Psoriatic Arthritis Atopy Study Eindhoven Rotterdam

Psoriasis is a common, non-contagious skin disease with red flaking patches.
Approximately, 1.5% of individuals in western European countries and the US has
this skin disease (point prevalence).
In 5 to 42% of these individuals, arthritis occurs, especially of the smaller
joints of hands and feet. In 68% of cases, this so-called psoriatic arthritis
is preceded by signs of cutaneous psoriasis with a mean period of 10 years. In
14 to 21%, joint symptoms do occur first. Sometimes (15%), both arthritis and
skin psoriasis do present at the same time.

The exact etiology of psoriasis is unknown. Genetics plays an important role.
In those individuals prone to develop cutaneous psoriasis, symptoms can be
provoked by infections, certain drugs, UV-exposure, hormonal influences,
psychological stress, alcohol abuses and smoking.

Recent hypothesis indicate that a dysbalans of regulator T cells is responsible
for the occurrence of psoriasis. Regulator T cells consist of two groups of
cells: Th1-cells involved in the production of the cytokines IL-2, IFN-γ and
IL-12 and Th1-cells associated with the production of IL-4, IL-5 and IL-10.
Psoriasis is assumed to be a example of a Th1-cell mediated disease. Examples
of Th2-cell mediated diseases are asthma, allergic rhinoconjunctivitis, atopic
dermatitis, hand eczema, bullous pemphigoid and HIV-positivity. What pleads for
this hypothesis, is the fact that psoriasis/psoriatic arthritis is seldom seen
in patient who had atopic dermatitis in childhood.

Aim of this study is to explore the relation between Th1-cell mediated diseases
as psoriasis/psoriatic arthritis and Th2-cell mediated asthma, allergic
rhinoconjunctivitis, atopic dermatitis and hand eczema. Question is whether a
dysbalans in regulator T cell population in favor of Th1-cells does protect
against Th2-cell mediated disease.

Prospective study in a group of 700 patients, namely men and women aged 18
years and over with psoriasis, psoriatic arthritis, rheumatoid arthritis
(controls), melanocytic naevi and patients with a phlebological problem who
consult the reumatologist and/or dermatologist.

Both burden of the study and risks associated with participation are extremely
low. Consultations are combined with regular visits to the different
departments involved. Blood testing seldom causes asymptomatic bruises in the
elbow.