Early induction of GAD(65)-reactive Th2 response in type 1 diabetic children treated with alum-formulated GAD(65)

• Background We have previously shown that two injections of 20 mu g alum-formulated glutamic acid decarboxylase 65 (GAD(65)) (GAD-alum; Diamyd (R)) in children with recent-onset type 1 diabetes lead to preservation of residual insulin secretion. In vitro cytokine production at the 15 months follow-up indicated immunomodulation. In the present study, we took advantage of peripheral blood mononuclear cells, cryopreserved during early follow-ups, to investigate whether the immunomodulatory effect of GAD-alum was apparent earlier after treatment, preceding the changes previously reported at 15 months.Methods Peripheral blood mononuclear cells from 70 type 1 diabetic children, randomly assigned GAD-alum (n = 35) or placebo (n = 35), that had been frozen at baseline (n = 27) and after 1 (n = 58), 3 (n = 67) and 9 (n = 66) months, were stimulated in vitro with GAD(65), tyrosine phosphatase-like protein IA-2 peptide, insulin peptide, GAD-alum, alum formulation or phytohaemagglutinin. Interleukin (IL)-5, -6, -10, -12, -13, -17, tumour necrosis factor and interferon-gamma were measured in cell supernatants and serum samples using Luminex. Expression of FOXP3 and transforming growth factor-beta was determined by real-time reverse transcription polymerase chain reaction.Results Already 1 month after the first injection, GAD(65)-induced IL-5 and IL-13 together with FOXP3 were enhanced in GAD-alum-treated patients compared to those with placebo. The in vitro response at 3 and 9 months was characterized by a broader range of cytokines in the treated group. Notably, only the T-helper 2-associated cytokines IL-5 and IL-13 together with FOXP3 increased continuously over time.Conclusions Treatment with GAD-alum in type 1 diabetic children induced an early T-helper 2 immune enhanced response to GAD(65), followed by a wider spectrum of cytokines at 3 and 9 months. Copyright (C) 2010 John Wiley & Sons, Ltd.

Nyckelord

GAD65

Immunotherapy

Th1/Th2 Immune Response

Immunomodulation

Cytokines

MEDICINE

MEDICIN

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