title: Densities, distribution and phenotypic expression of T cells in human fetal skin.
abstract: T cells are present in normal adult human skin, but their occurrence in fetal skin is unknown. T cell and Langerhans cell (LC) populations were studied using single or double immunohistochemical staining on cryostat-section. Skin samples taken from different body regions of 17 fetuses ranging from 18 to 30 weeks estimated gestational-age (w-EGA), were examined. In all specimens but one, we did not find any epidermal T cell. In contrast, dermal CD3(+) T cells occurred at all w-EGA. The density of these cells increased with increasing age. Double staining showed that CD3(+) T cells were predominantly CD4(+)/CD45RA(+). On the other hand, LC, as assessed by CD1a expression, was evenly distributed within the interfollicular epidermis and papillary dermis at all gestational ages. Analysis of T cell and LC density in different body regions did not show significant topographic differences. We suggest that lack of epidermal T cells, although the LC network was fully represented, might reflect the scarce opportunity of fetal LC to contact foreign antigens in utero.
authors.affiliation: Section of Dermatology, Department of Surgery, University of Parma, Parma, Italy. sergio.dinuzzo@unipr.it
authors.forename: Sergio
authors.initials: S
authors.lastname: Di Nuzzo
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Pavanello
authors.forename: Antonella
authors.initials: A
authors.lastname: Masotti
authors.forename: Giovanna
authors.initials: G
authors.lastname: Giordano
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Panfilis
mesh_terms: D000005:Abdomen / Q000473:pathology; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D020405:Dermis / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D004817:Epidermis / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D005260:Female; D005333:Fetus / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007108:Immune Tolerance; D016130:Immunophenotyping; D007801:Langerhans Cells / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D011247:Pregnancy; D012535:Scalp / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D013909:Thorax / Q000473:pathology; D034941:Upper Extremity / Q000473:pathology
chemical_list: D015703:Antigens, CD