title: Regulatory T cell phenotype and function 4 years after GAD-alum treatment in children with type 1 diabetes.
abstract: Glutamic acid decarboxylase (GAD)(65) formulated with aluminium hydroxide (GAD-alum) was effective in preserving insulin secretion in a Phase II clinical trial in children and adolescents with recent-onset type 1 diabetes. In addition, GAD-alum treated patients increased CD4(+) CD25(hi) forkhead box protein 3(+) (FoxP3(+)) cell numbers in response to in-vitro GAD(65) stimulation. We have carried out a 4-year follow-up study of 59 of the original 70 patients to investigate long-term effects on the frequency and function of regulatory T cells after GAD-alum treatment. Peripheral blood mononuclear cells were stimulated in vitro with GAD65 for 7 days and expression of regulatory T cell markers was measured by flow cytometry. Regulatory T cells (CD4(+) CD25(hi) CD127(lo)) and effector T cells (CD4(+) CD25(-) CD127(+)) were further sorted, expanded and used in suppression assays to assess regulatory T cell function after GAD-alum treatment. GAD-alum-treated patients displayed higher frequencies of in-vitro GAD(65) -induced CD4(+) CD25(+) CD127(+) as well as CD4(+) CD25(hi) CD127(lo) and CD4(+) FoxP3(+) cells compared to placebo. Moreover, GAD(65) stimulation induced a population of CD4(hi) cells consisting mainly of CD25(+) CD127(+) , which was specific of GAD-alum-treated patients (16 of 25 versus one of 25 in placebo). Assessment of suppressive function in expanded regulatory T cells revealed no difference between GAD-alum- and placebo-treated individuals. Regulatory T cell frequency did not correlate with C-peptide secretion throughout the study. In conclusion, GAD-alum treatment induced both GAD(65) -reactive CD25(+) CD127(+) and CD25(hi) CD127(lo) cells, but no difference in regulatory T cell function 4 years after GAD-alum treatment.
authors.affiliation: Division of Pediatrics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Pihl
authors.forename: L
authors.initials: L
authors.lastname: Akerman
authors.forename: S
authors.initials: S
authors.lastname: Axelsson
authors.forename: M
authors.initials: M
authors.lastname: Chéramy
authors.forename: M
authors.initials: M
authors.lastname: Hjorth
authors.forename: R
authors.initials: R
authors.lastname: Mallone
authors.forename: J
authors.initials: J
authors.lastname: Ludvigsson
authors.forename: R
authors.initials: R
authors.lastname: Casas
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000293:Adolescent; D000534:Alum Compounds / Q000008:administration & dosage; D001324:Autoantigens / Q000008:administration & dosage; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000201:enzymology / Q000276:immunology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D005968:Glutamate Decarboxylase / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D007165:Immunosuppression Therapy; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D053699:Interleukin-7 Receptor alpha Subunit / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D016176:T-Lymphocyte Subsets / Q000201:enzymology / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000201:enzymology* / Q000276:immunology*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D001324:Autoantigens; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit; C041524:aluminum sulfate; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2