This commentary has attempted to describe some of the new aspects of our knowledge
of the immunological properties of 1 alpha,25(OH)2D3, the physiologically active metabolite
of vitamin D3, and its new analogues. These analogues will, in the future, serve as
tools to increase our understanding of the role of vitamin D in immunobiology, not
only in basal research but also, hopefully, in the therapy of immune-mediated diseases.