title: Reduced frequency of peripheral plasmacytoid dendritic cells in type 1 diabetes.
abstract: Dendritic cells (DCs) as antigen presenting cells play an important role in the initiation of an autoimmune disease like type 1 diabetes. Although there is evidence from the NOD mouse model that the function and frequency of DCs is altered in type 1 diabetes, there is little data on dendritic cells in human type 1 diabetes. We investigated peripheral blood myeloid (mDC1 and mDC2) and plasmacytoid dendritic cells (pDCs) in 15 type 1 diabetes patients with recent onset (within the last 3 months) of type 1 diabetes as well as in 15 patients with long standing (more than 5 years) type 1 diabetes by flow cytometry. Both groups were compared to age matched controls. We observed a significantly reduced percentage of pDCs of peripheral blood mononuclear cells (PBMCs) in both recent onset (0.13 vs. 0.25%, p=0.01) and long standing type 1 diabetes patients (0.13 vs. 0.24%, p=0.01). The absolute counts of pDCs per ml of blood were also significantly lower in both recent onset (mean 9560 vs. 13524, p=0.048) and long-standing diabetes (mean 7869 vs. 12202; p=0.05). The percentage of mDC1 was significantly diminished in recent onset (0.21% vs. 0.30%, p=0.034), but not in long standing type 1 diabetes. Our study demonstrates a persisting reduction of peripheral plasmacytoid DCs in type 1 diabetes patients. Since pDCs are involved in the control of immune responses and inducing regulatory cells, a reduced number of pDCs may predispose to an autoimmune reaction in the pancreatic islets.
authors.affiliation: Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Hinkmann
authors.forename: I
authors.initials: I
authors.lastname: Knerr
authors.forename: E-G
authors.initials: EG
authors.lastname: Hahn
authors.forename: T
authors.initials: T
authors.lastname: Lohmann
authors.forename: C C
authors.initials: CC
authors.lastname: Seifarth
mesh_terms: D000293:Adolescent; D000328:Adult; D015551:Autoimmunity; D002452:Cell Count; D002648:Child; D003713:Dendritic Cells / Q000276:immunology / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013997:Time Factors
chemical_list: D006442:Glycated Hemoglobin