Expression of monocyte chemoattractant protein-1 in delayed type hypersensitivity reactions in the skin.
BACKGROUND
Monocyte chemoattractant Protein-1 (MCP-1) is a potent chemotactic factor for monocytes. Because many inflammatory dermatoses are characterized by mononuclear cell infiltrates, it is reasonable to postulate that MCP-1 might be involved in their pathogenesis. To date, no in vivo studies have been published concerning the expression of MCP-1 in this context. The aim of this study was to elucidate the expression of MCP-1 in human inflammatory skin diseases which are thought to involve delayed type hypersensitivity reactions.


METHODS
Expression of MCP-1 was examined in normal skin and three classes of inflammatory skin reactions by immunohistochemistry experiments utilizing a monospecific MCP-1 antiserum. The distribution of monocytes/macrophages and T lymphocytes was determined by immunohistochemistry using antibodies to specific cell surface markers.


RESULTS
Immunostaining with MCP-1 antiserum demonstrated strong MCP-1 expression in lichenoid dermatitis, dermal hypersensitivity reactions, and spongiotic dermatitis. In contrast, normal skin showed minimal MCP-1 expression in the dermis. The cell types displaying MCP-1 expression were endothelial cells of dermal microvessels that were surrounded by lymphocytic infiltrates and monocytes/macrophages at the periphery of the perivascular infiltrates. Occasionally, MCP-1-positive mononuclear cells were present both in the infiltrates and in a diffuse pattern in the surrounding dermis. Keratinocytes were found to produce MCP-1 constitutively in normal skin and in inflamed conditions. The pattern of MCP-1 expression was similar to the pattern observed for monocyte/macrophage distribution, whereas the pattern of MCP-1 expression was different from the pattern of T lymphocyte distribution.


CONCLUSIONS
We observed an enhanced expression of MCP-1 in inflammatory skin conditions. The expression of MCP-1 provides a mechanistic explanation for the increased recruitment of monocytes/macrophages in cell-mediated immune response such as delayed type hypersensitivity reactions in the skin.
Yu
X
X
Department of Oral Biology, Boston University School of Graduate Dentistry, Massachusetts.
Barnhill
R L
RL
Graves
D T
DT
D018932:Chemokine CCL2; D002630:Chemotactic Factors / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D003872:Dermatitis / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000378:metabolism*; D010586:Phagocytes / Q000378:metabolism; D012016:Reference Values; D012867:Skin / Q000276:immunology* / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism
D018932:Chemokine CCL2; D002630:Chemotactic Factors; D016207:Cytokines