Circulating levels of 25-hydroxyvitamin D and acute cellular rejection in kidney allograft recipients.

BACKGROUND: Vitamin D, in addition to its established role in bone metabolism, may regulate the immune system and affect the outcome of allografts.

METHODS: We identified 351 kidney allograft recipients who had serum levels of 25-hydroxyvitamin D (25[OH]D) measured within the first 30 days of transplantation. We evaluated the relationship between the circulating levels of 25(OH)D and acute cellular rejection (ACR), cytomegalovirus (CMV) disease, BK virus nephropathy, and kidney graft function.

RESULTS: Vitamin D deficiency (circulating levels of 25[OH]D ≤20 ng/mL, defined using The Endocrine Society Clinical Practice 2011 Guideline) was observed in 216 (61.5%) of 351 kidney graft recipients. Vitamin D deficiency was more frequent in female recipients (P=0.007, Fisher exact test) and African American recipients (P<0.001) and was less frequent in preemptive kidney graft recipients (P=0.002). Biopsy-confirmed ACR was more frequent in the vitamin D-deficient group than in the sufficient group (10.2% vs. 3.7%, P=0.04). By multivariable Cox regression analysis, vitamin D deficiency was an independent risk factor for ACR (hazard ratio=3.3, P=0.02). Vitamin D deficiency was not associated with CMV disease, BK virus nephropathy, or kidney allograft function at 1 year. 1,25-Dihydroxyvitamin D3 supplementation initiated within the first 90 days of transplantation was associated with a lesser incidence of ACR compared to no treatment with 1,25-dihydroxyvitamin D3 (5.1% vs. 13.0%, P=0.099).

CONCLUSIONS: Vitamin D deficiency is an independent risk factor for development of ACR within the first year of kidney transplantation and 1,25-dihydroxyvitamin D3 supplementation may help reduce the occurrence of ACR in the vitamin D-deficient group.