Few differences in cytokines between patients newly diagnosed with type 1 diabetes and their healthy siblings.

The cause of the worldwide increase in type 1 diabetes (T1D) is largely unknown. T cells are thought to play a role in disease progression. In contemporary research over the last decade, age- and gender-specific serum levels as well as changes of Th1 and Th2-related cytokines are not well described. From a population-based register of children diagnosed from 1997 to 2005 this study explores eight different cytokines at time of diagnosis. Only TGF-β and IL-18 showed higher levels in patients compared to siblings in an adjusted model (p<0.01); whereas the other seven cytokines were not significantly different. IL-1β, IL-18, IL-12, IL-10 and IL-4 were significantly higher among the youngest children and males had significantly lower levels of IL-10 and IL-12 but higher levels of TNF-α. During the nine-year study all of the cytokines increased except TGF-β, which showed a slight decrease over time. The cytokine levels tended to be highest during summer and were most pronounced for IL-1β and TNF-α. In conclusion, serum levels of known β-cell cytotoxic cytokines were indifferent in patients and siblings, while gender, age and season appear to exert some influence on the serum level and need to be explored further. The influence of time on systemic levels cannot be ignored and may reflect decay or environmental impact on the immune system.