Pharmacogenetics of Asthma Medication in Children: Medication with Anti-inflammatory effects with special focus on Neutrophils.

Asthma is a chronic inflammatory airway disease, which is characterised
physiologically by recurrent airway obstruction that resolves spontaneously or
as a result of treatment. Asthma is the most common chronic disease in
children. Although the etiology of asthma is still not fully clear, there are
effective treatments for asthma. Standard treatment is based on regular use of
inhaled corticosteroids in combination with ß2-agonists, to prevent asthma
exacerbations, retain proper lung function and modulate inflammatory
responses. However, not all patients respond similarly and there is a huge
variation in individual responses to therapy. The response of an individual
patient to a given drug depends on a range of factors, including compliance,
comorbidity, disease severity, environmental factors and genetic background.
Polymorphisms in the genes encoding relevant anti-asthma drug targets can
contribute significantly to this variability.
Pharmacogenetics, focusus on the question of the extent to which the expression
of genetic background is responsible for interindividual variablity in drug
response. Earlier studies on asthma pharmacogenomics have primarily focussed on
adult patients. In this study, pharmacogenetics of asthma medication will be
studied in children for two reasons: (i) Asthma is the most common chronic
disease in childhood and (ii) in children treatment response is not biased by
years of medication use and environmental factors such as smoking.

In the second phase of this study we will focus on inflammatory patterns in
asthma and we aim to identify non-genetic markers for therapy response, with a
focus on inflammatory markers. Airway inflammation is an important hallmark of
asthma. Inflammation in asthma is often described as being 'eosinophilic' based
on the increased presence of primed eosinophils in the airways, though
inflammation in asthmatics may also occur in the absence of eosinophils.
Different types of immune cells are known to respond differently upon asthma
medication in vitro. More knowledge on the different patterns of inflammation
in asthma and the relation with therapy response, may lead to the
identification of predictive inflammatory biomarkers and an improved treatment
of asthmatic patients.

In addition, we are interested in microbiome biomarkers. The microbiome
contains a novel pool of asthma biomarkers. These markers can be obtained
non-invasively, which is important for children.

The overall aim of the project is to define effects of genetic and non-genetic
variants on pharmacological treatment response in children with asthma.

The following questions will be answered:
- What are the characteristics of children who do not respond to
pharmacological treatment?
- Which polymorphisms in genes involved in pharmacological or anti-inflammatory
pathways can be detected?
- Which polymorphisms in genes involved in pharmacological or anti-inflammatory
pathways are associated with treatment response?
- Do children who do not respond to asthma medication have a different type of
airway inflammation than children who respond well to asthma medication?
- are there inflammatory biomarkers that can predict therapy response in
pediatric asthma medication users?
- can we measure the microbiome in children with uncontrolled asthma despite
treatment?

Pharmacogenomics, as well as proteomics and immunophenotyping, will give tools
to characterise and predict treatment response in children with asthma.

The study exists of an invitation of child/parents for interview & inhalation
instruction and DNA collection (saliva sample) and genotyping. During the visit
in the pharmacy, we will also measure the child*s lung function (FVC and FEV1)
with the help of a hand-held diagnostic spirometer (EasyOne). In this way,
simple assessment of lung health is possible in the office setting. This kind
of spirometer meets ATS (American Thoracic Society) recommendation for
diagnostic spirometry. In addition, we will also measure NO (nitrix oxide) in
expiration air with a hand-held analyzer (Niox Mino). This is an easy to use
tool for monitoring (airway) inflammation in asthma patients.A letter to the GP
will be sent to collect additional health information on the children. We will
ask the GP if the child is diagnosed with asthma (yes/no/uncertain) and we will
also ask if there is information from the past 12 months on IgE (in blood) and
lung function tests (spirometry and bronchial hyperresponsiveness).

In phase 2 of this study we will invite a subpopulation for an additional visit
to the Wilhelmina Children's Hospital to perform additional testing. We will
invite children who show good adherence to inhaled corticosteroids, are 8 years
or older and whose parents have given consent to be approached for future
research during phase 1. In addition, we will recruit 10 patients with asthma
(comparable to the non-responders) through the department of Pediatric
Respiratory Medicine. The measurements during this additional visit include:
lung function testing, a questionnaire on asthma for parent and child (digital,
can be performed at home, in advance), measurement volatile and non-volatile
compounds in expiration air, collection of a saliva sample and a venapunction
will be performed (once, 30mL), in order to study inflammatory markers.
Profiles of biomarkers will be compared between poor and good responders (who
will be further stratified on NO levels). It is expected that approximately 180
children will be invited for phase 2 (see study protocol p.17).

We will ask the parents of the 5 last children to be included in the WKZ to
collect a feces sample of their child at home (using an Oragene feces kit) and
complete a questionnaire regarding factors of influence on the microbiome
development (e.g. antibiotics use, way of birth and food intake). These
measurements are non-invasive.

There are no risks associated with participation to this study. Patients are
invited to for an interview, an inhalation instruction and two short lung
function tests in the pharmacy. Furthermore, the patients are asked to donate a
saliva sample.

Concerning phase 2 of the study; risks for the participants are minmial. A
subset of the children will be invited for an additional visit to the
Wilhelmina Children's Hospital to perform additional testing. The measurements
of this additional examination include: lung function testing, a questionnaire
on asthma for parent and child (to be filled in, in advance at home using the
asthma portal), measurement of volatile and non-volatile compounds in
expiration air, and the collection of a saliva sample; these measurements are
non-invasive. Furthermore, blood will be drawn (once, 30 mL). Local anaesthetic
creme or spray will be used to minimize the experience of pain during
venapunction.

Concerning the microbiome measurements there are no risks associated with
participation to this study. The measurements (questionnaire and feces samples
collection) are non-invasive and can be performed at home.