Omalizumab treatment can increase the serum levels of vitamin D in patients with chronic spontaneous urticaria

[Objective] To investigate the effect of omalizumab treatment on circulating levels of 25(OH)D in patients with chronic spontaneous urticaria (CSU). [Methods] Thirty-six patients with CSU were treated with 300 mg of omalizumab once every 4 weeks for 3 months. Spearman rank correlation analysis was performed to determine the correlation between UAS7 and 25(OH)D levels before the treatment. UAS7 scores and 25(OH)D levels in patients were compared before and after the treatment, and with those in the controls (36 healthy subjects). [Results] UAS7 was negatively correlated with 25(OH)D levels in peripheral blood of CSU patients before the treatment (r=-0.60, P=0.001). The 25(OH)D levels were significantly higher after the treatment than before the treatment [(27.91±7.37) ng/mL vs. (18.74±6.90) ng/mL, t=5.45, P<0.001]. However, both of them were lower than the normal controls [(35.42±7.83) ng/mL], t=4.19, 9.59, respectively, both P<0.001. After the treatment, UAS7 was significantly lower than that before the treatment [(2.00±3.00) vs. (22.03±5.05), U=20.48, P<0.001]. [Conclusions] Omalizumab treatment can increase the serum 25(OH)D levels in patients with chronic spontaneous urticaria. 25(OH)D may play a protective role in the pathogenesis of chronic spontaneous urticaria.