cqvip:Background: There have been only two reports on immunophenotypic characteriza tion in the cutaneous lesions of dermatomyositis (DM) that emphasize the importa nce of the infiltrating CD4+ T lymphocytes. Objectives: To characterize the imm unophenotype of the cells that infiltrate the lesional skin of DM and to evaluat e the possible T-helper (Th) polarization Th1/Th2 through detection of specifi c cytokines, chemokine receptors and markers of cellular activation. Methods: Sk in biopsy specimens derived from pathognomonic lesions (Gottron’s papules and Gottron’s sign) of eight patients withDMwere immunostainedwith a large panel o fmonoclonal antibodies to CD3, CD4, CD8, myeloperoxidase(MPO), eosinophil cation ic protein, tryptase, CD40, CD40 ligand (CD40L), HLA-DR, interleukin (IL)- 2, IL- 4, IL- 5, IL- 13, interferon-γ , tumour necrosis factor-α , recept or 3 for CXC chemokines (CXCR3) and receptor 3 for CC chemokines, using the alka line phosphatase-antialkaline phosphatase method. Control specimens were obtai ned from five healthy subjects and from six patients with discoid lupus erythema tosus. Results: Activated CD4+ Th lymphocytes (HLA-DR+ CD40L+ ) were the principal infiltrating cells in the lesional skin of DM; the CD4/CD8 ratio was a pproximately 2· 5. A mixed Th1/Th2 profile and higher Th1 cytokine production t ogether with significant staining for CXCR3 were detected. Neutrophil granulocyt es were the second most abundant population; eosinophil granulocytes were very p oorly represented. Conclusions: Activated CD4+ T cells presumably mediate the main pathogenetic mechanisms in pathognomonic skin lesions. The interaction betw een CD40 andCD40L could be an important mecha nismof cellular activation in cutaneous immune-mediated inflammation by ind uction of secretion of proinflammatory cytokines and chemokines. Neither Th1 nor Th2 clear polarization was found, although there was a slight Th1 prevalence. T here was a significant quantity of MPO+ cells (neutrophil granulocytes) in the in-flamed tissue, and they might have a role in sustaining the chronic inflam mation.
展开▼
