A word of caution is however needed concerning CD28 invalidation as it may alter a number of other immune parameters than the production/differentiation of CD4+CD25+FoxP3+ regulatory T cells and 3) the involvement of NKT cells demonstrated by the absence of diabetes protection in CD1d−/−NOD mice that are deprived of NKT cells [45]. This evidence concerns the gene CD1D and diabetes mellitus.