CRP and IL-6 concentrations are associated with poor glycemic control despite preserved beta-cell function during the first year after diagnosis of type 1 diabetes.

BACKGROUND: The role of non-specific inflammation in beta-cell loss in type 1 diabetes is unclear. In the present study, inflammatory markers were determined in patients with newly diagnosed disease and related to beta-cell function, glycemic control and autoimmunity.
METHODS: Ninety-seven adult patients with type 1 diabetes mellitus (80% islet antibody positives, ab(+)) were examined at diagnosis and 3, 6, 9 and 12 months after the start of insulin treatment. Plasma C-reactive protein (CRP), interleukin-6 (IL-6), C-peptide, islet autoantibodies, insulin requirement and HbA(1c) were assessed.
RESULTS: The concentrations of CRP were high-normal at diagnosis and did not change during the study period. A positive correlation between CRP at diagnosis and BMI was observed in ab(+) as well as in ab(-) cases. Detectable concentrations of IL-6 were found in 32% (157/485) of the samples and did not change during the study. Ab(-) patients had higher values of CRP at diagnosis and throughout the study compared to the ab(+). Among the ab(+) patients, CRP concentrations during the study were positively correlated to C-peptide at 12 months and an increase in HbA(1c) levels between 6 and 12 months. No associations between the presence or levels of islet autoantibodies and CRP were noted.
CONCLUSIONS: In type 1 diabetes, the islet destructive process and the development of beta-cell remission are not associated with changes in CRP or IL-6. Instead, elevated CRP concentrations are prevalent and seem to reflect insulin resistance, as positive associations to BMI, C-peptide and deterioration of glycemic control were observed. Copyright 2003 John Wiley & Sons, Ltd.