Calcitriol (1,25-dihydroxy-vitamin D3) coadministered with influenza vaccine does not enhance humoral immunity in human volunteers

Calcitriol, also known as 1,25-dihyrody-vitamin D3, is a steroid hormone that has been shown to have effects on cytokine production and lymphocyte proliferation. Coadministration of calcitriol with trivalent influenza vaccine in mice enhanced both mucosal and sytemic antibody responses. We studied the effects of calcitriol coadministered with a commercially available influenza vaccine: in 175 human volunteers in this double-blind, placebo controlled clinical trial. Subjects that received calcitriol experienced more pain at the injection site compared with placebo recipients. No significant differences in hemagglutination inhibition titers against MINI, H3N2, or influenza B antigens were detected at 1 or 3 months postvaccination. We conclude that coadministration of 1.0 mu g of calcitriol at a site adjacent to influenza vaccination does not enhance humoral immunity in human volunteers (C) 1999 Elsevier Science Ltd. All rights reserved.