to A. vulgaris was 58.3%, to A. artemisiifolia 14.7%, and to H. scandens 41.0%. The prevalence of specific IgE antigens to the allergen Art v 1 was 46.9%, and to Amb a 1 was 11.2%. The correlation between the presence of IgE antibodies specific to A. vulgaris and to the Art v 1 antigen was very high. Subjects with A. artemisiifolia specific IgE also had A. vulgaris specific IgE, but with relatively high levels of A. vulgaris IgE antibodies. There were no correlations between the presence of IgE antibodies to H. scandens and A. vulgaris or to H. scandens and A. artemisiifolia. CONCLUSIONS: The intradermal prevalence of weed pollen sensitization among allergic subjects in northern China is about 13.5%. Correlations of specific IgE antibodies suggest that pollen allergens from Artemisia and Humulus are independent sources for primary sensitization.

Specific IgG4 production during house dust mite immunotherapy among age, gender and allergic disease populations.

BACKGROUND: Specific IgG4 induced by allergen-specific immunotherapy (SIT) is an immunological marker related to the appearance of clinical tolerance. But specific IgG4 levels in different age, gender and allergic disease populations have not been fully investigated. METHODS: This study involved 226 children and 109 adults with allergic rhinitis and/or asthma receiving a 156-week course of Dermatophagoides pteronyssinus (Der p) subcutaneous SIT. Symptom and medication scores, forced expiratory volume after 1 s (FEV(1)) and Der p-specific IgG4 levels at weeks 0, 5, 10, 25, 52, 104 and 156 were analyzed. RESULTS: Rhinitis symptom and medication scores and FEV(1) % predicted in children showed significantly greater improvement than in adults at week 104 and 156 (p < 0.05). Levels of Der p-specific IgG4 showed a significant increase after 10 weeks of subcutaneous SIT (p < 0.0001) and continued to increase during the 156-week SIT period. Before SIT, the initial Der p-specific IgG4 level was higher in children than adults (p = 0.0004). The increase ratio of Der p-specific IgG4 was higher in children than adults at 52 weeks (p < 0.001) and 104 weeks (p = 0.0156) of SIT, and was higher in rhinitis compared to asthma patients at 156 weeks of SIT (p = 0.0244). There was no difference between males and females at any time points. CONCLUSION: Children are more responsive to SIT, demonstrating clinical and FEV(1) improvement and producing higher levels of allergen-specific IgG4 during a shorter SIT period compared to adults. Rhinitis patients show a higher increase in specific IgG4 compared to patients with asthma symptoms. The increase of Der p-specific IgG4 reflects a specific response of the immune system towards the SIT vaccine being administrated.

Indoor mite allergen levels, specific IgE prevalence and IgE cross-inhibition pattern among asthmatic children in Haikou, southern China.

BACKGROUND: Haikou 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. METHODS: Allergen 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(®). RESULTS: Allergen 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. CONCLUSIONS: Der 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.

Factors associated with allergen sensitizations in patients with asthma and/or rhinitis in China.

BACKGROUND: Allergen sensitization is influenced by genetic and environmental factors; however, the factors related to sensitizations in patients with rhinitis and asthma in China are largely unknown. This study investigated the factors associated with allergen sensitizations in patients with asthma and rhinitis in China. METHODS: A cross-sectional survey was performed in 6304 patients with asthma and/or rhinitis from four regions of China. Patients completed a standardized questionnaire related to respiratory and allergic symptoms, family history of allergic diseases, smoking history, environmental exposure, and eating behaviors. They underwent skin-prick tests (SPTs) with 13 common aeroallergens. Blood samples were collected from 2268 of patients for specific IgE (sIgE) measurements against 16 common aeroallergens. RESULTS: Patients with both asthma and rhinitis had higher prevalence of SPT and sIgE positivity to most allergens than those with asthma or rhinitis alone (p < 0.0001). Male gender, family history of allergic rhinitis, air-conditioner usage, sleeping on a mattress, and frequently eating meat were associated with increased risk of SPT and sIgE positivity. Using air-conditioner and sleeping on a mattress were further found to be associated with sIgE positivity to mites and molds. However, increased age and fish, fruit, and raw vegetable intake decreased the risk of SPT and sIgE positivity. CONCLUSION: Family history of allergic rhinitis, male gender, using an air conditioner, sleeping on a mattress, and frequent meat consumption are risk factors for allergen sensitizations, whereas increased age and frequent fish, fruit, and raw vegetable consumption may protect patients with asthma and/or rhinitis from developing sensitizations in China.

House dust mite and storage mite IgE reactivity in allergic patients from Guangzhou, China.

BACKGROUND: In China, house dust mites are important inducers of allergic disease. The importance of allergens from storage mites is less well known. OBJECTIVE: The aim of this study is to access the prevalence of house dust mite and storage mite sensitization and investigate the IgE crossreactivity between house dust mite and storage mite. METHOD: The skin prick test (SPT) and specific IgE against the mite species D. pteronyssinus, D. farinae, B. tropicalis, Lepidoglyphus destructor, Glycyphagus domesticus, Tyrophagus putrescentiae and Acarus siro were measured. Included were 412 patients with asthma and/or rhinitis for SPT, 244 for specific IgE and 29 sera for IgE inhibition studies. RESULTS: The positive SPT prevalence for D. pteronyssinus was 80.3% and for D. farinae 83.7%. The specific IgE prevalence for D. pteronyssinus was 61.1% and for D. farinae 60.2%. The storage mite species, B. tropicalis and T. putrescentiae had the highest positive SPT prevalence, 66% and 63%, respectively. The specific IgE prevalence was highest for B. tropicalis and G. domesticus, 41% and 37%, respectively. Both SPT and specific IgE levels were much higher for house dust mites compared to storage mites. Inhibition measurements showed that none of the storage mites could fully inhibit the specific IgE against D. pteronyssinus. Only in half of the sera could D. pteronyssinus fully inhibit the IgE against L. destructor and G. domesticus while inhibition of the other storage mites were much lower. Nearly all the specific IgE against storage mites could be inhibited by the other storage mites, though B. tropicalis showed a slightly different pattern from the other storage mites. CONCLUSION: IgE reactivity against storage mites in Chinese patients is due to both storage mite specific IgE and due to IgE mediated crossreactivity to D. pteronyssinus.

Allergen micro-array detection of specific IgE-reactivity in Chinese allergy patients.

BACKGROUND: Allergen 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. METHODS: The 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. RESULTS: Among 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. CONCLUSIONS: This 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.

The specific IgE reactivity pattern of weed pollen-induced allergic rhinitis patients.

CONCLUSION: Specific immunoglobulin E (IgE) reactivity towards the major mugwort allergen Art v 1 is a good indicator for Art v sensitization. Allergens from the ragweed species Amb t and Amb a possibly share common IgE-binding epitopes. OBJECTIVE: The aim of this study was to investigate the reactivity pattern of IgE in Chinese patients with weed pollen-induced allergic rhinitis. METHODS: Sera from 50 weed pollen-induced allergic rhinitis patients were tested for specific serum IgE reactivity against allergenic extracts of mugwort (Artemisia vulgaris, Art v), short ragweed (Ambrosia artemisiifolia, Amb a), giant ragweed (Ambrosia trifida, Amb t), and single allergens of Art v 1, Art v 3, Amb a 1, and profilin. RESULTS: Sera from 88% of the patients demonstrated positive specific IgE reactivity to Art v, and of these 82% were positive to Art v 1. Sera from 38% of the patients showed positive specific IgE reactivity to both ragweed species Amb t and Amb a. A strong correlation was found between the specific IgE levels of Amb t and Amb a. Of the Amb a IgE-positive patients, 38% were positive for Amb a 1. Of all patient sera tested, 12% were specific IgE-positive to profilin.

Prevalence of sensitivity to cockroach allergens and IgE cross-reactivity between cockroach and house dust mite allergens in Chinese patients with allergic rhinitis and asthma.

BACKGROUND: Cockroaches 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. METHODS: The 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. RESULTS: Totally 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. CONCLUSIONS: A 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.