Abstract:

Luan Hong, Ding Jie, Liu Yihua, Chen Shuangfeng, Zhang Yingxin Department of Dermatology, Liaocheng People′s Hospital, Liaocheng 252000, Shandong, China （Luan H）; Central Laboratory, Liaocheng People′s Hospital, Liaocheng 252000, Shandong, China （Ding J, Liu YH, Chen SF, Zhang YX） Corresponding author: Zhang Yingxin, Email: 912244312@qq.com 【Abstract】 Objective To measure the serum levels of vitamin D, total immunoglobulin E （tIgE）, interleukin-4 （IL-4） and IL-6 in patients with atopic dermatitis （AD）, to evaluate the association between vitamin D and severity of AD, and to investigate the role of vitamin D in inflammatory and immunoregulatory processes during the occurrence of AD. Methods Peripheral blood samples were collected from 37 patients with AD （AD group） and 30 healthy controls （control group）. The serum levels of vitamin D, tIgE, and IL-6 were measured by chemiluminescent sandwich enzyme immunoassay, and those of IL-4 by enzyme-linked immunosorbent assay. The severity of AD was assessed by the SCORing atopic dermatitis （SCORAD） score. The t test or Mann-Whitney U test was performed to assess the differences in vitamin D, tIgE, IL-4 and IL-6 levels between the AD group and control group, chi-square test to compare the proportion of patients with vitamin D deficiency, insufficiency and sufficiency, and Pearson′s correlation analysis or Spearman′s correlation analysis to evaluate the correlations between the SCORAD score and serum levels of vitamin D, tIgE, IL-4 and IL-6. Results Compared with the control group, the AD group showed significantly decreased serum levels of vitamin D （24.77 ± 9.29 vs. 28.98 ± 6.87 μg/L, t = 2.015, P = 0.048）, but significantly increased serum levels of tIgE （137.68 ［37.59 - 414.53］ vs. 45.16 ［14.56 - 112.12］ IU/ml, Z = -3.399, P = 0.001）, IL-4 （8.86 ± 4.83 vs. 4.78 ± 3.07 ng/L, t = 4.147, P < 0.001） and IL-6 （6.53 ［3.99 - 15.30］ vs. 4.58［2.85 - 8.17］ ng/L, Z = -2.173, P = 0.030）. Among patients with AD, the SCORAD score was negatively correlated with serum levels of vitamin D （r = -0.505, P = 0.001）, positively correlated with those of tIgE （r = 0.531, P = 0.001） and IL-4 （r = 0.519, P = 0.001）, but uncorrelated with those of IL-6 （r = -0.139, P = 0.411）. There were significant differences in the proportion of patients with vitamin D deficiency, insufficiency and sufficiency between the AD group and control group （χ2 = 8.762, P = 0.013）. AD patients with vitamin D deficiency showed significantly increased serum levels of tIgE （2846.87 ［319.02 - 7300.00］ IU/ml） and IL-4 （ ［16.37 ± 2.05］ ng/L） compared with those with vitamin D insufficiency （110.07 ［26.20 - 501.48］ IU/ml, P = 0.045; ［8.28 ± 4.48］ ng/L, P = 0.011） and those with vitamin D sufficiency （123.93 ［91.61 - 273.68］ IU/ml, P = 0.024; ［8.00 ± 4.63］ ng/L, P = 0.041）. In addition, serum levels of IL-6 were also higher in patients with vitamin D deficiency than in those with vitamin D sufficiency （15.10 ［8.49 - 30.72］ vs. 6.22 ［4.47 - 9.47］ ng/L, P = 0.011］. Conclusions Vitamin D deficiency or insufficiency exists in patients with AD. Vitamin D deficiency is correlated with high serum levels of tIgE, IL-4 and IL-6, and the severity of AD is closely correlated with increased serum levels of tIgE and IL-6 as well as decreased serum levels of vitamin D.