title: Human peripheral nerve macrophages in normal and pathological conditions.
abstract: We investigated, by immunocytochemistry and immune electron microscopy, the immunophenotype, morphology and functional properties of human peripheral nervous system (PNS) macrophages (M phi) under normal and pathological conditions. Endoneurial M phi disclosed an elongated, ramified morphology, with the main processes oriented along the major axis of nerve fibers; they shared several lineage-related and functional markers with monocyte/macrophages and central nervous system (CNS) microglia, including CD4, CR3, CR4 and FcRIII. In addition, basal expression of HLA-DR antigens was exclusively confined to M phi in normal PNS. In the course of unrelated pathological conditions, resident M phi underwent activation with transformation to hypertrophic cells or foamy phagocytes and up-regulation of the markers expressed in normal conditions; new expression of a macrophagic antigen was detected on activated M phi. In different neuropathies, HLA-DR expression was also detected on non-myelin forming Schwann cells with ultrastructural features indicative of denervation. The present results demonstrate that the human PNS is provided with an intrinsic population of immunocompetent and potentially phagocytic M phi, which represent the peripheral counterpart of CNS microglia.
authors.affiliation: Institute of Neurology, University of Verona, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Bonetti
authors.forename: S
authors.initials: S
authors.lastname: Monaco
authors.forename: C
authors.initials: C
authors.lastname: Giannini
authors.forename: S
authors.initials: S
authors.lastname: Ferrari
authors.forename: G
authors.initials: G
authors.lastname: Zanusso
authors.forename: N
authors.initials: N
authors.lastname: Rizzuto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000943:Antigens, Differentiation / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000276:immunology / Q000502:physiology* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D017933:Peripheral Nervous System / Q000166:cytology* / Q000276:immunology / Q000473:pathology*; D010523:Peripheral Nervous System Diseases / Q000276:immunology / Q000473:pathology*; D010641:Phenotype; D013497:Sural Nerve / Q000473:pathology
chemical_list: D000943:Antigens, Differentiation