We describe the case of a child affected by severe combined immunodeficiency (SCID) with adenosine deaminase (ADA) deficiency showing a maternal T-cell engraftment, a finding that has never been reported before. The presence of engrafted maternal T cells was misleading. Although ADA enzymatic levels were suggestive of ADA-SCID, the child did not present the classical signs of ADA deficiency; therefore, the initial diagnosis was of a conventional SCID. However, ADA toxic metabolites and molecular characterization confirmed this diagnosis. Polyethylene glycol-modified bovine (PEG) ADA therapy progressively decreased the number of maternal engrafted T cells. The child was grafted with full bone marrow from a matched unrelated donor, after a reduced conditioning regimen, and the result was the complete immunological reconstitution.

我们描述了一个患有腺病毒脱氨酶（ADA）缺乏症的严重联合免疫缺陷症（SCID）患儿的病例，该病例显示了母体T细胞的植入，这一发现从未被报道过。植入的母体T细胞的存在是令人误解的。尽管ADA的酶水平提示ADA-SCID，但该儿童并未表现出ADA缺乏的经典体征。因此，最初的诊断是常规的SCID。但是，ADA的有毒代谢产物和分子特征证实了这一诊断。聚乙二醇修饰的牛（PEG）ADA治疗逐渐减少了母体植入T细胞的数量。在减少调节条件后，从匹配的无关亲戚那里给孩子移植了完整的骨髓，结果是完全的免疫重建。