Incrimination of Blomia tropicalis as a Potent Allergen in House Dust and its Role in Allergic Asthma in Kolkata Metropolis, India

Abstract

Background:The increasing trend in allergic diseases has become obvious in the present day, especially in developing countries like India, because of many factors such as change in ambient air quality, increased air pollution, metamorphic change in living habits and lifestyle, and climate.1 Mites present in house dust represent a major source of allergens, resulting in different allergic manifestations all over the world, and hypersensitivity to these dust mites may play a pivotal role in pathogenesis of several allergic complaints including bronchial asthma. The present study evaluated the sensitization toward house dust and house dust mites among patients residing in Kolkata metropolis, India, who are suffering from allergic asthma.Methods:The skin prick test was performed on a total of 1079 patients (585 males and 494 females) between the age group 5–50 years and 50 healthy controls using a variety of 16 common aero-allergenic extracts including 4 allergens of interest, viz. Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis and total house dust allergens. Total serum IgE level was measured by using the EIA technique and specific IgE levels against aforesaid allergens were detected with the Pharmacia ImmunoCAP 100 System. The influence of age and sex, if any, on allergen sensitivity was also investigated. All statistical analyses were performed using SPSS 10.0 for Windows and Zar.2Results:The responses among patients with asthma to house dust and house dust mite allergen tests were as follows: house dust (96.22%), D. pteronyssinus (75.06%), B. tropicalis (72%), and D. farinae (63.72%). The frequency of positive skin response was found to be independent of age and sex. The total serum IgE levels in patients varied between 7.3 and 4040 IU/ml (mean 369 ± 26.51 IU/ml). Specific IgE antibody test proved that 83% patients showed sensitivity toward at least 1 of the allergens tested.Discussion:The results indicate that patients are highly sensitive to house dust and 3 other allergenic mites, namely, D. pteronyssinus, D. farinae, and B. tropicalis, as evidenced by the skin prick test, quantification of total serum IgE, and detection of allergen-specific IgE antibodies among patients of Kolkata. Although mites belonging to the genus Dermatophagoides have already been incriminated as a major source of allergen in house dust in India, this is the first time the role of B. tropicalis mites causing allergic asthma has been reported from an Indian population. Thus, the importance of B. tropicalis mite as an aetiopathological agent in causing various allergic manifestations among the Kolkata population should not be undermined and the allergen should be included in routine allergy testing.

Identification of aero-allergen sensitization in children seeking treatment for bronchial asthma at a tertiary care hospital for children in Sri Lanka

“…We found that 49.3% of children were sensitized to at least one allergen and that the patterns of aeroallergen sensitization was similar to temperate climates, with 37.8% of patients demonstrating sensitization to HDM and 23.7% showing sensitization to cockroach. Similar studies done in South Asia and the South East Asian region show that HDM and cockroach are the two commonest indoor aeroallergens [15,16].…”

Skin prick test sensitisation patterns in children and adults presenting with allergy symptoms in bangalore - a retrospective analysis

“…[13] [12] A study from Bangalore on individuals with asthma showed that 49.28% were sensitive to house dust mites (Der. P and Der.…”

“…F -63.72% senitisations in the same cohort. [12] Although Blomia is reported to be found fairly commonly in Asian homes, older studies have shown high prevalence of sensitisation in Vietnam and Singapore, whereas in rest of Asia Dermatophagoides species were the predominat sensitisers. [4] Immunotherapy is an effective option for HDM allergy and testing for Blomia will enable us to identify and offer specific immunotherapy to individuals suffering from atopic sensitisation to either Dermatophagoides or Blomia variety.…”

“…[5] [12] In Delhi 14.4% of children with asthma showed sensitisation to Aspergillus Tamari. [15] In our cohort, 17.07% of adults were sensitised to aspergillus fumigatus.…”

Clinical Response to Subcutaneous <b><i>Dermatophagoides pteronyssinus</i></b> Immunotherapy in Children with Allergic Rhinitis and Asthma Is Independent of Sensitization to <b><i>Blomia tropicalis</i></b> Allergens

“…However, in the tropical island of Hainan, the southernmost part of China, the predominant species of house dust mites are DP and Blomia tropicalis (BT), both of which have been described in tropical cities [2, 3]. DP and BT have also been shown to be the most common allergen sources causing allergic respiratory diseases in tropical and subtropical regions with prevalence rates in patients affected by asthma and/or rhinitis of 70–90% in India [4], Singapore [5, 6], Taiwan [7] and Hainan in China [8]. These data should be considered in the light of several studies that have demonstrated a low to moderate IgE cross-reactivity between DP and BT [9-12].…”