Volume 56, Issue 5 pp. 1658-1668
Research Article

Plasmacytoid dendritic cells in inflamed muscle of patients with juvenile dermatomyositis

Consuelo M. López de Padilla

Consuelo M. López de Padilla

Mayo Clinic College of Medicine, Rochester, Minnesota

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Abbe N. Vallejo

Abbe N. Vallejo

Children's Hospital of Pittsburgh, the Cancer Institute, and University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania

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Kelly T. McNallan

Kelly T. McNallan

Mayo Clinic College of Medicine, Rochester, Minnesota

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Richard Vehe

Richard Vehe

University of Minnesota Medical School, Minneapolis

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Stephen A. Smith

Stephen A. Smith

Hennepin County Medical Center, Minneapolis, Minnesota

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Allan B. Dietz

Allan B. Dietz

Mayo Clinic College of Medicine, Rochester, Minnesota

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Stanimir Vuk-Pavlovic

Stanimir Vuk-Pavlovic

Mayo Clinic College of Medicine, Rochester, Minnesota

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Ann M. Reed

Corresponding Author

Ann M. Reed

Mayo Clinic College of Medicine, Rochester, Minnesota

Mayo Clinic, Division of Rheumatology, E15, Departments of Medicine and Pediatrics, 200 First Street SW, Rochester, MN 55905Search for more papers by this author
First published: 27 April 2007
Citations: 109

Abstract

Objective

To examine whether dendritic cells (DCs) are constituents of muscle inflammation in juvenile dermatomyositis (DM).

Methods

The types, numbers, and activation state of DC subsets in inflamed muscle tissue from patients with juvenile DM and in noninflamed muscle tissue from control subjects were examined by multicolor immunofluorescence. Chemokine expression of the muscle-infiltrating cells was examined by laser capture microdissection and quantitative polymerase chain reaction.

Results

Plasmacytoid DCs were the predominant component of the inflamed muscle tissue from patients with juvenile DM. These cells were identified by coexpression of CD4 and CD123, but not CD11c, and also expressed CD83, indicating maturity of the cells. In contrast, in noninflamed muscle, plasmacytoid DCs were scarce and did not express CD83. Mononuclear cells surrounding the blood vessels of inflamed muscle contained abundant transcripts of CCL19 and CCL21, but very little CCL18 transcripts. In contrast, cells from noninflamed muscle contained negligible amounts of CCL19 and CCL21, but had high amounts of CCL18. Both the inflamed and noninflamed muscle tissue had equivalent levels of CXCL12 transcripts, but inflamed muscle contained more transcripts of the CXCL12 receptor CXCR4.

Conclusion

These findings are consistent with the idea that plasmacytoid DCs are mediators of muscle inflammation in juvenile DM. The abundance of CD83+ plasmacytoid DCs in perivascular areas and the overexpression of CCL19 and CCL21 in perivascular cellular foci suggest that in situ activation and maturation of resident plasmacytoid DCs are central to the initiation and perpetuation of muscle inflammation in juvenile DM.

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