The thymus is critical for central tolerance and diverse T-lymphocyte repertoire development, to provide lifelong defense against pathogens while maintaining self-tolerance. Peak thymic output occurs in utero, during infancy, and in early childhood, diminishing throughout life. Infants with congenital heart disease requiring sternotomy often undergo thymectomy to clear the surgical field. The long-term effects of early thymectomy are just being appreciated. Many patients remain asymptomatic despite immunologic findings mirroring those of immunosenescence. Few develop increased infection or lymphoreticular malignancy risk. When considering the effects of infant thymectomy, patients with partial DiGeorge syndrome or hypomorphic recombination-activating gene (RAG) mutations may be instructive. These patients are lymphocytopenic, with increased early-onset infection and autoimmunity risk that is not seen in most patients who underwent thymectomy during infancy. The thymic structure of patients with partial DiGeorge syndrome or hypomorphic RAG is abnormal, with disrupted architecture inclining to perturbation of central tolerance. Similar findings may be seen in patients with myasthenia gravis, although disrupted peripheral tolerance may play a greater role in autoimmunity development. In conclusion, thymectomy during infancy may increase future risk of infection or autoimmunity, with premature immunosenescence mediated through disruption of central and peripheral tolerance mechanisms initiated by early cessation or diminution of thymic output. Ideally, some thymic tissue should be preserved at the time of surgery.

胸腺对于中枢耐受和多样化的T淋巴细胞库发展至关重要，可在保持自我耐受的同时提供对病原体的终生防御。胸腺峰值输出出现在子宫内，婴儿期和儿童早期，一生都在下降。需要进行胸骨切开术的先天性心脏病婴儿经常进行胸腺切除术以清除手术区域。早期胸腺切除术的长期效果才受到赞赏。尽管有免疫学发现与免疫衰老相似，但许多患者仍无症状。很少有人会增加感染或淋巴网状癌的风险。考虑婴儿胸腺切除术的影响时，患有部分DiGeorge综合征或亚型重组激活基因（RAG）的患者突变可能是有益的。这些患者是淋巴细胞减少症，具有较早发作的感染和更高的自身免疫风险，这在婴儿期进行胸腺切除术的大多数患者中是看不到的。部分DiGeorge综合征或亚型RAG患者的胸腺结构这是不正常的，受破坏的架构倾向于干扰中央容忍度。重症肌无力患者可能会发现类似的发现，尽管外周耐受性受损可能在自身免疫发展中起更大作用。总之，在婴儿期进行胸腺切除术可能会增加未来感染或自身免疫的风险，通过早期停止或减少胸腺输出所引起的中枢和外周耐受机制的破坏来介导过早的免疫衰老。理想情况下，在手术时应保留一些胸腺组织。