目的:STAT1是在经典JAK/STAT途径中起作用的转导和转录调节因子。除了慢性皮肤粘膜念珠菌病,细菌感染是STAT1功能获得(GOF)突变患者的常见病.这些患者通常表现出B细胞亚群的偏斜;然而,STAT1-GOF突变对B细胞介导的体液免疫的影响仍未被研究.目前还不清楚这些IgG在正常范围内的患者是否需要定期静脉注射免疫球蛋白(IVIG)治疗。
方法:纳入11例患者(携带9种不同的STAT1-GOF突变)。进行报告分析和免疫印迹分析以确认STAT1突变。流式细胞术,深度测序,ELISA,和ELISpot进行评估STAT1-GOF对体液免疫的影响。
结果:所有患者均表现出磷酸化-STAT1和总STAT1蛋白水平升高,两名患者携带新的突变。体外测定显示这两个新的突变是GOF突变。3例总IgG水平正常的患者接受常规IVIG输注,从而有效控制细菌感染。4例显示百日咳毒素特异性抗体的亲和力和特异性受损,伴随着类别转换记忆B细胞的产生减少。患者的免疫球蛋白重链(IGH)库也被破坏,再加上转换的Ig转录本的体细胞超突变频率显着降低。
结论:STAT1-GOF突变破坏B细胞区室和倾斜IGH特征,导致抗体的亲和力和抗原特异性受损和复发性细菌感染。常规IVIG治疗可以控制患者的这些感染,即使是那些总IgG水平正常的人。
OBJECTIVE: STAT1 is a transduction and transcriptional regulator that functions within the classical JAK/STAT pathway. In addition to chronic mucocutaneous candidiasis, bacterial infections are a common occurrence in patients with STAT1 gain-of-function (GOF) mutations. These patients often exhibit skewing of B cell subsets; however, the impact of STAT1-GOF mutations on B cell-mediated humoral immunity remains largely unexplored. It is also unclear whether these patients with IgG within normal range require regular intravenous immunoglobulin (IVIG) therapy.
METHODS: Eleven patients (harboring nine different STAT1-GOF mutations) were enrolled. Reporter assays and immunoblot analyses were performed to confirm STAT1 mutations. Flow cytometry, deep sequencing, ELISA, and ELISpot were conducted to assess the impact of STAT1-GOF on humoral immunity.
RESULTS: All patients exhibited increased levels of phospho-STAT1 and total STAT1 protein, with two patients carrying novel mutations. In vitro assays showed that these two novel mutations were GOF mutations. Three patients with normal total IgG levels received regular IVIG infusions, resulting in effective control of bacterial infections. Four cases showed impaired affinity and specificity of pertussis toxin-specific antibodies, accompanied by reduced generation of class-switched memory B cells. Patients also had a disrupted immunoglobulin heavy chain (IGH) repertoire, coupled with a marked reduction in the somatic hypermutation frequency of switched Ig transcripts.
CONCLUSIONS: STAT1-GOF mutations disrupt B cell compartments and skew IGH characteristics, resulting in impaired affinity and antigen-specificity of antibodies and recurrent bacterial infections. Regular IVIG therapy can control these infections in patients, even those with normal total IgG levels.