22q11.2 deletion syndrome (22q11.2DS) is characterized by a heterogeneous phenotype, including alterations in phospho-calcium metabolism and immunodeficiency. We analyzed vitamin D status and the immune assessment, focusing on T cell subpopulations and dendritic cells (DCs) in a cohort of 17 pediatric 22q11.2DS patients and 17 age-matched healthy subjects. As antigen-presenting cells, DCs are the main target of vitamin D, promoting a tolerogenic T cell response. Patients were subdivided into three groups according to the parameters of phospho-calcium metabolism and serum levels of 25OHD: normal values, vitamin D deficiency and hypoparathyroidism. Different degrees of T cell deficiency, ranging from normal to partial T cell numbers, were observed in the cohort of patients. The group with vitamin D deficiency showed a significant reduction of naive T cells and a significant increase of central memory T cells compared to controls. In this group the number of circulating DCs was significantly reduced. DC decrease affected both myeloid and plasmacytoid DC subsets (mDCs and pDCs), with the most relevant reduction involving pDCs. A direct correlation between 25OHD levels and recent thymic emigrant (RTE) and DC number was identified. Despite the limited cohort analyzed, our results show that deficiency of the pDC subset in patients with 22q11.2DS may be included among the causative factors of the progressive increase of risk of autoimmune diseases in these patients. As most patients suffer from increased susceptibility to infections and heightened prevalence of autoimmune disorders, we suggest a potential role of vitamin D supplementation in preventing autoimmune or proinflammatory diseases in 22q11.2DS.

中文翻译：

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22q11.2缺失综合征的维生素D状况和免疫评估。

22q11.2缺失综合征（22q11.2DS）的特征是异质表型，包括磷酸钙代谢和免疫缺陷的改变。我们分析了一组17名儿科22q11.2DS患者和17名年龄匹配的健康受试者的维生素D状况和免疫评估，重点关注T细胞亚群和树突状细胞（DC）。作为抗原呈递细胞，DCs是维生素D的主要靶标，可促进致耐受性T细胞反应。根据磷酸钙代谢参数和血清25OHD水平将患者分为三组：正常值，维生素D缺乏症和甲状旁腺功能低下。在患者队列中观察到不同程度的T细胞缺乏，范围从正常T细胞到部分T细胞。与对照组相比，维生素D缺乏症组的幼稚T细胞显着减少，而中央记忆T细胞显着增加。在这一组中，循环DC的数量显着减少。DC降低影响髓样和浆细胞样DC子集（mDC和pDC），最相关的降低涉及pDC。确定了25OHD水平与最近的胸腺移民（RTE）和DC数量之间的直接相关性。尽管分析了有限的队列，但我们的结果表明，22q11.2DS患者中pDC亚群的缺乏可能被包括在这些患者中自身免疫疾病风险逐渐增加的病因中。由于大多数患者对感染的敏感性增加，自身免疫性疾病的患病率升高，