Author(s): Karlsson MG, Ludvigsson J
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Abstract At the clinical onset of insulin-dependent diabetes mellitus (type 1 diabetes), inflammation within the pancreatic islets of Langerhans causes insulitis. CD4+ or Th-lymphocytes will be activated after stimulation resulting in interferon-gamma (IFN-gamma) production by Th1-like lymphocytes and/or interleukin-4 (IL-4) secretion from Th2-like lymphocytes. The antigens responsible for this activation are unknown, but studies have suggested glutamic acid decarboxylase (GAD) to be a possible candidate. One peptide from this enzyme (amino acid 247-279) with a similar amino acid sequence to coxsackie B virus may cause lymphocyte proliferation in diabetic patients. In this study we have shown that this peptide activates Th1-like lymphocytes which produce increased amounts of IFN-gamma mRNA, but seldom mRNA for IL-4. Lymphocytes from healthy HLA-matched controls (DR3/4) did not respond with an upregulated mRNA expression for these cytokines when stimulated by the GAD-peptide (P<0.05). A low or absent expression of IFN-gamma mRNA was significantly correlated to a high fasting C-peptide at 3 months' duration (P<0.05). In conclusion, we suggest that GAD65 is involved in the development of type 1 diabetes and that the Th1-response may play a role in the destruction of beta cells.
This article was published in Acta Diabetol
and referenced in Journal of Clinical & Cellular Immunology