title: Altered phenotype and function of dendritic cells in children with type 1 diabetes.
abstract: The importance of dendritic cells (DC) in the activation of T cells and in the maintenance of self-tolerance is well known. We investigated whether alterations in phenotype and function of DC may contribute to the pathogenesis of Type 1 diabetes (T1DM). Mature DC (mDC) from 18 children with T1DM and 10 age-matched healthy children were tested. mDC, derived from peripheral blood monocytes cultured for 6 days in presence of interleukin (IL)-4 and granulocyte-macrophage colony stimulating factor (GM-CSF) and stimulated with lipopolysaccharide (LPS) for the last 24 h, were phenotyped for the expression of the co-stimulatory molecules B7.1 and B7.2. In six patients and six controls allogenic mixed leucocyte reaction (AMLR) was performed using mDC and cord blood-derived naive T cells at a DC/T naive ratio of 1 : 200. Proliferation was assessed on day 7 by [(3)H]-thymidine incorporation assay. Mature DC derived from patients showed, compared with controls, a reduced expression of B7.1 [mean of fluorescence intensity (MFI): 36.2 +/- 14.3 versus 72.9 +/- 34.5; P = 0.004] and B7.2 (MFI: 122.7 +/- 67.5 versus 259.6 +/- 154.1; P = 0.02). We did not find differences in the HLA-DR expression (P = 0.07). Moreover, proliferative response of allogenic naive T cells cultured with mDC was impaired in the patients (13471 +/- 9917.2 versus 40976 +/- 24527.2 cpm, P = 0.04). We also measured IL-10 and IL-12 concentration in the supernatant of DC cultures. Interestingly, we observed in the patients a sevenfold higher level of IL-10 (P = 0.07) and a ninefold lower level of IL-12 (P = 0.01). Our data show a defect in the expression of the co-stimulatory molecules and an impairment of DC priming function, events that might contribute to T1DM pathogenesis.
authors.affiliation: Department of Pediatrics, Tor Vergata University, Rome, Italy. angelini@med.uniroma2.it
authors.forename: F
authors.initials: F
authors.lastname: Angelini
authors.forename: E
authors.initials: E
authors.lastname: Del Duca
authors.forename: S
authors.initials: S
authors.lastname: Piccinini
authors.forename: V
authors.initials: V
authors.lastname: Pacciani
authors.forename: P
authors.initials: P
authors.lastname: Rossi
authors.forename: M L
authors.initials: ML
authors.lastname: Manca Bitti
mesh_terms: D000293:Adolescent; D018122:B7-1 Antigen / Q000378:metabolism; D051940:B7-2 Antigen / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003713:Dendritic Cells / Q000276:immunology*; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D016753:Interleukin-10 / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D017634:Self Tolerance; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D018122:B7-1 Antigen; D051940:B7-2 Antigen; D016753:Interleukin-10; D018664:Interleukin-12