A dominant autoinflammatory disease caused by non-cleavable variants of RIPK1.

Activation of RIPK1 controls TNF-mediated apoptosis, necroptosis and inflammatory pathways1. Cleavage of human and mouse RIPK1 after residues D324 and D325, respectively, by caspase-8 separates the RIPK1 kinase domain from the intermediate and death domains. The D325A mutation in mouse RIPK1 leads to embryonic lethality during mouse development2,3. However, the functional importance of blocking caspase-8-mediated cleavage of RIPK1 on RIPK1 activation in humans is unknown. Here we identify two families with variants in RIPK1 (D324V and D324H) that lead to distinct symptoms of recurrent fevers and lymphadenopathy in an autosomal-dominant manner. Impaired cleavage of RIPK1 D324 variants by caspase-8 sensitized patients' peripheral blood mononuclear cells to RIPK1 activation, apoptosis and necroptosis induced by TNF. The patients showed strong RIPK1-dependent activation of inflammatory signalling pathways and overproduction of inflammatory cytokines and chemokines compared with unaffected controls. Furthermore, we show that expression of the RIPK1 mutants D325V or D325H in mouse embryonic fibroblasts confers not only increased sensitivity to RIPK1 activation-mediated apoptosis and necroptosis, but also induction of pro-inflammatory cytokines such as IL-6 and TNF. By contrast, patient-derived fibroblasts showed reduced expression of RIPK1 and downregulated production of reactive oxygen species, resulting in resistance to necroptosis and ferroptosis. Together, these data suggest that human non-cleavable RIPK1 variants promote activation of RIPK1, and lead to an autoinflammatory disease characterized by hypersensitivity to apoptosis and necroptosis and increased inflammatory response in peripheral blood mononuclear cells, as well as a compensatory mechanism to protect against several pro-death stimuli in fibroblasts.

Phenotypic and Immunological Characterization of Patients with Activated PI3Kδ Syndrome 1 Presenting with Autoimmunity.

PURPOSE: Autoimmunity is a significant feature of APDS1 patients. We aimed to explore the pathogenic immune phenotype and possible mechanisms of autoimmunity in APDS1 patients. METHODS: The clinical records and laboratory data of 42 APDS1 patients were reviewed. Immunophenotypes were evaluated by multiparametric flow cytometry. Autoantibodies were detected via antigen microarray analysis. RESULTS: A total of 42 children with PIK3CD gene mutations were enrolled. Immunological tests revealed increased proportions of effector memory cells (86%) and central memory cells (59%) among CD4+ T cells; increased proportions of effector memory cells (83%) and terminally differentiated effector memory T cells (38%) among CD8+ T cells. Fewer CD3+ T cells and B cells and higher IgG levels were reported in patients with autoimmunity. The proportion of Tregs was decreased, and the proportions of Th9, Tfh, and Tfr cells were increased in APDS1 patients. Among APDS1 patients, higher proportion of Th2 and Tfr cells were found in those with autoimmunity. The proportions of CD11c+ B and CD21lo B cells in patients with autoimmunity were significantly increased. Antigen microarray analysis revealed a wide range of IgG/IgM autoantibodies in patients with APDS1. In patients with autoimmunity, the proportion of Tfr might be positively correlated with autoantibodies. CONCLUSIONS: The pathogenic immune phenotype of APDS1 patients included (1) deceased CD3+ T-cell and B-cell counts and increased IgG levels in patients with autoimmunity, (2) an imbalanced T helper cell subset, (3) increased proportions of autoreactive B cells, and (4) distinct autoantibody reactivities in patients with autoimmunity.

Novel Mutation in the Moesin (MSN) Gene Leads to Immunodeficiency with Epstein-Barr Virus (EBV) Infection and Dermatomyositis-Like Symptoms.

PURPOSE: Moesin (MSN) deficiency is a recently reported combined immunodeficiency, and few cases have been reported to date. We describe a Chinese patient with a novel mutation causing MSN deficiency and a novel phenotype. METHODS: Clinical and immunological data were collected. Whole-exome sequencing was performed to identify gene mutations. MSN protein expression and T cell proliferation and activation were determined by flow cytometry. Cell migration was confirmed with a Transwell assay. Autoantibody levels were analyzed using antigen microarrays. RESULTS: The patient was a 10-year-old boy who presented with recurrent fever, oral ulcers and dermatomyositis-like symptoms, such as periorbital edema, facial swelling, elevated creatine kinase levels, and abnormal electromyography and muscle biopsy results. Epstein-Barr virus (EBV) DNA was detected in the serum, cells and tissues of this patient. He further developed nasal-type NK/T-cell lymphoma. A novel hemizygous mutation (c.68 A > G, p.N23S) in the MSN gene was found. The immunological phenotype of this patient included persistent decreases in T and B lymphocyte counts but normal immunoglobulin IgG levels. The patient had attenuated MSN protein expression and impaired T-cell proliferation and migration. The proportions of Tfh cells and CD21low B cells in the patient were higher than those in the controls. Moreover, 82 IgG and 102 IgM autoantibodies were more abundant in the patient than in the healthy controls. CONCLUSIONS: The novel mutation N23S is pathogenic and leads to a severe clinical phenotype. EBV infection, tumor, and dermatomyositis-like autoimmune symptoms may be associated with MSN deficiency, further expanding the understanding of the disease.

Novel Compound Heterozygous Variants in the FAS Gene Lead to Fetal Onset of Autoimmune Lymphoproliferative Syndrome (ALPS).

OBJECTIVE: FAS gene defects lead to autoimmune lymphoproliferative syndrome (ALPS), which is often inherited in an autosomal dominant and rarely in an autosomal recessive manner. We report a case of a newborn girl with novel compound heterozygous variants in FAS and reveal the underlying mechanism. METHODS: Whole-exome sequencing (WES) was used to identify pathogenic variants. Multiparametric flow cytometry analysis, phosflow analysis, and FAS-induced apoptosis assays were used to explore the effects of the variants on FAS expression, apoptosis, and immunophenotype. The HEK293T cells were used to assess the impact of the variants on protein expression and FAS-induced apoptosis. RESULTS: The patient was born with hepatosplenomegaly, anemia, and thrombocytopenia. She also experienced COVID-19, rotavirus infection, herpes simplex virus infection, and severe pneumonia. The proportion of double-negative T cells (DNTs) was significantly elevated. Novel FAS compound heterozygous variants c.310T > A (p.C104S) and c.702_704del (p.T235del) were identified. The apoptotic ability of T cells was defective, and FAS expression on the surface of T cells was deficient. The T235del variant decreased FAS expression, and the C104S protein remained in the endoplasmic reticulum (ER) and could not translocate to the cell surface. Both mutations resulted in loss-of-function in terms of FAS-induced apoptosis in HEK293T cells. The DNTs were mainly terminally differentiated T (TEMRA) and CD45RA+HLA-DR+, with high expression of CD85j, PD-1, and CD57. The percentage of Th1, Tfh, and autoreactive B cells were significantly increased in the patient. The abnormal immunophenotyping was partially attenuated by sirolimus treatment. CONCLUSIONS: We identified two variants that significantly affect FAS expression or localization, leading to early disease onset of in the fetus. Abnormalities in the mTOR pathway are associated with a favorable response to sirolimus.

Intrinsic functional defects in B cells of patients with NFKB2 mutations.

Mutations in the human nuclear factor-κB2 gene (NFKB2) are associated with common variable immunodeficiency (CVID) or combined immunodeficiency diseases (CID), characterized by B-cell lymphopenia, hypogammaglobulinemia, and T cell dysfunction. This study investigated whether B cells with NFKB2 mutations exhibit intrinsic impairments in activation, class-switch recombination, and differentiation. We analyzed five patients from four unrelated families with CVID, each carrying a heterozygous NFKB2 mutation: P1 (C.2595_2614del, p.A867Gfs*12), P2 (C.2597G>A, p.S866N), P3 (C.2540dupT, p.R848Efs*38), and P4 and P5 (C.2570_2571insCAGCACA, p.A860Qfs*28). The patients with frameshift mutations (P1, P3, P4, and P5) exhibited truncated proteins detectable in their peripheral blood mononuclear cells, while P2 had a missense mutation. All identified mutations disrupted the processing of p100 into the active p52 form, resulting in NF-κB2 loss-of-function and IκBδ gain-of-function. Clinically, P1, P2, and P3 exhibited B-cell lymphopenia, and all five patients presented with hypogammaglobulinemia. Notably, P2 exhibited a markedly low B-cell count, associated with increased proportions of memory B and IgD-CD27- double negative B cells. In vitro experiments with naïve B cells from P1 and P4 demonstrated decreased survival, impaired activation, and reduced differentiation into CD27+IgD- cells and plasmablasts, while class switch recombination was unaffected. These findings reveal novel B cell-intrinsic functional defects in patients with NFKB2 mutations.

Clinical and Genetic Characteristics of BCG Disease in Chinese Children: a Retrospective Study.

PURPOSE: Summarize the characteristics of a large cohort of BCG disease and compare differences in clinical characteristics and outcomes among different genotypes and between primary immunodeficiency disease (PID) and patients without identified genetic etiology. METHODS: We collected information on patients with BCG disease in our center from January 2015 to December 2020 and divided them into four groups: chronic granulomatous disease (CGD), Mendelian susceptibility to mycobacterial disease (MSMD), severe combined immunodeficiency disease (SCID), and gene negative group. RESULTS: A total of 134 patients were reviewed, and most of them had PID. A total of 111 (82.8%) patients had 18 different types of pathogenic gene mutations, most of whom (91.0%) were classified with CGD, MSMD, and SCID. CYBB was the most common gene mutation (52/111). BCG disease behaves differently in individuals with different PIDs. Significant differences in sex (P < 0.001), age at diagnosis (P = 0.013), frequency of recurrent fever (P = 0.007), and vaccination-homolateral axillary lymph node enlargement (P = 0.039) and infection severity (P = 0.006) were noted among the four groups. The CGD group had the highest rate of males and the oldest age at diagnosis. The MSMD group had the highest probability of disseminated infection (48.3%). The course of anti-tuberculosis treatment and the survival time between patients with PID and without identified genetic etiology were similar. CONCLUSION: Greater than 80% of BCG patients have PID; accordingly, gene sequencing should be performed in patients with BCG disease for early diagnosis. BCG disease behaves differently in patients with different types of PID. Patients without identified genetic etiology had similar outcomes to PID patients, which hints that they may have pathogenic gene mutations that need to be discovered.

Variant Type X91+ Chronic Granulomatous Disease: Clinical and Molecular Characterization in a Chinese Cohort.

PURPOSE: We aimed to report the clinical and immunological characteristics of variant type X91+ chronic granulomatous disease (CGD) in a Chinese cohort. METHODS: The clinical manifestations and immunological phenotypes of patients with X91+ CGD were collected. A dihydrorhodamine (DHR) analysis was performed to evaluate neutrophil function. Gp91phox protein expression was determined using extracellular staining with the monoclonal antibody (mAb) 7D5 and flow cytometry. RESULTS: Patients with X91+ CGD accounted for 8% (7/85) of all patients with CGD. The median age of onset in the seven patients with X91+ CGD was 4 months. Six patients received the BCG vaccine, and 50% (3/6) had probable BCG infections. Mycobacterium tuberculosis infection was prominent. The most common sites of infection were the lung (6/7), lymph nodes (5/7), and soft tissue (3/7). Two patients experienced recurrent oral ulcers. The stimulation index (SI) of the patients with X91+ CGD ranged widely from 1.9 to 67.3. The difference in the SI among the three groups of patients (X91+ CGD, X91- CGD, and X910 CGD) was statistically significant (P = 0.0071). The three groups showed no significant differences in onset age, diagnosis age, or severe infection frequency. CYBB mutations associated with X91+ CGD were commonly located in the second transmembrane or intracellular regions. Three novel X91+ CGD-related mutations (c.1462-2 A > T, c.1243C > T, and c.925G > A) were identified. CONCLUSIONS: Variant type X91+ CGD may result in varied clinical manifestations. Moreover, the laboratory findings might indicate a moderate neutrophil SI. We should deepen our understanding of variant X91+ CGD to prevent missed diagnoses.

Efficacy of tocilizumab therapy in a patient with severe pancytopenia associated with a STAT3 gain-of-function mutation.

BACKGROUND: We aimed to report the clinical characteristics, immunological features, and treatment of one patient with a de novo STAT3 gain-of-function mutation identified by next generation sequencing. We investigated the efficacy of tocilizumab therapy in immune dysregulation diseases caused by STAT3 mutation. RESULTS: The patient was a 16-year-old girl. She presented with recurrent respiratory infections and chronic diarrhea after birth. She had life-threatening autoimmune pancytopenia at 14 years old. After receiving glucocorticoid therapy, she developed diabetes. However, her pancytopenia relapsed when the glucocorticoid was tapered. Next-generation sequencing showed a de novo heterozygous mutation in the STAT3 gene, c.1261G > A (p. G421R), which was previously described as a gain-of-function mutation. After tocilizumab therapy, her pancytopenia fully resolved, and insulin and glucocorticoid therapies were gradually discontinued within 12 months. She had lymphopenia and an inverted CD4/CD8 ratio before therapy. Lymphocyte subpopulation analysis indicated an expansion of effector memory CD4+, effector memory CD8+ and central memory CD4+ T cells. The proportions of memory B cells and naive CD4+ T cells were decreased, and the proportion of naïve B cells was increased. None of the abnormal lymphocytic changes improved significantly. STAT3 GOF mutations were identified by next gene sequencing in those with early-onset multi-organ autoimmunity. Including our patient, 13 patients with STAT3 GOF mutations received targeted treatment. Twelve of them were treated with tocilizumab alone or combination tocilizumab with JAK inhibitor, and ten patients improved. CONCLUSIONS: Gene sequencing should be performed for patients with early-onset refractory or multiorgan immune dysregulation diseases. Targeted drugs can effectively improve the clinical problems associated with STAT3 gain-of-function mutations, while nontargeted immunosuppressive therapy is usually insufficient.

Novel Heterogeneous Mutation of TNFAIP3 in a Chinese Patient with Behçet-Like Phenotype and Persistent EBV Viremia.

PURPOSE: Tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) is a negative regulator of the nuclear factor-κB (NF-κB) pathway. It has recently been recognized that TNFAIP3 deficiency leads to early onset of autoinflammatory and autoimmune syndrome resembling Behçet's disease. Here, we report a novel mutation in TNFAIP3 in a Chinese patient, who had Behçet-like phenotype and persistent Epstein-Barr virus (EBV) viremia. METHODS: The clinical data were collected. Immunological function was detected. Gene mutation was detected by whole-exome sequencing (WES) and confirmed by Sanger sequencing. mRNA and protein levels were detected in the patient under lipopolysaccharide (LPS) stimulation by real-time PCR and Western blot. RESULTS: The patient is a 13-year-old boy, presenting with intermittent fever for 5 months, who also experienced diffuse lymphadenopathy, arthritis, and recurrent multiple gastrointestinal ulcers. EBV DNA was detected in the serum and peripheral blood mononuclear cells of the patient. The immunological phenotype showed increased proportion of double-negative T cells (CD3+CD4-CD8-). A novel missense mutation (c.1428G > A) locating at the zinc fingers 2 (ZF2) domain of TNFAIP3 inherited from his mother was confirmed. Compared with age-matched healthy controls, decrease expression of A20 was observed in the patient. The NF-κB pathway was found to be overactivated, and the synthesis of TNF-α was upregulated in the patient-derived cells. However, cells from the mother showed a milder response to LPS than cells from the patient. CONCLUSIONS: The present research indicated that the TNFAIP3 mutation of c.1428G > A (p.M476I) leads to the reduced suppression of NF-κB activation and accounted for the autoinflammatory phenotype and persistent EBV viremia in the patient.

Report of a Chinese Cohort with Leukocyte Adhesion Deficiency-I and Four Novel Mutations.

PURPOSE: We aimed to report the characteristics of leukocyte adhesion deficiency-I (LAD-I) and four novel mutations in the ITGB2 gene in a Chinese cohort. METHODS: Seven patients with LAD-I were reported in our study. Clinical manifestations and immunological phenotypes were reviewed. The expression of CD18 was detected by flow cytometry. Next-generation sequencing (NGS) and Sanger sequencing were performed to identify gene mutations. RESULTS: The mean onset age of all the patients was 1.3 months. Recurrent bacterial infections of the skin and lungs were the most common symptoms. Most patients (6/7) had delayed cord separation. The number of white blood cells (WBC) was increased significantly, except that two patients had a mild increase in the number of WBC during infection-free periods. The expression of CD18 was very low in all patients. Homozygous or compound heterozygous mutations in the ITGB2 gene were identified in each patient. Four mutations were novel, including c.1794dupC (p.N599Qfs*93), c.1788C>A (p.C596X), c.841-849del9, and c.741+1delG. Two patients had large deletions of the ITGB2 gene. Five patients were cured by hematopoietic stem cell transplantation (HSCT). CONCLUSIONS: This study reported the clinical and molecular characteristics of a Chinese patient cohort. It is helpful in understanding the current status of the disease in China.

Current Status of the Management of Mendelian Susceptibility to Mycobacterial Disease in Mainland China.

PURPOSE: Although many studies have investigated Mendelian susceptibility to mycobacterial disease (MSMD) worldwide, there is no report of the long-term clinical management and prognosis for MSMD in China. METHODS: This is a cohort study from January 2000 to June 2018. Three hundred and twenty-four patients with bacillus Calmette-Guérin (BCG) infection were diagnosed during this period, and those with MSMD diagnosed by genetic and functional experiments were enrolled in the study. The clinical and genetic characteristics and management of these MSMD patients were summarized. RESULTS: Thirty patients diagnosed with MSMD were followed up. The age at the follow-up end point ranged from 5 to 173 months. Among the patients, IL12RB1 mutations were identified in 22, IFNGR1 mutations in 5, STAT1 mutations in 2, and IFNGR2 mutation in 1. The medium age at onset was 3 months. BCG infection involved multiple organs, including regional infection (8/30; 26.7%) or distant or disseminated infection (22/30; 73.3%). Ten percent (30/324) of patients with BCG infection had a confirmed MSMD diagnosis. Protein expression of IL12RB1 or IFNGR1 was decreased in all patients with IL12RB1 or IFNGR1 mutation, respectively, as indicated by flow cytometry. In addition, 77.8% of patients received rhIFN-γ treatment, which can improve the prognosis of patients with IL12RB1 deficiency. Two patients received stem cell transplantation. Twenty-five patients remained alive at the time of publication. CONCLUSION: MSMD is an important cause of BCG infection. Flow cytometric detection of IL12RB1 and IFNGR1 expression is very useful for rapid MSMD diagnosis. rhIFN-γ therapy is effective in patients with MSMD, particularly improving prognosis in those with IL12RB1 deficiency.

A multimorphic mutation in IRF4 causes human autosomal dominant combined immunodeficiency.

Interferon regulatory factor 4 (IRF4) is a transcription factor (TF) and key regulator of immune cell development and function. We report a recurrent heterozygous mutation in IRF4, p.T95R, causing an autosomal dominant combined immunodeficiency (CID) in seven patients from six unrelated families. The patients exhibited profound susceptibility to opportunistic infections, notably Pneumocystis jirovecii, and presented with agammaglobulinemia. Patients' B cells showed impaired maturation, decreased immunoglobulin isotype switching, and defective plasma cell differentiation, whereas their T cells contained reduced TH17 and TFH populations and exhibited decreased cytokine production. A knock-in mouse model of heterozygous T95R showed a severe defect in antibody production both at the steady state and after immunization with different types of antigens, consistent with the CID observed in these patients. The IRF4T95R variant maps to the TF's DNA binding domain, alters its canonical DNA binding specificities, and results in a simultaneous multimorphic combination of loss, gain, and new functions for IRF4. IRF4T95R behaved as a gain-of-function hypermorph by binding to DNA with higher affinity than IRF4WT. Despite this increased affinity for DNA, the transcriptional activity on IRF4 canonical genes was reduced, showcasing a hypomorphic activity of IRF4T95R. Simultaneously, IRF4T95R functions as a neomorph by binding to noncanonical DNA sites to alter the gene expression profile, including the transcription of genes exclusively induced by IRF4T95R but not by IRF4WT. This previously undescribed multimorphic IRF4 pathophysiology disrupts normal lymphocyte biology, causing human disease.

Increased expression of the TLR7/9 signaling pathways in chronic active EBV infection.

We aimed to investigate the immunological mechanisms of the Toll-like receptor (TLR) signaling pathways in different types of Epstein-Barr virus (EBV) infection. We retrospectively summarized the clinical data, routine laboratory tests and the immunological function of the infectious mononucleosis (IM) and chronic active EBV infection (CAEBV) patients. A real-time quantitative PCR array was used to detect the mRNA expression levels of TLR7/TLR9 and myeloid-differentiation factor 88 (MyD88). Flow cytometry was used to detect the protein expression of TLR7/TLR9. The MyD88 and nuclear factor-κB (NF-κB) (p65) protein were detected by western blotting. A cytometric bead array (CBA) assay was used to detect the expression of downstream cytokines. CAEBV patients presented with increased expression of TLR7/TLR9 in monocytes and B lymphocytes. TLR9 expression in the B lymphocytes of IM patients was decreased compared with the CAEBV pateints. Downstream signaling mediators, including MyD88 and NF-κB, were revealed to be increased in EBV-infected patients. Moreover, the expression of MyD88 and NF-κB was higher in CAEBV patients, leading to disrupted balance of downstream cytokines. EBV may activate the immune system via TLR7/TLR9 signaling pathways. Moreover, the overactivated TLR7/TLR9 pathway in CAEBV patients resulted in excessive inflammation, which might be relevant to the poor prognosis.

Chromosomal abnormalities related to fever of unknown origin in a Chinese pediatric cohort and literature review.

BACKGROUND: Fever of unknown origin (FUO) has been difficult to diagnose in pediatric clinical practice. With the gradual change in the disease spectrum, genetic factors have received increasing attention. Limited studies have shown an association between FUO and chromosomal abnormalities. In this study, we investigated the clinical and genetic characteristics of patients with FUO presenting with chromosomal abnormalities in a Chinese pediatric cohort. RESULTS: Chromosomal abnormalities were detected in 5.5% (8/145) of the patients with FUO. Six patients with inflammatory fever presented with pharyngitis/amygdalitis (4/6), oral aphthous ulcer (2/6), digestive symptoms (3/6), developmental delay (4/6) and elevated C-reactive protein levels (6/6) during fever. These patients were often considered to have systemic inflammatory diseases, such as Behcet's disease or systemic juvenile idiopathic arthritis. Trisomy 8, 7q11.23 dup, 3p26.3-p26.1 del/17q12 dup, 22q11.21 del, and 6q23.3-q24.1 del were identified in patients with inflammatory fever. The TNFAIP3 gene was included in the 6q23.3-q24.1 deletion fragment. Two patients with central fever were characterized by facial anomalies, developmental delay, seizures and no response to antipyretic drugs and were identified as carrying the de novo 18q22.3-q23 del. By performing a literature review, an additional 19 patients who had FUO and chromosomal abnormalities were identified. Trisomy 8, 6q23.2-q24.3 del and 18q22.3-q23 del were reported to present as fever, similar to the findings of our study. CONCLUSIONS: We emphasized the important role of detecting chromosomal abnormalities in patients with FUO, especially in patients with systemic inflammatory manifestations or developmental delay. Identifying chromosomal abnormalities may change the diagnosis and management of patients with FUO.

Severe G6PD deficiency leads to recurrent infections and defects in ROS production: Case report and literature review.

Purpose: Severe glucose-6-phosphate dehydrogenase (G6PD) deficiency can lead to reduced nicotinamide adenine dinucleotide phosphate oxidase activity in phagocytes, resulting in immunodeficiency, with a limited number of reported cases. Here, we aimed to report a child with severe G6PD deficiency in China and investigate the mechanism of his recurrent infections. Methods: The clinical manifestations and immunological phenotypes of this patient were retrospectively collected. Gene mutation was detected by whole-exome sequencing and confirmed by Sanger sequencing. Dihydrorhodamine (DHR) analysis was performed to measure the respiratory burst of neutrophils. Messenger ribonucleic acid and protein levels were detected in the patient under lipopolysaccharide stimulation by real-time quantitative reverse transcription polymerase chain reaction and Western blot. A review of the literature was performed. Results: A male child with G6PD deficiency presented with recurrent respiratory infections, Epstein‒Barr virus infection and tonsillitis from 8 months of age. Gene testing revealed that the proband had one hemizygous mutation in the G6PD gene (c.496 C>T, p. R166C), inherited from his mother. This mutation might affect hydrophobic binding, and the G6PD enzyme activity of the patient was 0. The stimulation indexes of the neutrophils in the patient and mother were 22 and 37, respectively. Compared with healthy controls, decreased reactive oxygen species (ROS) production was observed in the patient. Activation of nuclear factor kappa-B (NF-κB) signaling was found to be influenced, and the synthesis of tumor necrosis factor alpha (TNF-α) was downregulated in the patient-derived cells. In neutrophils of his mother, 74.71% of the X chromosome carrying the mutated gene was inactivated. By performing a systematic literature review, an additional 15 patients with severe G6PD deficiency and recurrent infections were identified. Four other G6PD gene mutations have been reported, including c.1157T>A, c.180_182del, c.514C>T, and c.953_976del. Conclusion: Severe G6PD deficiency, not only class I but also class II, can contribute to a chronic granulomatous disease-like phenotype. Decreased reactive oxygen species synthesis led to decreased activation of the NF-κB pathway in G6PD-deficient patients. Children with severe G6PD deficiency should be aware of immunodeficiency disease, and the DHR assay is recommended to evaluate neutrophil function for early identification.

Rapid diagnosis of Talaromyces marneffei infection by metagenomic next-generation sequencing technology in a Chinese cohort of inborn errors of immunity.

Talaromyces marneffei (T. marneffei) is an opportunistic pathogen. Patients with inborn errors of immunity (IEI) have been increasingly diagnosed with T. marneffei in recent years. The disseminated infection of T. marneffei can be life-threatening without timely and effective antifungal therapy. Rapid and accurate pathogenic microbiological diagnosis is particularly critical for these patients. A total of 505 patients with IEI were admitted to our hospital between January 2019 and June 2022, among whom T. marneffei was detected in 6 patients by metagenomic next-generation sequencing (mNGS), and their clinical and immunological characteristics were summarized. We performed a systematic literature review on T. marneffei infections with published immunodeficiency-related gene mutations. All patients in our cohort were confirmed to have genetic mutations in IL12RB1, IFNGR1, STAT1, STAT3, and CD40LG. T. marneffei was detected in both the blood and lymph nodes of P1 with IL12RB1 mutations, and the clinical manifestations were serious and included recurrent fever, weight loss, severe anemia, splenomegaly and lymphadenopathy, all requiring long-term antifungal therapy. These six patients received antifungal treatment, which relieved symptoms and improved imaging findings. Five patients survived, while one patient died of sepsis after hematopoietic stem cell transplantation. The application of mNGS methods for pathogen detection in IEI patients and comparison with traditional diagnosis methods were investigated. Traditional diagnostic methods and mNGS tests were performed simultaneously in 232 patients with IEI. Compared to the traditional methods, the sensitivity and specificity of mNGS in diagnosing T. marneffei infection were 100% and 98.7%, respectively. The reporting time for T. marneffei detection was approximately 26 hours by mNGS, 3-14 days by culture, and 6-11 days by histopathology. T. marneffei infection was first reported in IEI patients with IL12RB1 gene mutation, which expanded the IEI lineage susceptible to T. marneffei. For IEI patients with T. marneffei infection, we highlight the application of mNGS in pathogenic detection. mNGS is recommended as a front-line diagnostic test for rapidly identifying pathogens in complex and severe infections.

Cellular Mechanisms Underlying B Cell Abnormalities in Patients With Gain-of-Function Mutations in the PIK3CD Gene.

Background: Activated phosphoinositide 3 kinase (PI3K) -delta syndrome (APDS) is an inborn error of immunity with variable clinical phenotype of immunodeficiency and immune dysregulation and caused by gain-of-function mutations in PIK3CD. The hallmark of immune phenotype is increased proportions of transitional B cells and plasmablasts (PB), progressive B cell loss, and elevated levels of serum IgM. Objective: To explore unique B cell subsets and the pathomechanisms driving B cell dysregulation beyond the transitional B cell stage in APDS. Methods: Clinical and immunological data was collected from 24 patients with APDS. In five cases, we performed an in-depth analysis of B cell phenotypes and cultured purified naïve B cells to evaluate their survival, activation, Ig gene class switch recombination (CSR), PB differentiation and antibody secretion. We also analyzed PB differentiation capacity of sorted CD27-IgD- double-negative B (DNB) cells. Results: The patients had increased B cell sizes and higher proportions of IgM+ DNB cells than healthy controls (HC). Their naïve B cells exhibited increased death, impaired CSR but relatively normal PB differentiation. Upon stimulation, patient's DNB cells secreted a similar level of IgG but a higher level of IgM than DNB cells from HC. Targeted therapy of PI3K inhibition partially restored B cell phenotypes. Conclusions: The present study suggests additional mechanistic insight into B cell pathology of APDS: (1) decreased peripheral B cell numbers may be due to the increased death of naïve B cells; (2) larger B cell sizes and expanded DNB population suggest enhanced activation and differentiation of naïve B cells into DNB cells; (3) the impaired CSR yet normal PB differentiation can predominantly generate IgM-secreting cells, resulting in elevated IgM levels.

Mutations in GH1 gene and isolated growth hormone deficiency (IGHD): A familial case of IGHD type I and systematic review.

BACKGROUND: Isolated growth hormone deficiency (IGHD) due to mutations in GH1 gene is a rare disease caused by deficient production of endogenous growth hormone (GH). METHODS: We reported the clinical manifestation and genetic diagnosis (whole exome sequencing [WES], nested PCR Sanger sequencing, and rtPCR) of a family with two children with IGHD type I. We conducted a systematic review of cases with IGHD and compared height, and treatment outcomes in subtypes of IGHD. RESULTS: The patients were siblings born of nonconsanguineous parents from the Chinese Han population. The siblings both presented significantly short stature without other apparent abnormalities. The patients carry compound heterozygous mutations in GH1: a deletion and c.456 + 1G > A mutation that led to abnormal splicing. The systematic review identified 365 IGHD cases with GH1 mutations. Among these patients, their body height was most severely impaired in patients with IGHD type Ia, and the height standard deviation score decreased with the age of diagnosis in IGHD type Ia. Patients with IGHD type II had the longest duration of rhGH treatment, while patients with IGHD type Ib had the highest relative height improvement. CONCLUSION: We identified two patients with IGHD type I caused by compound heterozygotic GH1 deletion and splicing mutation. The analysis of previously published IGHD patients suggests differences in linear growth among subtypes of IGHD.

Clinical phenotype of a Chinese patient with RIPK1 deficiency due to novel mutation.

Accumulating evidence indicates that RIPK1 is associated with inflammation and apoptotic. RIPK1 deficiency leads to proinflammatory signaling impaired. However, only few patients with homozygous loss-of-function mutation in RIPK1 gene had been reported until now. Here, we report a Chinese combined immunodeficiency patient. He had recurrent infection, diarrhea after 3 months old. Immune function indicated that T, B and NK cells decreased significantly but immunoglobulins approximately remained normal. Whole-exome sequencing indicated that he had novel compound heterozygous mutations (c.998 C > A from his mother and c.1934 C > T from his father) in RIPK1 gene, which were confirmed by Sanger sequencing. Our study reports novel mutations in RIPK1 gene and new phenotype of patient with RIPK1 deficiency.

The clinical, immunological and genetic features of 12 Chinese patients with STAT3 mutations.

BACKGROUND: Loss-of-function (LOF) mutations in signal transducer and activator of transcription 3 (STAT3) is one of the causes of STAT3 hyperimmunoglobulin E (IgE) syndrome (STAT3-HIES), while gain-of-function (GOF) mutations in STAT3 lead to immune dysregulation diseases. We retrospectively analyzed the age, common clinical symptoms, immunologic and molecular manifestations in 11 patients with LOF STAT3 mutations and 1 patient with a GOF STAT3 mutation. METHODS: Twelve patients were enrolled in our study. Serum immunoglobulin measurements, lymphocyte subset detection and whole-exome sequencing were performed. RESULTS: The median age at diagnosis of STAT3-HIES patients was 4.74 years. Eczema, recurrent respiratory infections, fevers, abscesses and Staphylococcus aureus infections were the classic manifestations. Elevated serum IgE levels are not always observed in conjunction with high eosinophil counts. A moderate viral DNA load was also measured in peripheral blood mononuclear cells. We noticed that c. 1144C>T was the most common mutation site, followed by c.1311C>A. Additionally, c.1311C>A and c. 1826G>C are two novel mutations. Eight patients achieved notable improvement after receiving intravenous immunoglobulin. CONCLUSION: We updated the current knowledge of this topic. We found an earlier median age at diagnosis, a higher survival rate, and a general lack of nonimmunological abnormalities; we also described the treatment details and novel mutations involve in STAT3-HIES and compared STAT3 LOF and GOF mutations.