Newborn screening (NBS) for severe inborn errors of immunity (IEI), affecting T lymphocytes, and implementing measurements of T cell receptor excision circles (TREC) has been shown to be effective in early diagnosis and improved prognosis of patients with these genetic disorders. Few studies conducted on smaller groups of newborns report results of NBS that also include measurement of kappa-deleting recombination excision circles (KREC) for IEI affecting B lymphocytes. A pilot NBS study utilizing TREC/KREC detection was conducted on 202,908 infants born in 8 regions of Russia over a 14-month period. One hundred thirty-four newborns (0.66‰) were NBS positive after the first test and subsequent retest, 41% of whom were born preterm. After lymphocyte subsets were assessed via flow cytometry, samples of 18 infants (0.09‰) were sent for whole exome sequencing. Confirmed genetic defects were consistent with autosomal recessive agammaglobulinemia in 1/18, severe combined immunodeficiency – in 7/18, 22q11.2DS syndrome – in 4/18, combined immunodeficiency – in 1/18 and trisomy 21 syndrome – in 1/18. Two patients in whom no genetic defect was found met criteria of (severe) combined immunodeficiency with syndromic features. Three patients appeared to have transient lymphopenia. Our findings demonstrate the value of implementing combined TREC/KREC NBS screening and inform the development of policies and guidelines for its integration into routine newborn screening programs.

针对影响 T 淋巴细胞的严重先天性免疫缺陷 (IEI) 的新生儿筛查 (NBS) 以及实施 T 细胞受体切除圈 (TREC) 测量已被证明可以有效地早期诊断并改善患有这些遗传性疾病的患者的预后。对较小的新生儿群体进行的研究很少报告 NBS 的结果，其中还包括对影响 B 淋巴细胞的 IEI 的 kappa 删除重组切除圈 (KREC) 的测量。 NBS 开展了一项利用 TREC/KREC 检测的试点研究，对俄罗斯 8 个地区出生的 202,908 名婴儿进行了 14 个月的研究。 134名新生儿（0.66‰）在第一次检测和随后的复检后呈NBS阳性，其中41%为早产。通过流式细胞术评估淋巴细胞亚群后，18名婴儿（0.09‰）的样本被送去进行全外显子组测序。已确认的遗传缺陷与常染色体隐性无丙种球蛋白血症一致（1/18），严重联合免疫缺陷（7/18），22q11.2DS综合征（4/18），联合免疫缺陷（1/18）和21三体综合征（1/18）。两名未发现遗传缺陷的患者符合具有综合征特征的（严重）联合免疫缺陷的标准。三名患者似乎出现暂时性淋巴细胞减少症。我们的研究结果证明了实施 TREC/KREC NBS 联合筛查的价值，并为制定将其纳入常规新生儿筛查计划的政策和指南提供了信息。