BACKGROUND: Trafficking of
dendritic cell (DC) subtypes to and from the
skin plays a pivotal role in
atopic dermatitis (AD). OBJECTIVES: We sought to determine the CCR pattern of epidermal DC subtypes and CCL expression in relation to the state of AD. METHODS: Shave
biopsy specimens were taken from patients with AD before and after 24 and 72 hours of
atopy patch testing and from the
skin of patients with chronic AD,
skin of patients with
psoriasis, and healthy
skin. CCR expression of epidermal DCs was studied by using
flow cytometry, and
chemokine mRNA levels in the
skin were quantified by
means of
real-time PCR. RESULTS: The total number of
CD1a(+) epidermal DCs increased and the proportion of Langerin-positive
CD1a(+) DCs decreased whereas the percentage of Langerin-negative
CD1a(+) DCs increased after
allergen application. Expression of
CCR5 and
CCR6 of Langerin-negative
CD1a(+) DCs was characteristic for acute AD. Expression of
CCL1,
CCL3,
CCL4, and
CCL11 mRNA was greater in patients with acute AD versus that seen in patients with chronic AD. Only a strong increase of CCLs, in particular
CCL1,
CCL17, and
CCL18, went along with
eczema development, and increased
CCL1,
CCL13,
CCL17 and
CCL18 expression was specific for patients with chronic AD compared with those with
psoriasis. CONCLUSION: Modified recruitment and differentiation of DCs from their
dermal and
blood precursors occurs in the
acute phase of AD. A boost in the amplitude of CCLs after
allergen application goes along with
eczema development.
