Evidence for increased expression of eotaxin and monocyte chemotactic protein-4 in atopic dermatitis.
BACKGROUND
Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with tissue eosinophilia and the activation of T lymphocytes. The novel eosinophil chemoattractants, eotaxin and monocyte chemotactic protein (MCP)-4, are up-regulated at sites of allergic inflammation, yet their contribution to the pathophysiologic mechanisms of AD remains to be determined.


OBJECTIVE
We sought to investigate the expression of eotaxin and MCP-4 in acute and chronic lesions from patients with AD and to determine their relationship to the numbers of resident inflammatory cells.


METHODS
With use of in situ hybridization, the expression of eotaxin and MCP-4 messenger RNA (mRNA) in skin biopsy specimens from patients with acute and chronic AD skin lesions was compared with that of uninvolved skin from these patients and skin from healthy volunteers.


RESULTS
There was a constitutive expression of eotaxin and MCP-4 mRNA in skin biopsy specimens from healthy subjects. Positive signal for chemokine mRNA was observed both within the epidermis and inflammatory cells (macrophages, eosinophils, and T cells) of the subepidermis in AD skin lesions. Within the subepithelium acute and chronic skin lesions exhibited a significant increase in the numbers of eotaxin and MCP-4 mRNA-positive cells compared with uninvolved skin (P <.01), whereas the numbers of eotaxin and MCP-4 mRNA-positive cells were significantly higher in chronic AD compared with acute AD skin lesions (P <.005, P <.001, respectively). Correlations were observed between the expression of eotaxin and MCP-4 mRNA and the presence of eosinophils and macrophages, respectively, in AD lesions (r(2) = 0.84, r(2) = 0.94).


CONCLUSIONS
There is an increased expression of eotaxin and MCP-4 in acute and chronic lesions, suggesting that these chemotactic factors play a major role in the pathophysiologic mechanisms of AD.
Taha
R A
RA
Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.
Minshall
E M
EM
Leung
D Y
DY
Boguniewicz
M
M
Luster
A
A
Muro
S
S
Toda
M
M
Hamid
Q A
QA
D001706:Biopsy; D054413:Chemokine CCL11; D018925:Chemokines / Q000235:genetics; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil / Q000235:genetics; D016207:Cytokines / Q000235:genetics*; D003876:Dermatitis, Atopic / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D018945:Monocyte Chemoattractant Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000473:pathology
C515456:CCL11 protein, human; C099677:CCL13 protein, human; D054413:Chemokine CCL11; D018925:Chemokines; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil; D016207:Cytokines; D018945:Monocyte Chemoattractant Proteins; D012333:RNA, Messenger