Intravenous calcitriol therapy restores reduced antigen-induced T-lymphocyte response in 1,25-(OH)(2)D-3-deficient hemodialysis patients

Ten hemodialysis patients were treated with intravenous calcitriol(1-1.5 mu g 3 times per week) for 3 months and parameters reflecting cell-mediated immunity were measured before and at the end of treatment. Peripheral blood CD4+ cells increased from 33.1 +/- 14.2 to 43.8 +/- 5.8% (p < 0.05) causing a comparable increase in CD3+ cells (67.3 +/- 14.3 vs. 77.1 +/- 7.9%, p < 0.05), whereas CD8+ cells did not change significantly (22.2 +/- 5.4 vs. 25.5 +/- 3.0%). Mitogen-induced lymphocyte stimulation responses were normal even before treatment and did not change. Antigen-induced T-cell responses were very heterogeneous before calcitriol therapy; those 5 with initially unmeasurably low serum 1,25-dihydroxyvitamin D-3 (1,25-(OH)(2)D-3) had a weaker response than the other patients (3,873 +/- 1,528 vs. 22,948 +/- 13,684 cpm, p < 0.05). After calcitriol treatment the patients with pretherapy unmeasurably low serum 1,25-(OH)(2)D-3 had a comparable response to other patients (16,220 +/- 9,674 vs. 22,064 +/- 10,331 cpm). Our study shows that calcitriol therapy restores the depressed antigen-induced T-cell response of the hemodialysis patients most deficient in 1,25-(OH)(2)D-3.