异基因造血干细胞移植（allo-HSCT）是治疗多种血液病和遗传性疾病的有效手段，移植后T细胞减少使受者易于发生感染，寻求加速T细胞重建的方法具有重要意义。胸腺上皮细胞（TEC）在T细胞发育中起关键作用，TEC修复为T细胞重建提供了前提条件。IL-22具有促进上皮细胞存活和增殖的作用，并且IL-22具有抑制炎症的作用。研究表明，胸腺内的天然淋巴细胞具有分泌IL-22的潜力，作为一种上皮细胞，TEC的功能是否也受IL-22调节尚不明确。我们的前期研究表明，在受照射损伤的胸腺内，IL-22表达上调与TEC受损密切相关，提示IL-22可能起促进TEC修复的作用，本研究以IL-22为切入点，探索IL-22在TEC修复中的作用以及对T细胞免疫重建的影响。如期完成后有望为allo-HSCT后促进T细胞免疫重建提供新思路。

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is curative for hematologic malignancies and several kinds of hereditary diseases. However, lymphopenia and prolonged recovery of T cells are common complications to allo-HSCT, which expose the patients to opportunistic infections. Accelerating the reconstitution of T-cell immunity should contribute to overcome these complications. Thymic epithelial cells (TEC) play crucial roles in maturation of T cells, and repairing TEC is fundamental for T-cell recovery. IL-22 serves to maintaining the homeostasis of epithelial cells, and IL-22 plays anti-inflammatory role in several kinds of inflammatory diseases. Innate lymphoid cells that reside in the thymus have recently been proved to be potential producer of IL-22. The role of IL-22 on maintaining the homeostasis of TEC is still to be defined. Our previous studies prove that up-regulation of intrathymic IL-22 closely correlates with the impairment to thymus in irradiation treatment settings, which indicate a probable role of IL-22 on thymic regeneration. Therefore, we design this study to explore the roles of IL-22 on the recovery of TEC and T-cell immunity after allo-HSCT in mice. Our study may provide new insights into immune reconstitution after allo-HSCT, and might lead to new strategy in accelerating the reconstitution of T-cell immunity.