Vitamin D supplementation decreases Aspergillus fumigatus specific Th2 responses in CF patients with aspergillus sensitization: a phase one open-label study.

Background: Patients with cystic fibrosis (CF) complicated by allergic bronchopulmonary aspergillosis (ABPA) are vitamin D deficient and in vitro treatment with 1,25 (OH)₂ vitamin D₃ of CD4+ cells from CF patients with ABPA decreases Aspergillus fumigatus(Af)-induced Th2 responses. This Phase I clinical trial investigated the safety and effectiveness of daily vitamin D₃ supplementation in CF patients with ABPA to reduce allergic responses and ABPA symptoms, and increase serum vitamin D levels.

Methods: Seven patients ages 12 years and older with a clinical diagnosis of CF and ABPA with current evidence of Af sensitization received 4000 IU vitamin D₃ (cholecalciferol) daily for 24 weeks. The primary outcome of the study was safety followed by the Aspergillus induced IL-13 response in CD4+ T cells to test the hypothesis that vitamin D supplementation is safe and reduces Aspergillus induced IL-13 responses in CD4+ T cells. Secondary outcomes included total IgE, Aspergillus-specific IgE, vitamin D levels, FEV₁, urinary calcium/creatinine ratio, and cytokine production by Aspergillus-stimulated peripheral blood T cells.

Results: Six months of vitamin D₃ supplementation resulted in significant increases in serum 25-(OH) vitamin D level, and the treatment was well tolerated without evidence of vitamin D toxicity or hypercalcemia. There were no serious adverse events. Daily vitamin D supplementation led to significantly decreased Aspergillus induced IL-13 responses between the baseline visit and that at 24 weeks (p = 0.04). Aspergillus-specific IgE level was also significantly decreased after 8 (p = 0.035) and 24 weeks of daily vitamin D supplementation (p = 0.04).

Conclusions: 4000 IU vitamin D₃ daily over a 24-week period is well tolerated in CF patients with a history ABPA and current evidence of Th2 immunity to Af. . Daily vitamin D supplementation was associated with reduced Aspergillus induced IL-13 responses from peripheral. . CD4+ T cells and Aspergillus-specific IgE levels, as well as increased serum vitamin D levels. This treatment was well tolerated and the study supports further investigation of the use of vitamin D supplementation in Th2 mediated diseases.

Trial registration: This trial was registered at www.clinicaltrials.gov as NCT01222273.