IFN-γ low production capacity in type 1 diabetes mellitus patients at onset of disease

In type 1 diabetes mellitus (T1DM), cytokines can be directly cytotoxic to β-cells, and/or play an indirect role influencing some cells of the immune system. Since several factors could impair cytokine serum levels, the purpose of our study was to longitudi-nally evaluate intracellular cytokines, in T1DM patients, and in subject at risk, by flow cytometry analysis. At T1DM onset we observed significantly lower percentage of peripheral CD4+ and CD8+ cells producing IFN-γ in patients compared to controls and subjects at risk. The 15-month follow-up patients showed significantly lower percentage of CD4+ and CD8+ cells producing IFN-γ compared to the other groups. At 8-year follow-up no significant differences were observed among the groups in the percentage of cells producing cytokines. We could have considered "exhausted cells" or these T cell subsets may be migrated from peripheral blood to pancreas. On the other hand, our results are in agreement with those reported in literature: in animal model the absence of IFN-γ production makes β-cells highly susceptible to viral infection and subsequent attack by natural killer cells, which lead to hyperglycaemia and diabetes mellitus.