Evaluation of the use of biomarker levels in dried blood spots as a measurement tool for disease severity in patients with atopic dermatitis (AD) and psoriasis.

atopic dermatitis (AD) and psoriasis are common chronic inflammatory skin
diseases with a relapsing and remitting pattern. Promising new treatments for
atopic dermatitis and psoriasis are currently investigated. An important
question will be whether they are more effective than established treatments
such as cyclosporin A. However, comparing the results of (different) clinical
trials is often difficult because of the large number of clinical outcome
measures that are being used.
Many severity measurement tools that are used in clinical trials have
not been validated. A recent review concluded that the EASI and SCORAD are
currently the best validate instruments to assess the severity of AD. The
Psoriasis Area and Severity Index (PASI) are the most widely used clinical
trial efficacy end point for psoriasis. However, intraobserver reliability of
these type of instruments remains unclear and the instruments are time
consuming. Therefore, there is an urgent need for valid, reliable and objective
severity measures that allow comparison of clinical trials and epidemiological
studies.
The discovery of novel cytokines and chemokines generated new potential
biomarkers. A large number of these serum biomarkers have been found to
correlateto disease severity in AD. The most frequently reported serum
biomarkers for AD include serum ECP, serum IgE, serum IL-2R, and serum
TARC/CCL17 levels. Currently, no biomarkers are used for monitoring disease
severity in psoriasis.
The disadvantage of the use of serum biomarkers is the need for a venipuncture.
This is invasive and only possible during admission or control visits. We
therefore want to investigate the levels of a panel of biomarkers, determined
in dried blood spots (DBS). Collection of DBS is a relatively simple and
minimally invasive, nearly painless procedure that can be done by the patients
themselves, at home. We suggest that biomarkers determined in dried blood spots
will replace the currently used serum biomarkers. This will have great
advantages for both daily practice and clinical trials. It offers an objective
measurement tool for disease severity in AD and psoriasis, which will improve
monitoring of patients. Moreover it will decrease the burden of disease,
because less visits to the hospital are necessary.

to investigate whether the levels of a panel of biomarkers in dried blood spots
can be used as a disease severity measurement tool in patients with AD, treated
with topical steroids.

1. Time point 1: visit to the outpatient clinic.
- the researcher explains how to obtain a dried blood spot,
- the patient conducts a small amount of blood by a fingerprick, this is
blotted and dried on filter paper,
- disease severity measurement by POEM / SA-PASI.

2. Time point 2: t=14 days after visit 1.
- the patient conducts a small amount of blood by a fingerprick, this is
blotted and dried on filter paper,
- disease severity measurement by POEM / SA-PASI.


3. Time point 3: During exacerbation.
- the patient conducts a small amount of blood by a fingerprick, this is
blotted and dried on filter paper,
- disease severity measurement by POEM / SA-PASI.

participants will undergo a finger prick in three sessions. Performing a
fingerprick entails a slight risk of haemorrhage and infection. The fingerprick
is comparable to the routinely obtained fingerpricks by diabetic patients at
home.