Novel NFKB2 Mutation in Early-Onset CVID
Novel NFKB2 Mutation in Early-Onset CVID
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DOI：
10.1007/s10875-014-0064-x
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发表时间：
2014-08-01
影响因子：
9.1
通讯作者：
Ibrahim, Mohammad A. A.
中科院分区：
文献类型：
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作者：
Liu, Yiwen;Hanson, Steven;Ibrahim, Mohammad A. A.
常见变异型免疫缺陷（CVID）在临床、免疫学和遗传学上具有异质性。导致CVID的大多数遗传机制仍然难以捉摸。我们研究了一个非血缘父母的希腊塞浦路斯家庭。两名儿童在很小的时候就被诊断出患有CVID。全外显子测序显示NF KB 2基因C端8bp缺失与疾病相关。该突变导致移码（p.Asp865Valfs*17），从残基865改变17个C-末端氨基酸，并产生一个过早的终止密码子，导致截短的蛋白质，比野生型短19个氨基酸（p100 Delta 19）。我们用染料终止测序和Western blot验证了结果，并证实p100 Delta 19中866处的保守残基从丝氨酸突变为精氨酸，使突变蛋白在这个关键调控位置未磷酸化。因此，NFKB 2/p100加工和核转位被废除。使用流式细胞术，我们进一步证明，与健康对照相比，在NFKB 2/p100 Delta 19的CVID患者中，B细胞（CD 19+）、转换记忆B细胞（CD 27 +IgD-）和T滤泡辅助细胞（Tfh）细胞（CD 4 + CXCR 5+和CD 4 + CXCR 5 Hi）减少。这些数据支持非经典NF κ B B通路在B细胞分化和Tfh细胞发育中起重要作用的观点，并可能为更好地理解CVID的病理学铺平道路。
Common variable immunodeficiency (CVID) is heterogeneous, clinically, immunologically and genetically. The majority of genetic mechanisms leading to CVID remain elusive. We studied a Greek Cypriot family of non-consanguineous parents. Two children were diagnosed with CVID at an early age. Whole exome sequencing revealed 8bp deletion in the C-terminal part of NFKB2 gene associated with disease. The mutation leads to a frameshift (p.Asp865Valfs*17) altering 17 C-terminal amino acids from residue 865, and creating a premature stop-codon resulting in a truncated protein, 19 amino acids shorter than wild type (p100 Delta 19). We validated the results with Dye-termination sequencing and Western blot, and confirmed that the conserved residue at 866 is mutated from serine to arginine in p100 Delta 19, leaving the mutant protein unphosphorylated at this critical regulatory position. Consequently, NFKB2/p100 processing and nuclear translocation were abrogated. Using flow cytometry, we further demonstrated that there was a reduction in B cells (CD19+), switched memory B cells (CD27+IgD-) and T follicular helper (Tfh) cells (both CD4+CXCR5+ and CD4+CXCR5Hi) in a CVID patient with NFKB2/p100 Delta 19, compared to healthy controls. These data support the notion that the non-canonical NF kappa B pathway plays an important role in B cell differentiation and the development of Tfh cells, and may pave the way for better understanding of the pathology of CVID.