Gilmour K C, Cranston T, Loughlin S, Gwyther J, Lester T, Espanol T, Hernandez M, Savoldi G, Davies E G, Abinun M, Kinnon C, Jones A, Gaspar H B
Department of Immunology, Camelia Botnar Laboratories, Great Ormond Street Hospital NHS Trust, Great Ormond Street, London WC1N 3JH, UK.
Br J Haematol. 2001 Mar;112(3):671-6. doi: 10.1046/j.1365-2141.2001.02578.x.
The severe combined immunodeficiencies (SCID) are a heterogeneous group of conditions arising from a variety of molecular defects. The X-linked form of SCID (X-SCID) is caused by defects in the common gamma chain (gammac), and is characterized by a T-B+NK- immunophenotype. This lymphocyte profile is seen in an autosomal recessive form of SCID caused by mutations in the JAK3 molecule. Thus, X-SCID and JAK3-deficient SCID are clinically and immunologically indistinguishable. Knowledge of the precise molecular defect is essential for antenatal diagnosis, carrier testing and for treatment using somatic gene therapy. To identify the molecular defect in children presenting with a T-B+NK- form of SCID, we have developed rapid assays based on flow cytometric analysis of gammac, immunoblotting for JAK3 and gammac, and detection of interleukin-2 (IL-2)-induced tyrosine phosphorylation of JAK3. Sixteen T-B+NK- SCID patients from 15 families were examined. Nine had no detectable gammac, four had abnormal gammac expression and no IL-2-induced JAK3 tyrosine phosphorylation, and one had normal gammac expression but no IL-2-induced JAK3 tyrosine phosphorylation, although JAK3 was present. All these patients had mutations identified in their gammac gene. Two patients exhibited normal gammac expression, but JAK3 was not detected by immunoblotting and these patients were confirmed as having JAK3 gene mutations. Thus, these protein-based assays have led to rapid molecular diagnoses in T-B+ SCID that have subsequently been confirmed by genetic analysis.
重症联合免疫缺陷病（SCID）是一组由多种分子缺陷引起的异质性疾病。X连锁形式的SCID（X-SCID）是由共同γ链（γc）缺陷所致，其特征为T-B+NK-免疫表型。这种淋巴细胞谱也见于由JAK3分子突变引起的常染色体隐性形式的SCID。因此，X-SCID和JAK3缺陷型SCID在临床和免疫学上难以区分。了解精确的分子缺陷对于产前诊断、携带者检测以及使用体细胞基因治疗至关重要。为了确定表现为T-B+NK-形式SCID的儿童的分子缺陷，我们基于γc的流式细胞术分析、JAK3和γc的免疫印迹以及白细胞介素-2（IL-2）诱导的JAK3酪氨酸磷酸化检测开发了快速检测方法。对来自15个家庭的16例T-B+NK- SCID患者进行了检查。9例未检测到γc，4例γc表达异常且无IL-2诱导的JAK3酪氨酸磷酸化，1例γc表达正常但无IL-2诱导的JAK3酪氨酸磷酸化，尽管存在JAK3。所有这些患者的γc基因均发现有突变。2例患者γc表达正常，但免疫印迹未检测到JAK3，这些患者被证实存在JAK3基因突变。因此，这些基于蛋白质的检测方法已导致对T-B+ SCID进行快速分子诊断，随后经基因分析得以证实。
