Abstract
Objective: To investigate the changes in peripheral blood 25-hydroxyvitamin D(3)[25-(OH)D(3)], CD4(+)regulatory T (Treg) cells, and Th17 cells in patients with primary biliary cirrhosis (PBC) and their mechanism of action in PBC. Methods: A total of 22 patients with PBC were enrolled and the male/female ratio was 1:21, with a mean age of 61±12 years. There were 7 healthy volunteers matched for age in the normal control group. Electrochemiluminescence immunoassay was used to measure the peripheral blood 25-(OH)D(3)level in the PBC group and normal control group, and flow cytometry was used to analyze the changes in Th17 cells and CD4(+)Treg cells. The t-test, rank sum test, Pearson correlation analysis, or Spearman's rank correlation analysis was used for statistical analysis according to the type of the data. Results: The PBC group had a significantly lower serum 25-(OH)D(3)level than the normal control group (9.49±3.65 vs 27.35±2.35 ng/ml,P< 0.01). Compared with the normal control group, the PBC group had a significantly higher percentage of Th17 cells (2.05%±1.17% vs 0.99%±0.12%,P< 0.01) and a significantly lower percentage of CD4(+)Treg cells (2.54%±1.14% vs 3.78%±0.51%,P< 0.05); there was a significant difference in Th17/Treg ratio between the PBC group and the normal control group (1.00±0.63 vs 0.26±0.02,P< 0.01). In the PBC group, peripheral blood 25-(OH)D3 was not correlated with Th17 cells or Th17/Treg ratio (r= -0.062 and -0.328,P> 0.05), while it was positively correlated with the percentage of CD4(+)Treg cells (r= 0.468,P< 0.05). Conclusion: Patients with PBC have significant reductions in peripheral blood 25-(OH)D(3)and percentage of CD4(+)Treg cells, a significant increase in the percentage of Th17 cells, and immune unbalance of Th17 cells and CD4(+)Treg cells. 25-(OH)D(3)can upregulate the percentage of CD4(+)Treg cells and thus affect the development and progression of PBC, and exogenous vitamin D may improve immune function in PBC patients.