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Background: Eczema is a known risk factor for the development of wheeze in childhood. Cord blood T-cell cytokine responses have been shown to be associated with the development of both early childhood eczema and wheeze. Our objective is to study and compare the influence of intrinsic T-cell cytokine responses on the development of wheezing and eczema in the first 2 years of life in a birth cohort of at risk (first degree family with atopic disease) infants., Methods: Cord blood samples were collected from 195 eligible subjects of a birth cohort of 253 subjects. The subjects studied were those who developed either wheezing (n = 34) or eczema (n = 29) in the first 2 years of life, and 65 healthy infants served as control. Cytokines from phytohaemagglutinin stimulated mononuclear cells were analyzed using multiplex cytokine assays and the cytokine profiles in the 3 groups were compared., Results: Most of the subjects were non-atopic with only 3/34 (9%) wheeze and 9/29 (31%) eczema subjects sensitized to the common dietary or inhalant allergens. After adjustment for potential risk factors, wheeze, but not eczema subjects, presented with hyper-responsive cytokine profiles with increased production of T-cell cytokines IL-2 and IL-5. IL-5 was the strongest risk factor associated to the development of wheeze at 2 years of age (OR, 35; 95% CI, 5.0 -246.7)., Conclusion: Cord blood cytokine responses in early onset wheeze and eczema are distinctly different. This suggests that the tendency to develop early onset wheeze may be influenced by preexisting immune factors independent to those for eczema.

Objective: To determine the use and efficacy of sublingual immunotherapy (SLIT) for house dust mite (HDM) allergies in Southeast Asian children., Data Sources: Aliterature search was performed in Pubmed and the Asian Pacific Journal of Allergy and Immunology. We also evaluated the literature for similar studies performed in Asia., Study Selections: Clinical trials involving children that assess SLIT for HDM allergies in Southeast Asia and Asia., Results: There are no published studies on the use of SLIT for HD Mallergies in Southeast Asian children. However, there are seven studies from Asia which show that there are discrepancies over the benefits of SLIT for HDM allergies in Asian children. Limitations in these studies include small sample sizes and short study periods., Conclusions: We cannot say with certainty what the impact of SLIT is on HDM allergies in Southeast Asian children due to the lack of data. The available studies performed in Asia have their limitations but are suggestive of the potential of SLIT for HDM allergies in Southeast Asian children. This review highlights that good quality clinical research in this area in the Southeast Asian setting is warranted.

Background and Objective: Shellfish forms a common food source in the Asia-Pacific and is also growing in the West. This review aims to summarize the current literature on the epidemiology and research on shellfish allergy with particular focus on studies emerging from the Asia-Pacific region., Data Sources: A PubMed search using search strategies "Shellfish AND Allergy", "Shellfish Allergy Asia", and "Shellfish AND anaphylaxis" was made. In all, 244 articles written in English were reviewed., Results: Shellfish allergy in the Asia-Pacific ranks among the highest in the world and is the most common cause of food-induced anaphylaxis. Shellfish are classified into molluscs and arthropods. Of the arthropods, the crustaceans in particular Penaeid prawns are the most common cause of allergy and are therefore most extensively studied. Several classes of allergens have been identified. The tropomyosins (class 1 allergens) are the best defined. Despite the establishment of molecular homology and allergenic cross reactivity between allergens of the same class, clinical cross-reactivity is more variable between patients and less clearly defined. There are two relatively unique clinical manifestations of IgE-mediated prawn allergy: (1) isolated oral allergy symptoms; and (2) wide spectrum of severity and sometimes even within the same individual., Conclusion: Shellfish allergy is common in the Asia Pacific. More research including food challenge-proven subjects are required to establish the true prevalence, as well as to understand clinical cross reactivity and variations in clinical features.

This study presents two patients who developed anaphylaxis after eating mite-contaminated food, and also contains a survey of dust-mites contamination in flour samples from Singapore households. The clinical records of each patient was studied. Patient A developed anaphylaxis twenty minutes following the ingestion of home-made fried fish coated with Japanese flour, while Patient B developed similar life-threatening symptoms one hour after the ingestion of home baked scones. Both patients were NSAID-intolerant and had a history of allergic rhinitis. Skin prick tests showed a strong positive result for dust-mites and for extracts prepared from the ingested flour. Flour samples were also examined microscopically which revealed large numbers of live Dermatophagoides farinae dust-mites. A survey of 57 flour samples showed that 4 samples (7%) were contaminated with dust mites. The findings in the present study confirm that mite-contamination of flour exists in Singaporean households, and it may trigger anaphylaxis in susceptible individuals.

The cross-sectional prevalence of wheeze, rhinitis and eczema in 7,549 randomly selected Singaporean preschoolers aged 4 to 6 years old is reported in this study. Cumulative and past 12 months ('current') prevalence of wheeze was 27.5% and 16.0%, respectively. 'Asthma' was reported by 11.7%. Current rhinitis prevalence was 25.3% and rhinoconjunctivitis, 7.6%. Current chronic rash affected 13.5% of subjects while 9.9% reported chronic rash with flexural distribution. After multivariate analysis, the main risk factors for 'current wheeze' and self-reported asthma, respectively, were family history of allergy (adjusted odds ratio [aOR] 3.22 [2.79-3.71], aOR 3.93 [3.34-4.63]); concurrent rhinoconjunctivitis (aOR 4.04 [3.31-4.92], aOR 3.02 [2.43-3.76]); concurrent chronic flexural rash (aOR 2.56 [2.13-3.08], aOR 2.95 [2.41-3.62]) and previous respiratory infection (aOR 4.80 [4.17-5.53], aOR 3.28 [2.80-3.85]). Thus, these allergy-associated symptoms already affect a considerable portion of children by the preschool years, supporting the need for allergy education and intervention program in this age group.

To study prevalence of allergen sensitization among asthmatics in Thailand, skin prick tests (SPT) were performed in 84 pediatric, 71 adult asthmatics and 71 adult volunteers. Allergen extracts used for testing included common allergens in Thailand and in Singapore. The incidence of positive SPT to any allergen among the three groups (childhood, adult patients and adult controls) were 64.3%, 43.7% and 35.2%, respectively. Dermatophagoides were the most common allergens sensitized by both pediatric (58.3%) and adult asthmatics (40.8%). Twenty-four children (28.6%) and 8 adult patients (11.3%) were sensitized to storage mites (Blomia tropicalis and/or Austroglyciphagus malaysiensis). All patients sensitized to Blomia tropicalis were sensitized to Dermatophagoides. Twenty-seven percent and 15.5% of childhood and adult asthmatics were sensitized to cockroach allergens. The rates of sensitization to oil palm pollen in childhood and adult asthmatics were 8.3% and 5.6%, respectively. Sensitization to other pollens and spores were less than 5%. This study confirms the importance of Dermatophagoides among Thai asthmatics.

Asthma is the most common chronic illness in childhood. This study evaluated the asthma morbidity among Singaporean schoolchildren. The survey involved 1,744 schoolteachers using a structured written questionnaire. 73.4% of class teachers reported at least 1 asthmatic student in their class. 37.1% of teachers had students absent from school for up to 3 days per month and 5.1% missed school for 4 to 14 days in a month. 87.4% of the physical education (PE) teachers reported at least 1 asthmatic student in their class. 65.2% reported an average of 1-3 students sitting out at each PE lesson and 15.1% reported students who were exempted from PE for more than 3 months in a year due to asthma. The morbidity of asthma in Singaporean schoolchildren in terms of school absenteeism and exemption from PE classes is substantial. The data supports a need to improve asthma control amongst our schoolchildren.

This study was aimed to investigate the sensitization pattern to a range of common allergens in young Singaporean children. A cross-sectional study involving 75 children aged below 3 years was carried out. They presented between December 1995 and April 2000 with symptoms of asthma, rhinitis, eczema, or food allergy. Their levels of allergen-specific serum IgE to a panel of foods (egg white, milk, soy protein, shrimp, wheat and peanut), pet dander, dust mites and cockroaches were measured with Pharmacia CAP System radioallergosorbent test kits. Serum IgE levels greater than 0.35 kU/l represented a positive result. Four children could not be tested with the complete panel because of insufficient serum. The prevalence of sensitization was highest for cow's milk (45.9%) followed by egg white (38.7%), dust mites Dermatophagoides pteronyssinus (31.4%) and Blomia tropicalis (25.5%). Sensitization to ingested allergens was significantly more prevalent in children aged 1 year or younger than in the older children (70.4% of those below 1 year, and 50% of those aged 1-3 years; p < 0.02). Sensitization to inhaled allergens, such as dust mites, was more likely to manifest as respiratory symptoms (allergic rhinitis and asthma), while ingested allergens were associated with gastrointestinal symptoms and eczema (p < 0.001). It was concluded that infants and young children are at high risk of sensitization to common environmental substances. Allergen avoidance is therefore important even in the very young. The prevalence of sensitization to food allergens is higher compared to inhalant allergens in young children.

The study of food allergy in Singaporean children is still in its infancy. Confusion and misunderstanding is common among the public. Even so, we have found certain unique features regarding food allergy among Singaporean children. "Bird's nest" has been shown to be the most common cause of anaphylaxis requiring medical attention. This allergen has not been described before. Peanuts and tree nuts are extremely uncommon causes of anaphylaxis, unlike the West. However, the pattern of sensitization to foods in children as shown by skin prick test is similar to other Western populations. The reasons for the difference between the profile foods responsible for anaphylactic reactions in our population and those of the western population, despite the similarity in sensitization profiles, are still unclear.

Blomia tropicalis (Bt) and Dermatophagoides pteronyssinus (Dp) are the predominant domestic mites species in Singapore and Taiwan. This study aims to characterize and compare the mite sensitization profiles in both countries. Skin prick tests were performed on 203 Singaporeans with Dp and Bt crude extracts. In vitro IgE and IgG4 reactivity to extracts and specific allergens (Der p 1, Der p 2 Der p 5 and Blo t 5) were determined by immunoassays. Approximately 91% of the tested Singaporeans were skin test positive for both Bt and Dp. Both populations share similar frequencies of in vitro IgE reactivity to all the allergens tested, but they differ in the pattern and magnitude of allergen sensitization. Although Der p 1, Der p 2 and Blo t5 are major sensitizing allergens in both countries, Blo t 5 is a more potent one in Singapore, probably reflecting the high level of exposure to Bt. The unique major Bt and Dp allergens should be included for precise diagnosis and effective immuno-therapeutic treatment of mite allergy in both countries.

Asthma is a common cause of childhood morbidity. The objective of the present study was to evaluate the factors associated with increased asthma morbidity among asthmatic children in Singapore. A cohort of primary school children (n = 6,404, aged 6-13 years) were evaluated using the American Thoracic Society and the Division of Lung Diseases of the National Heart, Lung and Blood Institute, USA (ATS-DLD) respiratory questionnaire. A total of 2,222 of 6,404 children (34.8%) was found to have reported symptoms of wheezing. Of these, 899/2,222 (40.5%) reported symptoms of "increased asthma morbidity". This was associated with the younger age group, male sex and higher socio-economic status. In addition, concurrent or past allergies were strongly associated with increased asthma morbidity, while premature birth and a history of prior childhood respiratory illnesses and Infections were predictive of greater asthma morbidity. No association was found between increased morbidity and presence of domestic pets, parental smoking, childcare attendance, and the season of birth.

The genetics of asthma and atopy is complex, but can be approached by studies of both candidate genes and mapping of susceptibility loci. Genetic factors conferring susceptibility to disease may vary among ethnic groups. We present our experience with some candidate gene studies for asthma and atopy and susceptibility locus mapping for linkage to chromosome 5q.

Blomia tropicalis is an important triggering factor for allergic diseases such as asthma, rhinitis and atopic dermatitis in tropical and subtropical regions, which climate favours the growth of this species. Our previous mite fauna study revealed that Blomia tropicalis is the most dominant species present in Singapore house dust The main objective of this study is to establish a mass culture of Blomia tropicalis for further characterization of the antigenic and molecular properties of this mite. Approximately one gram of mites could be obtained for every 300-gram of culture medium by culturing under natural condition with a mean annual temperature of 30 degrees C and a mean relative humidity of 80%, and harvested by modified Tullgren funnel. Allergen characterization by IgE immunoblot analysis with crude mite extracts showed some IgE reactivity differences between Blomia tropicalis mite extract from Singapore and Colombia. The possible reasons for these findings are the quality and source of the mite protein extracts used, or selective differences in the population under evaluation. Further, the atopic sera tested showed differences in the pattern and Intensity of IgE immunoblot reactivity to crude extracts of Blomia tropicalis and Dermatophagoides pteronyssinus, the other highly prevalent mite in Singapore. These data support the existence of species-specific allergens. In conclusion, we have been successful in setting up B. tropicalis mass cultures and have prepared extracts of high allergenicity.

This study examined the healthcare utilization patterns for asthma in Singapore, a tropical island city-state, between 1986 and 1993. Asthma was ranked fifth among principal conditions with the highest number of discharges in Singapore (2.4 discharges per 1,000 population per annum). Among the 0-14 year-olds, asthma was ranked second, only after accidents and injuries, as the condition with the highest number of discharges (5.2 per 1,000). It was estimated that there were approximately 20,000 accident and emergency (A & E) room visits for asthma per annum (7.0 visits per 1,000 population per annum). There were, however, no significant changes in the number of hospitalized or emergency room cases for asthma over the period of analysis. In the primary healthcare setting, asthma ranked 6th among the leading conditions seen by the general practitioners and government polyclinics (15 visits per 100 population per annum). Among under 15 year olds, asthma (37 visits per 100 age-adjusted population per annum) ranked as the second leading condition behind upper respiratory tract infections. This study has shown that asthma causes a significant amount of morbidity in the Singapore community.

Skin prick tests done previously revealed a significantly higher percentage of sensitization to an extract of Bipolaris sp. among atopic individuals (34/147, 23.1%) compared to non-atopic individuals. Bipolaris-specific IgE levels were quantified in sera from a representative group of 38 individuals using the Fluorescence Allergosorbent Test (FAST). Result obtained by FAST were found to be comparable to the skin prick test results (r2 = 0.60, p < 0.001 for IgE levels vs wheal sizes; r2 = 0.44, p < 0.001 for IgE levels vs erythema sizes). Characterisation of the extract's allergenic component by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed 28 protein bands with molecular weights (MW) ranging from 11 kDa to above 100 kDa. Immunoblotting with sera of 10 Bipolaris-sensitive (skin prick test, 3 +) individuals showed that Bipolaris spore extract contained at least 4 IgE binding proteins (MW 11-13 kDa, 16-17 kDa, 20-22 kDa and 36 kDa). All 10 sera reacted to the protein at MW 20-22 kDa, 2 sera with MW 11-13 kDa, 3 sera with 16-17 kDa and 6 sera with 36 kDa. This study has thus demonstrated that spores of Bipolaris sp. contain allergenic components which may elicit IgE-mediated reactions.

House dust mite allergens constitute one of the most important allergens in house dust. In this study, the levels of two common dust mite allergens, Der p I and Der f I, in a general hospital in Singapore were evaluated. Our results showed that these allergens were detected in 42/74 (or 57%) of the dust samples. Der p I was found to be the predominant allergen detected (p < 0.001). The allergen levels were, however, low with only 1/74 having a Der p I concentration above 2 micrograms g-1 dust. None of the samples had Der f I concentrations above this level. Of the various niches studied (mattresses, pillows, sofas, carpets, blinds and floors), the blinds and floors had the lowest concentration of allergen (p < 0.05). These low levels in the hospital compared to homes were attributed to the vigorous cleaning schedule in the hospital, the use of plastic to encased mattresses and pillows, vinyl covered sofas and vinyl lined floors. These practices may be adopted in the home as a means to reduce mite allergen exposure.