BACKGROUND:BCL10 is a core CBM (CARD-BCL10-MALT1) complex component required for antigen receptor-mediated NF-κB activation. BCL10 deficiency is an exceptionally rare autosomal recessive combined immunodeficiency, with only six patients reported to date. We aimed to characterize the clinical, immunologic, and molecular features of a novel homozygous BCL10 variant and explore mechanisms associated with its leaky phenotype. METHODS:Clinical/immunologic phenotyping, whole-exome and Sanger sequencing, transcript and protein studies, signaling, cytokine, and T cell proliferation assays, and scRNA-seq were performed. RESULTS:A novel homozygous BCL10 c.345_346dup (p.Gly116GlufsTer3) variant was identified in a patient with combined immunodeficiency and immune dysregulation, with relatively mild infections, terminal effector-skewed lymphocytes, and partial Treg preservation. In PBMCs, the variant reduced full-length BCL10 transcripts and BCL10 protein while increasing N-terminal transcripts; HEK293T overexpression showed that the mutant construct could produce a low-abundance truncated protein in vitro. NF-κB signaling was stimulus dependent, with near-absent p-p65 induction in T cells after PMA/ionomycin but relative preservation or enhancement after TNF-α or LPS. T cell proliferation was partially preserved with anti-CD3/CD28 but nearly absent with anti-CD3 alone. ScRNA-seq revealed aberrant Treg-associated gene expression, increased activation/apoptosis/senescence programs in T and NK cells, enhanced inflammatory signaling in B cells and monocytes, and enrichment of AP-1/MAPK, inflammatory NF-κB, and IFN-response pathways. CONCLUSION:This novel linker-region truncating BCL10 variant was associated with leaky combined immunodeficiency with immune dysregulation. Defective CBM-dependent NF-κB activation coexisted with secondary activation of CBM-independent inflammatory and AP-1/MAPK-related programs, suggesting that inflammatory remodeling may contribute to the nonclassical phenotype.

BackgroundSpondyloenchondrodysplasia with immune dysregulation (SPENCD) is a rare autosomal recessive disorder caused by biallelic ACP5 mutations and is characterized by skeletal dysplasia, neurological involvement, and immune dysregulation. According to the latest International Union of Immunological Societies (IUIS) classification, SPENCD is categorized as an inborn error of immunity within the autoinflammatory disorders spectrum; however, targeted therapeutic strategies for immune manifestations remain limited.MethodsWe conducted a multicenter study including five patients from India and from Chongqing and Tianjin, China. Whole-exome sequencing identified six ACP5 variants across the five patients, including four novel variants. The diagnosis of SPENCD was established based on the genetic findings in combination with characteristic clinical features and radiological manifestations. Three patients received treatment with Janus kinase (JAK) inhibitors. In one representative treated patient (Patient 1), immunological parameters before and after treatment were evaluated using flow cytometry and quantitative PCR.ResultsFour novel ACP5 variants were identified in this cohort. All three patients treated with tofacitinib (a JAK inhibitor) showed variable but overall clinical improvement. In one representative patient, immunological changes were observed after treatment, including a reduction in CD21low B cells and changes in T helper cell subsets.ConclusionThis study expands the spectrum of ACP5 mutations and provides clinical and immunological observations suggesting JAK inhibitor therapy may be considered for immune dysregulation in patients with SPENCD.

BackgroundGermline monoallelic gain-of-function (GOF) variants in NFKBIA, encoding IκBα, cause a rare immunodeficiency syndrome classically described as autosomal-dominant anhidrotic ectodermal dysplasia with immunodeficiency. However, the pathogenic spectrum of variants within the N-terminal hotspot and the extent to which distinct alleles converge on shared immunologic phenotypes are not fully defined.MethodsWe studied four unrelated patients with de novo heterozygous NFKBIA variants (p.G33D, p.M37R, p.M37K, p.D31H), including two novel alleles (p.G33D and p.D31H). Clinical and immunological phenotyping, T-cell and B-cell subset analysis, and CFSE-based lymphocyte proliferation assays were performed. Functional consequences were assessed by TNF-α-induced IκBα degradation in patient PBMCs and by NF-κB dual-luciferase reporter assays in HEK293T cells expressing wild-type or mutant IκBα. A comprehensive literature review of all previously reported NFKBIA GOF cases was performed.ResultsClinical severity ranged from recurrent sinopulmonary infections onset in adolescence to severe infantile multisystem disease with bacterial, fungal, and opportunistic infections. All patients exhibited ectodermal abnormalities, and one had autoantibodies. Despite marked clinical heterogeneity, all four patients showed a qualitatively convergent lymphocyte phenotype characterized by expanded naïve T-cell and B-cell compartments and reduced memory and effector subsets. PHA-induced CD4+ and CD8+ T-cell proliferation was preserved in P1 and P3, whereas anti-CD3/CD28-induced T-cell proliferation, assessed only in P3, was impaired, while B-cell proliferation was preserved in the tested patients. Patient PBMCs exhibited markedly delayed or minimal TNF-α-induced IκBα degradation, and all four mutant proteins more strongly suppressed TNF-α-induced NF-κB reporter activity compared to wild-type IκBα. Baseline expression of the IκBα-EGFP fusion proteins was comparable across wild-type and all four mutant constructs.ConclusionThese findings broaden the clinical and genotypic spectrum of N-terminal IκBα GOF disease, identify a consistent immune phenotype characterized by expanded naïve and contracted memory lymphocyte compartments, and support defective regulated IκBα degradation and impaired lymphocyte maturation as shared features of N-terminal IκBα GOF disease.

Background:Management of juvenile idiopathic arthritis (JIA) relies heavily on long-term pharmacotherapy, yet an increasing number of case reports suggest that some drugs may themselves precipitate or worsen the disease. But systematic methods for detecting these safety signals in pediatric cohorts are still lacking. Methods:We screened 10,012,438 reports from the FAERS database using four disproportionality algorithms (ROR, PRR, EBGM, and BCPNN) to identify potential drug and JIA associations. Three complementary machine learning models were developed, including DMPNN, GCN, and SVM, trained on molecular descriptors, chemical fingerprints, and structural graphs to stratify high-risk compounds. Toxicogenomic profiles were generated using ProTox-3.0, and drug-disease target overlap and pathway enrichment were assessed using the CTD and GeneCards databases. External validation relied on our own newly generated transcriptomic data: (i) our newly generated bulk RNA-seq dataset from 47 individuals (39 JIA patients and 8 controls) and (ii) a multi-center single-cell RNA-seq compendium that combined 21 in-house PBMC profiles obtained at four Chinese pediatric hospitals with 9 publicly available systemic juvenile idiopathic arthritis (sJIA) samples. Two of the in-house sJIA patients were sampled longitudinally, before and one month after IL-6-receptor-inhibitor therapy permitting assessment of treatment-induced transcriptomic shifts. Drug-signature activity was quantified with single-sample GSEA for the bulk data and AddModuleScore for the single-cell data. Results:We identified drugs with consistent positive signals across all four FAERS-based disproportionality algorithms. Machine learning models (DMPNN, GCN, SVM) independently confirmed 23 high-risk compounds, with 22 overlapping across all models and predicted risk scores >0.60. Among these, lansoprazole and aripiprazole showed strong signals in both pharmacovigilance and DMPNN predictions. Further toxicogenomic analysis revealed immune toxicity patterns overlapping with JIA-related gene targets and pathways. Notably, bulk RNA-seq and single-cell RNA-seq validation demonstrated that lansoprazole signatures were significantly enriched in monocyte from sJIA patients. This multi-level convergence supports the hypothesis that certain non-antirheumatic drugs may aggravate JIA-like inflammation, particularly within the systemic subtype. Conclusions:In this study, we identify lansoprazole as a likely instigator of systemic juvenile idiopathic arthritis, underscoring that proton-pump inhibitors should be used judiciously in children at autoimmune risk and providing a generalizable playbook for rare-disease pharmacovigilance.

为了探讨湿疹-血小板减少伴免疫缺陷综合征(WAS)的特殊表型.回顾性分析2017年3月重庆医科大学附属儿童医院风湿免疫科收治的1例以单核细胞增多为特征的WAS病例的临床资料及实验室检查结果,并复习相关文献.结果发现,患儿出生后以血小板减少及贫血为主要表现,伴肝脾肿大及间断血便,血常规提示白细胞、中性粒细胞及单核细胞增高,血红蛋白及血小板降低,外周血及骨髓原始幼稚细胞不高,考虑幼年型粒单核细胞白血病(JMML)可能.JMML相关基因和染色体核型未见异常.由于WAS蛋白(WASP)明显表达减少,WAS基因存在一处半合子突变(c.151G＞T,p.V51F),最终确诊为WAS.WAS临床表型变异大.对于早发血小板减少的男婴,建议检测WAS蛋白和WAS基因进行筛查.

Patients with DEX (deficiency in ELF4, X-linked) were recently reported by our team and others, and cases are very limited worldwide. Our knowledge of this new disease is currently preliminary. In this study, we described 5 more cases presenting mainly with oral ulcer, inflammatory bowel disease-like symptoms, fever of unknown origin, anemia, or systemic lupus erythematosus. Whole exome sequencing identified potential pathogenic ELF4 variants in all cases. The pathogenicity of these variants was confirmed by the detection of ELF4 expression in peripheral blood mononuclear cells from patients and utilizing a simple IFN-b luciferase reporter assay, as previously reported. Our findings significantly contribute to the current understanding of DEX.

Monogenic autoinflammatory diseases (mAIDs) are a heterogeneous group of diseases affecting primarily innate immunity, with various genetic causes. Genetic diagnosis of mAIDs can assist in the patient's management and therapy. However, a large number of sporadic and familial cases remain genetically uncharacterized. Deficiency in ELF4, X-linked (DEX) is recently identified as a novel mAID. Here, we described a pediatric patient suffering from recurrent viral and bacterial respiratory infection, refractory oral ulcer, constipation, and arthritis. Whole-exome sequencing found a hemizygous variant in ELF4 (chrX:129205133 A > G, c.691 T > C, p.W231R). Using cells from patient and point mutation mice, we showed mutant cells failed to restrict viral replication effectively and produced more pro-inflammatory cytokines. RNA-seq identified several potential critical antiviral and anti-inflammation genes with decreased expression, and ChIP-qPCR assay suggested mutant ELF4 failed to bind to the promoters of these genes. Thus, we presented the second report of DEX.

BackgroundThe T cell receptor (TCR) diversity is essential for effective T cell immunity. Previous studies showed that TCR diversity in Wiskott–Aldrich Syndrome (WAS) patients was severely impaired, especially in the memory T cell populations. Whether this defect was caused by intrinsic WASp deficiency or extrinsic reasons is still unclear.MethodsWe sorted different T cell subsets from the bone marrow chimeric mice model using both magnetic beads and flow cytometry. TCR repertoires of memory T cells, especially CD4+ effector memory T (TEM) cells and CD8+ central memory T (TCM) cells, were analyzed using the UMI quantitative high-throughput sequencing (HTS).ResultsAn average of 5.51 million sequencing reads of 32 samples was obtained from the Illumina sequencing platform. Bioinformatic analyses showed that compared with wild type (WT), WAS knock out (KO)-CD4+ TEM cells exhibited increased Simpson index and decreased D50 index (P <0.05); The rank abundance curve of KO-CD4+ TEM cells was shorter and steeper than that of WT, and the angle of qD and q in KO-CD4+ TEM cells was lower than that of WT, while these indexes showed few changes between WT and KO chimeric mice in the CD8+TCM population. Therefore, it indicated that the restriction on the TCRVβ repertoires is majorly in KO-CD4+ TEM cells but not KO- CD8+ TCM cells. Principal Component Analysis (PCA), a comprehensive parameter for TCRVβ diversity, successfully segregated CD4+ TEM cells from WT and KO, but failed in CD8+ TCM cells. Among the total sequences of TRB, the usage of TRBV12.2, TRBV30, TRBV31, TRBV4, TRBD1, TRBD2, TRBJ1.1, and TRBJ1.4 showed a significant difference between WT-CD4+ TEM cells and KO-CD4+ TEM cells (P <0.05), while in CD8+ TCM cells, only the usage of TRBV12.2 and TRBV20 showed a substantial difference between WT and KO (P <0.05). No significant differences in the hydrophobicity and sequence length of TCRVβ were found between the WT and KO groups.ConclusionWASp deficiency selectively affected the TCR diversity of different memory T cell subsets, and it had more impact on the TCRVβ diversity of CD4+ TEM cells than CD8+ TCM cells. Moreover, the limitation of TCRVβ diversity of CD4+ TEM cells and CD8+ TCM cells in WAS was not severe but intrinsic.

Abstract Purpose Mutations in TNFAIP3 have recently been recognized as critical cause leading to early-onset autoinflammatory and autoimmune syndrome. And gradually more TNFAIP3 gene mutations were reported, most were frameshift and truncation mutations, and only a few were missense mutations. Here, we reported five Chinese patients manifested with unclassified autoinflammatory syndrome which exhibit two identical novel missense heterozygous variants of uncertain significance (VUS) mutations in TNFAIP3 and verified their pathogenicity. Methods We analyzed the clinical, genetic, and immunological features of five Chinese patients with two novel missense heterozygous VUS in TNFAIP3, and verified their pathogenicity. Results We identified two missense heterozygous mutations ( c.208 G>A, p.Asp70Asn and c.770 T>C, p.Phe257Ser), which were located in the highly conserved residue of amino-terminal ovarian tumor (OTU) domain of TNFAIP3. Only the p.Asp70Asn mutation changes the structure of TNFAIP3 but both variants alter the expression of A20 in peripheral blood mononuclear cells (PBMCs). Accordingly, in vitro TNF-α stimulated patients’ PBMCs showed higher levels of p65 NF-kB phosphorylation and increased IkBα degradation, as well as increased production of the proinflammatory cytokines IL-1β, IL-18 and TNF-a after lipopolysaccharide (LPS) stimulation in vitro Conclusion our data further expands the understanding of the HA20 disease.andhighlights the necessity of functional analysis to evaluate the pathogenicity of VUS in TNFAIP3 for accurate diagnose of HA20.

Multicentric carpo-tarsal osteolysis syndrome (MCTO) is a rare skeletal disorder commonly caused by MAF bZIP transcription factor B (MAFB) mutation. Clinically, it is characterized by aggressive osteolysis, which mainly affects the carpal tarsal bones, and is frequently associated with progressive nephropathy. Since the painful swelling and motion limitation on the wrists and/or ankles of MCTO mimics those of juvenile idiopathic arthritis (JIA), very often, MCTO is misdiagnosed as JIA. Here, we report two MCTO patients initially diagnosed with JIA but showed no response to treatment: P1, with a medical history of more than 10 years, was presented with a typical triad of arthritis-osteolysis-nephropathy; while P2 showed oligoarthritis. Gene tests were then taken and revealed a novel mutation, p.P63Q, and a previously reported conversion, p.S54L, in the MAFB gene. We also summarized the clinical and genetic features of a cohort containing 49 genetically confirmed MCTO patients. All 51 gene-confirmed MCTO cases (49 identified from the literature plus two patients identified herein) developed the disease during childhood. The median delay in diagnosis was 3.83 years (0-35 years). All cases presented bony lesions, and two-thirds had secondary renal lesions (32/48; three unknown), half of which (16/32) progressed into renal failure. Almost two-thirds (34/51), 75% (38/51), and 71% (36/51) of patients had no record of eye problems, facial abnormalities, and other manifestations. Most were misdiagnosed as JIA but didn't respond to treatment. Based on our experience, we suggest that clinicians should comprehensively evaluate the involvement of multiple systems in JIA patients, especially the kidney and eyes. And for JIA patients who underwent more than 3-month treatment with Bio-DMARD, genetic tests are recommended when they show little/no clinical and imaging changes, their high disease activity remains, and their disease activity remission is < 50%, especially when combined with a triad of arthritis-osteolysis-nephropathy.

Objective: To explore the clinical characteristics and risk factors of pediatric patients with Wiskott-Aldrich syndrome (WAS). Methods: This was a case-control study. Clinical data of 165 cases of pediatric patients with WAS, who visited the Department of Rheumatology, Children's Hospital of Chongqing Medical University between January 2007 and August 2020 were retrospectively analyzed and divided into death group and survival group (control group) according to the prognosis in the follow-up. Two independent samples t-test, Welch approximate t-test, Mann-Whitney U test, Pearson χ² test, Yates corrected χ² test, or Fisher exact probability test were used for comparison between groups. Risk factors were analyzed by multivariate Logistic regression analysis. Results: A total of 165 patients with Wiskott-Aldrich syndrome were enrolled in this study, including 40 cases in the death group and 125 cases in the survival group. The WAS score was (4.1±0.8) score in the death group and (3.1±1.2) score in the survival group. The age was 19 (9, 28) months in the death group and 60 (36,86) in the survival group. The episode rates of recurrent infection and (or) severe infection, intracranial hemorrhage and eczema in the death group were significantly higher than those in the survival group (95.0% (38/40) vs.32.0% (40/125),25.0% (10/40) vs. 2.4% (3/125), 90.0% (36/40) vs. 72.0% (90/125), χ²=48.253, 18.325, 5.440, all P<0.05). Infection (22 cases, 55.0%) and intracerebral hemorrhage (15 cases, 37.5%) were the main causes of death, 3 cases (7.5%) died of severe graft-versus-host disease after transplantation. The Logistic regression model indicated that repeated infection and (or) severe infection and non-use of intravenous immunoglobulin (IVIG) replacement therapy were risk factors for death in Chinese WAS patients (OR values were 8.999 and 2.860, 95% CI were (2.041-39.667) and (1.375-5.950), respectively, all P<0.05). Conclusions: Recurrent and (or) severe infection is the main risk factor of death for WAS patietns. Regular IVIG treatment can improve the survival rate of patients with WAS.

CTLA4 deficiency and LRBA deficiency are a group disorders of immune dysregulation that affect CTLA4 pathway. The patients mainly present with autoimmunity, antibody deficiency and recurrent infections. Here we reported three Chinese patients with LRBA and CTLA4 mutations. They all presented with chronic diarrhea, hypokalemia, organomegaly, recurrent infections, and hypogammaglobulinemia. Reduced Treg cells and increased percentage of circulating follicular helper T (cTfh) cells were revealed in these patients. Although steroid and immunoglobulin therapy were given, the enteropathy was persistent. Therefore, abatacept treatment was provided to these patients. They showed a marked improvement of enteropathy and gastrointestinal endoscopy showed alleviated inflammatory lesion and follicular hyperplasia. Furthermore, the frequency of cTfh cells was reduced after abatacept therapy. Taken together, targeted therapy with abatacept is a promising treatment modality for patients with LRBA and CTLA4 deficiency. The findings also suggest that the frequency of cTfh cells could serve as a marker for tracking disease activity and the response to abatacept therapy.

原发性免疫缺陷病(primary immunodeficiency dis-ease,PID)是一组主要由单基因突变导致免疫细胞数量和(或)功能异常的疾病.约1/4的PID患者合并自身免疫性疾病.PID自身免疫的临床表现多样,机制多样,治疗棘手;PID合并自身免疫是疾病预后不良因素.该文总结了最常见的PID自身免疫的临床表现、发病机制和治疗进展,旨在提高临床医师对该类疾病的认识,有助于早期诊治,防止与此有关的累积器官损伤,最终提高PID患者生活质量和预后.

PURPOSE:Signal transducer and activator of transcription 1 (STAT1) is a transcription factor that mediates cellular responses to interferons (IFNs) and other cytokines and growth factors in diverse cell types. STAT1 gain-of-function (GOF) mutations result in an unexpectedly wide range of clinical features. It remains unclear why STAT1 GOF mutations result in such a broad spectrum of phenotypes.METHODS:We analyzed the clinical, molecular, and phenotypic characteristics of nine Chinese patients with STAT1 GOF mutations.RESULTS:This study enrolled nine patients with STAT1 GOF mutations including five novel mutations. We discuss the molecular and phenotypic characterization such as unique Penicillium marneffei lymphadenitis. Patients with STAT1 GOF mutations had defects in both innate and adaptive immunity, including impaired T cell receptor (TCR) diversity; reduced numbers of naïve and effector memory CD4+ T cells, memory B cells, and NK cells; and defects in the production of IL-17A and IFN-γ. In addition, experiments with primary immune cells revealed that enhanced STAT1 phosphorylation resulted from not only lower rates of STAT1 dephosphorylation but also increased total STAT1 expression.CONCLUSIONS:Our report provides the first comprehensive overview of the molecular genetics, clinical heterogeneity, and underlying immunological abnormalities of patients with STAT1 GOF mutations in China. In further study, to find the relationship between different STAT1 GOF mutations and clinical phenotype as well as the mechanism of increased total STAT1 expression will be needed.

Autosomal recessive hyper-immunoglobulin E syndrome (AR-HIES) caused by DOCK8 defects is characterized by recurrent elevated serum IgE level, elevated peripheral eosinophil count, severe atopy, recurrent viral and bacterial infections, and early-onset malignancy. The clinical, genetic, and immunologic characteristics of DOCK8 mutations in Chinese patients have not been characterized in detail. In this research, we screened seven Chinese candidate patients for mutations within the DOCK8 gene and identified three large novel homozygous deletions and four novel point mutations by targeted deep sequencing. The homozygous deletions displayed autosomal recessive inheritance, and the point mutations were sporadic. Absence of DOCK8 protein was confirmed using flow cytometry and western blotting. Besides the typical clinical features and immunologic impairments of DIDS, proliferation of lymphocytes, cytotoxic function of NK cells, and expression of IL-10 in regulatory B cells were severely impaired in DOCK8 mutant patients which may be associated with abnormal immune responses in DIDS. These findings will contribute to the early diagnosis and treatment of DOCK8 patients.

DNA ligase IV (LIG4) deficiency is an extremely rare autosomal recessive primary immunodeficiency disease caused by the LIG4 mutation. To date, fewer than 30 cases of patients have been reported worldwide. No reversion mutations have been previously identified in LIG4. This study enrolled seven Chinese patients with LIG4 deficiency who presented with combined immunodeficiency, microcephaly, and growth retardation. One patient (P1) acquired non-Hodgkin lymphoma. Four patients had impaired T cell proliferation function and skewed T cell receptor diversity. Five novel mutations in LIG4 and a potential hotspot mutation (c.833G>T; p.R278L) in the Chinese population were identified. TA cloning analysis of T cells, NK cells, granulocytes, and oral mucosa cells in P6 revealed wild-type clones and clones that contained both maternally and paternally inherited mutations, indicating possible somatic reversion which need further investigation since no functional or protein assays were possible for all the patients died and no cell lines were available.

目的 探讨1例由11q23染色体CD3E基因突变导致CD3ε缺陷重症联合免疫缺陷病的临床特征及免疫表型.方法 收集近期就诊于重庆医科大学附属儿童医院的1例疑诊CD3ε缺陷致重症联合免疫缺陷病患儿外周血标本,提取外周血单个核细胞(PBMC)及核酸,CDR3扫描谱型技术分析T淋巴细胞受体(TCR)多样性,定量PCR检测TCR重排剪切环(TREC)含量,二代测序筛查免疫相关基因,一代测序验证.结果 TCR Vβ亚家族表现为单克隆或寡克隆峰,提示TCR重组受限;定量PCR未检测到TREC含量提示TCR重组及T细胞胸腺输出严重受损;二代测序显示CD3E基因复合杂合突变,一代测序验证证实.结论 通过临床及免疫学分析、二代测序筛查及一代测序证实,确诊1例CD3E基因复合杂合突变致CD3ε缺陷重症联合免疫缺陷病,该病例罕见且临床与免疫学表型复杂,临床诊断存在困难,导致漏诊与延迟诊断,患者死亡率高且均为早期死亡,干细胞移植或基因治疗是其唯一的根治手段,因此提高临床工作者对本病的认识对于早期诊断与针对性治疗至关重要.

Wiskott-Aldrich syndrome protein (WASp) is a hematopoietic-specific regulator of actin nucleation. Wiskott-Aldrich syndrome (WAS) patients show immunodeficiencies, most of which have been attributed to defective T-cell functions. T follicular helper (Tfh) cells are the major CD4(+) T-cell subset with specialized B-cell helper capabilities. Aberrant Tfh cells activities are involved in immunopathologies such as autoimmunity, immunodeficiencies, and lymphomas. We found that in WAS patients, the number of circulating Tfh cells was significantly reduced due to reduced proliferation and increased apoptosis, and Tfh cells were Th2 and Th17 polarized. The expression of inducible costimulator (ICOS) in circulating Tfh cells was higher in WAS patients than in controls. BCL6 expression was decreased in total CD4(+) T and Tfh cells of WAS patients. Mirroring the results in patients, the frequency of Tfh cells in WAS knockout (KO) mice was decreased, as was the frequency of BCL6(+) Tfh cells, but the frequency of ICOS(+) Tfh cells was increased. Using WAS chimera mice, we found that the number of ICOS(+) Tfh cells was decreased in WAS chimera mice, indicating that the increase in ICOS(+) Tfh cells in WAS KO mice was cell extrinsic. The data from in vivo CD4(+) naive T-cell adoptive transfer mice as well as in vitro coculture of naive B and Tfh cells showed that the defective function of WASp-deficient Tfh cells was T-cell intrinsic. Consistent findings in both WAS patients and WAS KO mice suggested an essential role for WASp in the development and memory response of Tfh cells and that WASp deficiency causes a deficient differentiation defect in Tfh cells by downregulating the transcription level of BCL6.

Mutations in Recombination Activating Genes (RAG1 and RAG2) are common genetic causes of severe combined immunodeficiency (SCID) and Omenn syndrome (OS). The clinical, immunologic, and genetic characteristics of RAG mutations in Chinese patients with SCID or OS have not been studied in detail. In this research, 22 RAG mutations were identified in 15 Chinese patients, including 10 novel mutations in RAG1 (R108X, M630T, E510X, S666P, E669K, C730Y, A857V, K847E, L922PfsX7, and L1025FfsX39) and 4 in RAG2 (R73C, I427GfsX12, P432L, and 311insL). L1025FfsX39 is a potential RAG1 hot-spot mutation in the Chinese population. The distribution of RAG1 mutations rather than mutation type seemed to differ between SCID and OS patients. The thymic output of T lymphocytes, TCR rearrangement, and T cell proliferation were severely impaired in RAG mutant patients. These findings will contribute to the early diagnosis and treatment of SCID and OS to a certain extent.

A spontaneous reversion that restores Wiskott-Aldrich syndrome protein (WASP) expression was reported recently. However, the genetic mechanism underlying the reversion event was unclear. In the present study, a WAS patient with a nonsense mutation (155 C>T, R41X) was followed during a three-year period. No expression of WASP was detected in peripheral blood mononucleated cells (PBMCs) in 2009 and a small population of intracellular WASP positive lymphocytes was detected during the following three years. The increasing trend of the revertant genotype was significant. WASP-expressing cells were present mainly CD56+ NK cells and CD8+ T cells. Sorted WASP+ cells were analyzed, indicating that the population of CD3+ T cells increased from 36.81% to 99.8%. Although the revertant cells in vivo may have a growth advantage, the patient presented a persistent autoimmune disease, thrombocytopenia, and died from extensive pulmonary fibrosis. The results suggest that the clinical consequences of T-cell mosaicism in WAS remain difficult to predict and is not sufficient to fully normalize immune functions in patients with WAS.