Effect of vitamin D levels on the Th17/Treg balance in psoriasis patients and its association with disease severity

HU Liufeng

doi:10.13431/j.cnki.immunol.j.20250082

Abstract：Objective To investigate the effect of vitamin D deficiency on the balance of peripheral blood T helper cell 17(Th 17)and regulatory T cell(Treg)in patients with psoriasis and its relationship with the severity of the disease.Methods A total of 169 patients with psoriasis were selected from June 2020 to June 2023.According to the results of vitamin D measurement,the patients were divided into normal vitamin D group(n=61),vitamin D insufficiency group(n=57),and vitamin D deficiency group(n=51).The percentages of Th17 and Treg cells in peripheral blood were compared among the three groups,and the correlation between vitamin D and Th17/Treg balance was analyzed.COX regression was used to analyze the relationship between vitamin D level and the severity of the disease,followed by a trend test.The restricted cubic spline method was used to explore the dose-response relationship between vitamin D,Th17/Treg and disease severity.The interaction between vitamin D and Th17/Treg on disease severity was analyzed.Results The level of Treg in the serum of patients with psoriasis decreased with the increase of vitamin D level,while the level of Th17 increased with the increase of vitamin D level(P＜0.01).Vitamin D deficiency could lead to the imbalance of Th17/Treg.With the decrease of vitamin D level,the Treg level decreased,while the level of Th17 increased.COX regression analysis showed that after adjusting for confounding factors,vitamin D levels were closely related to disease severity(P＜0.001).Restricted cubic spline model analysis showed that there was a significant nonlinear dose-response relationship of vitamin D and Th17/Treg levels with the severity of disease.With the decrease of vitamin D level,the decrease of Treg level and the increase of Th 17 level,the severity of the disease showed a corresponding increasing trend.Patients with severe psoriasis had the highest proportion given vitamin D deficiency and Th17/Treg imbalance(P＜0.05).At different vitamin D levels,the higher the Th17/Treg ratio,the more significant the increase in the risk of psoriasis,showing a significant interaction[OR(95％CI):3.54(2.45,3.83)](P＜0.05).Conclusion Vitamin D deficiency can lead to the imbalance of Th17/Treg in peripheral blood of patients with psoriasis,thereby aggravating the severity of the disease.