title: Plasmacytoid dendritic cells represent a major dendritic cell subset in sentinel lymph nodes of melanoma patients and accumulate in metastatic nodes.
abstract: Plasmacytoid dendritic cells (pDC) represent the main source of interferon-alpha, a cytokine with antitumor activity. However, in vitro studies point to pDC as a key subset for induction of tolerance. Herein, we investigated pDC in sentinel lymph nodes (SLN) of melanoma patients. We report that pDC were constantly found in SLN and represented, with Langerhans cells, the most frequent dendritic cell subset. Their frequency in positive (with metastasis) SLN was significantly higher than in negative (without metastasis) SLN. PDC were observed in the T cell-rich areas of lymph nodes, particularly around high endothelial venules and, in metastatic nodes, they accumulated in close vicinity with melanoma nests. Finally, pDC capability to produce interferon-alpha in situ was impaired. Consistently, pDC expressed CD86, but neither CD80 nor CD83, suggesting a not complete activation in melanoma-draining lymph nodes. These results are consistent with the hypothesis of a tolerogenic role played by pDC in tumor immunology.
authors.affiliation: Plastic Surgery Unit - Regional Melanoma Referral Center, Santa Maria Annunziata Hospital, Florence, Italy. g.gerlini@dfc.unifi
authors.forename: Gianni
authors.initials: G
authors.lastname: Gerlini
authors.forename: Carmelo
authors.initials: C
authors.lastname: Urso
authors.forename: Giulia
authors.initials: G
authors.lastname: Mariotti
authors.forename: Paola
authors.initials: P
authors.lastname: Di Gennaro
authors.forename: Domenico
authors.initials: D
authors.lastname: Palli
authors.forename: Paola
authors.initials: P
authors.lastname: Brandani
authors.forename: Adriana
authors.initials: A
authors.lastname: Salvadori
authors.forename: Nicola
authors.initials: N
authors.lastname: Pimpinelli
authors.forename: Umberto Maria
authors.initials: UM
authors.lastname: Reali
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Borgognoni
mesh_terms: D015703:Antigens, CD / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology; D051940:B7-2 Antigen / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology* / Q000473:pathology; D005434:Flow Cytometry; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology; D007150:Immunohistochemistry; D016130:Immunophenotyping; D016898:Interferon-alpha / Q000096:biosynthesis / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology* / Q000473:pathology; D008207:Lymphatic Metastasis; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000276:immunology; D000097802:CD83 Antigen