1,25-Dihydroxyvitamin D in severe immune challenges

1,25 Dihydroxyvitamin D (1,25-D) has been established as an immunoregulatory hormone in vitro, yet there is a paucity of clinical reports supporting this role. Here we are reporting two patients with different acute, severe immune challenges who had undetectable 1,25-D initially, which rose markedly during specific chemotherapy. The present observation suggests that serum 1,25-D could be a measure of immunocompetence, and its administration may be beneficial in acute immune challenges by enhancing the activity of immunoregulatory cells and normal cell differentiation.