Adenosine deaminase severe combined immunodeficiency (ADA-SCID) is an autosomal recessive disorder in which a lack of ADA enzyme prevents the maturation of T- and B-cells; early intervention is crucial for restoring immune function in affected neonates. ADA is responsible for purine metabolism and—in its absence—adenosine, deoxyadenosine, and S-adenosylhomocysteine build up and can be detected in the blood. Preparing dried blood spot (DBS) quality control (QC) materials for these analytes is challenging because enrichments are quickly metabolized by the endogenous ADA in normal donor blood. Adding an inhibitor, erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA), has been previously reported to minimize enzyme activity, although this adds additional cost and complexity. We describe an alternative method using unnatural L-enantiomer nucleosides (L-adenosine and L-2′-deoxyadenosine) which eliminates the need for enzyme inhibition. We also present a novel method for characterization of the materials using liquid chromatography mass spectrometry to quantify the analytes of interest.

腺苷脱氨酶严重联合免疫缺陷 (ADA-SCID) 是一种常染色体隐性遗传病，其中缺乏 ADA 酶会阻止 T 细胞和 B 细胞的成熟；早期干预对于恢复受影响新生儿的免疫功能至关重要。ADA 负责嘌呤代谢，如果不存在，腺苷、脱氧腺苷和 S-腺苷高半胱氨酸会积聚并且可以在血液中检测到。为这些分析物制备干血斑 (DBS) 质量控制 (QC) 材料具有挑战性，因为正常供体血液中的内源性 ADA 会快速代谢富集物。之前曾报道过添加抑制剂 erythro-9-(2-hydroxy-3-nonyl) 腺嘌呤 (EHNA) 可将酶活性降至最低，尽管这会增加额外的成本和复杂性。我们描述了一种使用非天然 L-对映异构体核苷（L-腺苷和 L-2'-脱氧腺苷）的替代方法，该方法无需酶抑制。我们还提出了一种使用液相色谱质谱法对材料进行表征的新方法，以量化感兴趣的分析物。