Mite Allergen Prevention Study

There is an epidemic of allergic disease in childhood, which include asthma, eczema, hayfever and food allergy. The United Kingdom has one of the highest prevalences of allergy, with 1 in 4 persons being affected. In the UK, 5.4 million people are currently receiving treatment for asthma alone, which is associated with >£1 billion in annual healthcare costs.

The pathway to allergic disease starts early in life, and management has so far been directed towards avoidance of triggers, reducing inflammation and relieving symptoms. In order to reduce the prevalence of allergic diseases, we urgently need to find ways of preventing their development. Recently, evidence has emerged that early introduction of peanuts (one of the common food allergens) into the diet of weaning babies at high risk of food allergy helped reduce the risk of peanut allergy.

We therefore hypothesised that giving babies another strong allergen, house dust mite, in the form of oral drops (termed sub-lingual immunotherapy or SLIT) might also help prevent both the development of allergies early on and asthma in mid-childhood.

The Mite Allergen Prevention Study (MAPS) was thus set up, recruiting babies with a strong family history of allergies and treating them from the age of 6 to 18 months with either the house dust mite SLIT or a control solution (normal saline). Our hypothesis were that:

  • MAPS children treated with SLIT would demonstrate less reactivity to either house dust mite or other common allergens over their childhood, as measured by allergy skin prick-tests.
  • MAPS children treated with SLIT would suffer less asthma by mid-childhood.

In parallel to MAPS, other children with a similar high-risk for allergic disease were recruited into the Immune Tolerance in Early Childhood cohort (ITEC). These children did not receive any intervention but were followed up in a similar way to the MAPS children. The aim of this cohort was:

  • To provide additional control cases to be used in the analysis of the MAPS data
  • To help us further understand the risk factors for allergy and asthma within our population.
  • To provide blood samples for analysis, to help determine the genetic, epigenetic and immunological factors at play in early life which lead to allergic diseases.

Mite Allergen Prevention Study

The cohort were recruited before birth, and were first seen at 5-6 months of age. They were recruited from the Isle of White and from Southampton and the surrounding area. The MAPS cohort were then seen every 3 months (9, 12, and 15 months). All children were seen at 18 months, and then again at 3 and 6 years (Fig 1). A total of 111 children were recruited into the MAPS cohort (57 received SLIT and 54 received the control solution) whilst 327 children were recruited into the ITEC study before birth, with 271 of these seen at least once after birth. Follow-up numbers can be found in Fig 2 and Fig 3, and baseline characteristics of the two groups in Table 1 and 2.

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MAPS - Table 2, ITEC Cohort Characteristics at Baseline 78.92 KB 2 downloads

ITEC Cohort Characteristics at Baseline ...
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MAPS - Table 1, Cohort Characteristics at Baseline 79.92 KB 2 downloads

Cohort Characteristics at Baseline ...
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MAPS - Figure 3, ITEC Cohort Follow-Up Details 45.34 KB 2 downloads

ITEC Cohort Follow-Up Details ...
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MAPS - Figure 2, Cohort Follow-Up Details 73.41 KB 2 downloads

MAPS Cohort Follow-Up Details ...
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MAPS - Figure 1, Study Timeline 118.84 KB 3 downloads

Study Timeline from Recruitment to 6 Year Follow-up ...

    Mite Allergen Prevention Study

    Questionnaires were used to gather information from both parents about their allergic status, lifestyle risk factors (e.g. smoking) and home environment. Hospital records were used to gather information on delivery, and a sample of cord blood at birth was taken.

    At all the childhood follow-up visits questionnaires, both study specific and standardised questionnaires (International Study of Asthma and Allergic Diseases in Childhood) were completed by the parents. These extracted information on asthma and allergy status and common environmental exposures. Height and weight were also measured. At all visits allergy skin prick tests were carried out if parents and children consented. At 5 months, 18 months and 6 years blood tests were performed. At six years spirometry with reversibility and exhaled nitric oxide was measured. All participants that demonstrated adequate spirometry technique were invited back for methacholine bronchial challenge. At all ages families who could not attend the centres for a visit were invited to complete the questionnaire over the phone.

    Mite Allergen Prevention Study

    At 18 months of age, at the end of a year of treatment, MAPS children treated with house dust mite SLIT as compared to the saline control had lower rates of sensitization (less positive skin prick tests) to any allergen (16% difference in rates). The intervention was also well tolerated, with no differences between the groups in number and nature of adverse events. At 3 years of age, 18 months after stopping treatment, the children who received SLIT continued to show a trend for less sensitization compared to the control group (11.7% difference), although this difference was no longer as significant. At both of the time-points no difference was seen between the groups in rates of eczema, food allergy or wheezing. These results suggest that administering antigen immunotherapy to high-risk children in early life can help prevent allergic sensitization.

    Data analysis of the follow-up age 6 years is underway and publication is expected shortly. Similarly, publication of initial results from the ITEC cohort (detailed description of the cohort and allergic outcomes at different time-points) is planned imminently. Initial blood samples, from birth and 5 months, of both cohorts are being analysed for immunological, genetic and epigenetic signatures that are associated with later allergic disease.

    Papers published with results from the Mite Allergen Prevention Study can be found by clicking on the links below.

    https://www.ncbi.nlm.nih.gov/pubmed/26073754

    https://www.ncbi.nlm.nih.gov/pubmed/30737992

     

    Mite Allergen Prevention Study

    We are in the process of finalising details of how the data can be accessed and the process of submitting an application to access the data. Please contact Mr Stephen Potter.

    The figures and tables below will give details about what data is available.

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    MAPS - Table 2, ITEC Cohort Characteristics at Baseline 78.92 KB 2 downloads

    ITEC Cohort Characteristics at Baseline ...
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    MAPS - Table 1, Cohort Characteristics at Baseline 79.92 KB 2 downloads

    Cohort Characteristics at Baseline ...
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    MAPS - Figure 3, ITEC Cohort Follow-Up Details 45.34 KB 2 downloads

    ITEC Cohort Follow-Up Details ...
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    MAPS - Figure 2, Cohort Follow-Up Details 73.41 KB 2 downloads

    MAPS Cohort Follow-Up Details ...
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    MAPS - Figure 1, Study Timeline 118.84 KB 3 downloads

    Study Timeline from Recruitment to 6 Year Follow-up ...