Study of n-Acetyltransferase-1 en -2 (NAT-1, NAT-2) and other polymorphisms in persons with contactallergy for p-Phenylenediamine (PPD)

There are indications that the growing use of hair-dye and henna-tattoos is
associated with an increase of the number of people with a contact-allergy to
the substance of p-Phenylenediamine (PPD), a component of hair-dye. Every
individual possesses the enzymes n-Acetyltransferase-1 (NAT-1) and
n-Acetyltransferase-2 (NAT-2). NAT-1 and -2 are involved in transforming PPD.
In the general population however, there are different genetically determined
differences in the structure of NAT-1 and NAT-2. In some individuals NAT-1 and
NAT-2 operate fast (fast acetylators) and in others slowly (slow acetylators),
mixed-variants also exist.
Patients with eczematous skin reactions and a suspicion of contact-allergy are
routinely being tested in the department of Dermatology by means of a patch
test. In the standard patch test people are tested on a series of frequent
allergens (the European Standard series). This standard series also contains
the allergen PPD. Today about 2 to 3 % of all tested patients in Europe have a
contact-allergy to PPD. Skin reactions in PPD-allergy can be severe.
There are signs that the acetylatorstatus (the slow variant in particular) is
associated with a higher risk of developing a PPD-contact-allergy. Previous
studies however have been performed in relatively small series, in which the
clinical relevance of the reaction on PPD hasn*t been well characterized. To be
able to respond more adequately to the question of the role of acetylatorstatus
in PPD-allergy, it is desirable to know how the distribution is between *slow*
versus *fast* and mixed-variants in a well-documented case-series of
dermatological patients with PPD-allergy.
In studies of other T-cell mediated reactions indications have been found that
polymorfisms in genes that code for certain cytokines (e.g. TNF-α, MnSOD and
Inteleukine 1-β) are involved in the severity of the immunological defence
reactions on exogenous substances.

Determine the number of variants of NAT-1 and NAT-2 in patients with
contact-allergy to PPD.
Exploring polymorfisms in genes that are involved in the production and
regulation of cytokines that modulate immunological defence reactions.

In this study a small amount (10 ml) of blood is needed from patients with
PPD-allergy. Each patient that has a positive reaction on PPD or the chemically
closely related p-Toluenediamine (PTD) in the routinely taken patch-test at the
department of Dermatology in the University Medical Centre Groningen (UMCG) are
asked if they are prepared to give a blood sample for this study. When
permission is given, blood will be taken in the laboratory of the UMCG and will
then be frozen for storage and processing.
The stored blood samples are made anonymous and only with a code it can be
traced back to the specific patientfile. The key of the code is in the
possession of the main investigator prof. P.J. Coenraads.
To achieve a large enough case-series, considered the amount of patients that
have a positive reactions to PPD, the collection of blood samples will take a
minimum of 4 years. According to the power-calculation 400 blood samples from
PPD-allergic patients will be needed. To realise this number, cooperation has
been obtained from the Dermatology departments of the University Medical centre
St. Radboud in Nijmegen and the Vrije Universiteit Medical Centre in Amsterdam.
Processing and analysis of the anonymous blood samples will take place in
cooperation with the department of Toxicology/Ecotoxicology from the University
of Trier (Germany) as described in the manuscript from Blömeke et al.

All patients that are considered for participating in this study because of the
results of the allergy-test will be informed verbally. Subsequently the patient
will receive written information signed by the investigator and an independent
physician, in which the objective and design is further explained. Verbally as
well as in writing the patient will be explicitly told that he can quit
participating in the study, without this having any negative influence on the
treatment of the patient in the UMCG. When a patient decides to participate in
the study, written informed consent will be asked by signing the informed
consent form both by the patient and the investigator. The effort of patients
will be kept to a minimum. Blood will be taken by experienced and qualified
employees from the laboratory of the UMCG. The investment in time will be about
5 to 10 minutes per patient and will only include giving a blood sample. It
will not be necessary to fill in questionnaires or any other forms.