X-linked Chronic Granulomatous Disease Research Articles

50 Utilizing an Ethical Lens to Assess a Series of Patients With X-Linked CGD Who Did Not Undergo Hematopoietic Stem Cell Transplant

50 Utilizing an Ethical Lens to Assess a Series of Patients With X-Linked CGD Who Did Not Undergo Hematopoietic Stem Cell Transplant

In adult X-CGD patients, regulatory T cells are expanded while activated T cells display a NOX2-independent ROS increase

The X-linked chronic granulomatous disease (X-CGD), a rare genetic disease characterised by recurrent infections, is caused by mutations of NOX2. Significant proportions of X-CGD patients display signs of immune dysregulation. Regulatory T cells (Tregs) are CD4+T lymphocytes that expand in active inflammation and prevent autoimmune disorders. Here we asked whether X-CGD is associated to Treg dysfunctions in adult patients. To this aim, the frequency of Tregs was analysed through intracellular flow cytometry in a cohort of adult X-CGD patients, carriers and controls. We found that Tregs were significantly expanded and activated in blood of adult X-CGD patients, and this was associated with activation of conventional CD4+T cells (Tconvs). T cell activation was characterised by accumulation of intracellular ROS, not derived from NOX2 but likely produced by cellular metabolism. The higher TNF production by Tconvs in X-CGD patients might contribute to the expansion of Tregs through the TNFR2 receptor. In summary, our data indicate that Tregs expand in adult X-CGD in response to immune activation, and that the increase of NOX2-independent ROS content is a feature of activated T cells.

Gene regulation in inborn errors of immunity: Implications for gene therapy design and efficacy.

Inborn errors of immunity (IEI) present a unique paradigm in the realm of gene therapy, emphasizing the need for precision in therapeutic design. As gene therapy transitions from broad-spectrum gene addition to careful modification of specific genes, the enduring safety and effectiveness of these therapies in clinical settings have become crucial. This review discusses the significance of IEIs as foundational models for pioneering and refining precision medicine. We explore the capabilities of gene addition and gene correction platforms in modifying the DNA sequence of primary cells tailored for IEIs. The review uses four specific IEIs to highlight key issues in gene therapy strategies: X-linked agammaglobulinemia (XLA), X-linked chronic granulomatous disease (X-CGD), X-linked hyper IgM syndrome (XHIGM), and immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX). We detail the regulatory intricacies and therapeutic innovations for each disorder, incorporating insights from relevant clinical trials. For most IEIs, regulated expression is a vital aspect of the underlying biology, and we discuss the importance of endogenous regulation in developing gene therapy strategies.

Macrophage Activation Syndrome Secondary to Histoplasmosis in an Adult Female Carrier of X-linked Chronic Granulomatous Disease with Extreme Lyonization.

not applicable to a Letter to the Editor.

X-linked chronic granulomatous disease secondary to skewed X-chromosome inactivation in female patients.

Chronic granulomatous disease (CGD) is a heterogeneous primary immunodeficiency. X-linked (XL) CGD caused by gene defects of CYBB is the most prevalent type of CGD. We aim to understand the clinical and molecule features of XL-CGD secondary to skewed X-chromosome inactivation (XCI) in female. We retrospectively reviewed the medical records of a female patient diagnosed with XL-CGD. Flow cytometry was used to detect the respiratory burst function. After restriction enzyme digestion of DNA, XCI was calculated by detecting fluorescent PCR products with capillary electrophoresis. The previously published female XL-CGD cases secondary to skewed XCI was summarized. Clinical data were available for 15 female subjects. The median age of diagnosis was 16 years. Consistent with XL-CGD in males, infection was the most frequent manifestation in the female patients. Catalase-positive pathogens including Serratia marcescens and Staphylococcus aureus infections were the most common pathogens. Autoimmune/autoinflammation manifestations were observed in five patients. Dihydrorhodamine (DHR) assay showed that median %DHR+ values were 6.5% and the values varying with age were observed in 2 patients. All patients had a skewing XCI and there was no consistency between the daughter and carrier mother. Anti-infective treatment was effective in majority and there was no mortality reported in XL-CGD female patients to date. XL-CGD should not be neglected in female patients manifested as CGD phenotype and it is necessary to make periodic clinical evaluation of CGD female carriers as the neutrophil oxidative function may decline with aging and increase the risk for infection.

Carrier State of Chronic Granulomatous Disease Presented at Middle Age: A Case Report

Introduction: Chronic granulomatous disease (CGD) is the most common inherited defect of phagocytes. Although most female carriers of X-linked CGD have been considered to be unaffected, they may have similar problems to those of CGD patients. This study suggests that the CGD carrier state might be more complex than it was previously appreciated. Case Presentation: A sixty-year-old woman visited our hospital in June 2021 due to pneumonia and pleural effusion. Chest computed tomography scan revealed left lower lobe pneumonia and mediastinal lymphadenopathies. In July 2021, her symptoms (high-grade fever, chills, and hemoptysis) were initially attributed to a hydatid cyst. Therefore, she underwent a lobectomy, resulting in purulent drainage on the excision site on the skin, refractory to local and systemic treatments. The refractory and recurrent nature of the lesions led to the immunological evaluation, which was completely normal with a 100% nitroblue tetrazolium (NBT) and a dihydrorhodamine (DHR) of 278 (normal > 100). Further DHR123 flow cytometry investigations with multiple stimulants revealed a carrier state of CGD, which was relevant to her history of chronic complications. Conclusions: Adult patients with unusual manifestations suggestive of neutrophil function defects in adulthood should be evaluated for the CGD carrier state. In these cases, NBT alone may miss the diagnosis of CGD. In such cases, DHR testing with multiple stimulants may establish a robust diagnosis.

Myelodysplasia after clonal hematopoiesis with APOBEC3-mediated CYBB inactivation in retroviral gene therapy for X-CGD

Stem cell gene therapy using the MFGS-gp91phox retroviral vector was performed on a 27-year-old patient with X-linked chronic granulomatous disease (X-CGD) in 2014. The patient's refractory infections were resolved, whereas the oxidase-positive neutrophils disappeared within 6months. Thirty-two months after gene therapy, the patient developed myelodysplastic syndrome (MDS), and vector integration into the MECOM locus was identified in blast cells. The vector integration into MECOM was detectable in most myeloid cells at 12months after gene therapy. However, the patient exhibited normal hematopoiesis until the onset of MDS, suggesting that MECOM transactivation contributed to clonal hematopoiesis, and the blast transformation likely arose after the acquisition of additional genetic lesions. In whole-genome sequencing, the biallelic loss of the WT1 tumor suppressor gene, which occurred immediately before tumorigenesis, was identified as a potential candidate genetic alteration. The provirus CYBB cDNA in the blasts contained 108 G-to-A mutations exclusively in the coding strand, suggesting the occurrence of APOBEC3-mediated hypermutations during the transduction of CD34-positive cells. A hypermutation-mediated loss of oxidase activity may have facilitated the survival and proliferation of the clone with MECOM transactivation. Our data provide valuable insights into the complex mechanisms underlying the development of leukemia in X-CGD gene therapy.

Detailed characterisation of invasive aspergillosis in a murine model of X-linked chronic granulomatous disease shows new insights in infections caused by Aspergillus fumigatus versus Aspergillus nidulans.

Invasive aspergillosis (IA) is the most prevalent infectious complication in patients with chronic granulomatous disease (CGD). Yet, understanding of fungal pathogenesis in the CGD host remains limited, particularly with regards to A. nidulans infection. We have used a murine model of X-linked CGD to investigate how the pathogenesis of IA varies between A. fumigatus and A. nidulans, comparing infection in both X-linked CGD (gp91-/-) mice and their parent C57BL/6 (WT) mice. A 14-colour flow cytometry panel was used to assess the cell dynamics over the course of infection, with parallel assessment of pulmonary cytokine production and lung histology. We observed a lack of association between pulmonary pathology and infection outcome in gp91-/- mice, with no significant mortality in A. nidulans infected mice. An overwhelming and persistent neutrophil recruitment and IL-1 release in gp91-/- mice following both A. fumigatus and A. nidulans infection was observed, with divergent macrophage, dendritic cell and eosinophil responses and distinct cytokine profiles between the two infections. We have provided an in-depth characterisation of the immune response to pulmonary aspergillosis in an X-linked CGD murine model. This provides the first description of distinct pulmonary inflammatory environments in A. fumigatus and A. nidulans infection in X-linked CGD and identifies several new avenues for further research.

Allogeneic HSCT for Symptomatic Female X-linked Chronic Granulomatous Disease Carriers

X-linked chronic granulomatous disease (XL-CGD) is an inherited disorder of superoxide production, causing failure to generate the oxidative burst in phagocytes. It is characterized by invasive bacterial and fungal infections, inflammation, and chronic autoimmune disease. While XL-CGD carriers were previously assumed to be healthy, a range of clinical manifestations with significant morbidity have recently been described in a subgroup of carriers with impaired neutrophil oxidative burst due to skewed lyonization. Allogeneic hematopoietic stem cell transplantation (HSCT) is the standard curative treatment for CGD but has rarely been reported in individual symptomatic carriers to date. We undertook a retrospective international survey of outcome of HSCT for symptomatic XL-CGD carriers. Seven symptomatic female XL-CGD carriers aged 1–56 years underwent HSCT in four centers, indicated for severe and recurrent infection, colitis, and autoimmunity. Two patients died from transplant-related complications, following donor engraftment and restoration of oxidative burst. All surviving patients demonstrated resolution of their neutrophil oxidative burst defect with concordant reduction in infection and inflammatory symptoms and freedom from further immunosuppressive therapy. In conclusion, allogeneic HSCT may cure the phagocyte defect in symptomatic XL-CGD carriers and improve their recurrent and disabling infective and inflammatory symptoms but risks transplant-related complications.

Detection of CYBA Gene Expression by Reverse Transcription PCR as a Diagnostic Tool for Autosomal Recessive Chronic Granulomatous Disease in a Sample of Egyptian Children

Abstract Chronic granulomatous disease (CGD) is an inherited primary immunodeficiency disease caused by functional impairment of the nicotinamide dinucleotide phosphate (NADPH) oxidase complex in neutrophilic granulocytes and monocytes, characterized by recurrent and severe infections, dysregulated inflammation, and autoimmunity. Approximately two-thirds of patients with CGD have defects in Cytochrome Bβ (CYBB), the X-linked gene encoding glycoprotein 91 phagocytic oxidase (gp91phox). Rarer autosomal recessive (AR) forms of CGD are caused by autosomal recessive mutations in CYBA genes encoding protein 22 phagocytic oxidase (p22phox). However, the incidence of autosomal recessive CGD can be higher than X-linked CGD in countries with high rates of consanguineous marriage. In the present study we aimed to diagnose the commonest AR-type of CGD by detection of CYBA gene expression using real time RT-PCR as a cheaper diagnostic method for CGD subtypes categorization among immunodeficient children. This case-control study was conducted on 15 children provisionally diagnosed as CGD patients with DHR stimulation index using phorbol myristate acetate (PMA) < 30% (Group I). The study also included 12 mothers and 8 fathers of the studied patients to detect the genetic mutations in carriers, if any (Group IIa and IIb respectively), and 14 apparently healthy children as a control group (Group III). We found that cases with a fold change of CYBA gene expression less than 0.6 were considered under-expressed. At this cut-off value, from our molecularly studied subjects 1 case and 2 mothers showed under-expression of CYBA gene. In conclusion, we could establish the diagnosis of AR-form of CGD, derives from defects in the CYBA gene, which encodes p22phox of the NADPH oxidase using real time RT-PCR, without the need to use complex and expensive methodologies such as northern blot, slot blot, or genomic DNA sequencing.

Molecular Challenges in the Diagnosis of X-Linked Chronic Granulomatous Disease: CNVs, Intronic Variants, Skewed X-Chromosome Inactivation, and Gonosomal Mosaicism.

Chronic granulomatous disease (CGD) is a prototypical inborn error of immunity affecting phagocytes, in which these cells are unable to produce reactive oxygen species. CGD is caused by defects in genes encoding subunits of the NADPH oxidase enzyme complex (CYBA, CYBB, CYBC1, NCF1, NCF2, NCF4); inflammatory responses are dysregulated, and patients are highly susceptible to recurrent severe bacterial and fungal infections. X-linked CGD (XL-CGD), caused by mutations in the CYBB gene, is the most common and severe form of CGD. In this study, we describe the analytical processes undertaken in 3 families affected with XL-CGD to illustrate several molecular challenges in the genetic diagnosis of this condition: in family 1, a girl with a heterozygous deletion of CYBB exon 13 and skewed X-chromosome inactivation (XCI); in family 2, a boy with a hemizygous deletion of CYBB exon 7, defining its consequences at the mRNA level; and in family 3, 2 boys with the same novel intronic variant in CYBB (c.1151 + 6T > A). The variant affected the splicing process, although a small fraction of wild-type mRNA was produced. Their mother was a heterozygous carrier, while their maternal grandmother was a carrier in form of gonosomal mosaicism. In summary, using a variety of techniques, including an NGS-based targeted gene panel and deep amplicon sequencing, copy number variation calling strategies, microarray-based comparative genomic hybridization, and cDNA analysis to define splicing defects and skewed XCI, we show how to face and solve some uncommon genetic mechanisms in the diagnosis of XL-CGD.

Novel mutations in CYBB Gene Cause X-linked chronic Granulomatous Disease in Pakistani patients

BackgroundChronic Granulomatous Disease (CGD) is a primary immunodeficiency that causes susceptibility to recurrent fungal and bacterial infections. The CYBB gene encodes gp91phox component of the Phagocytic Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and specifically, X-linked CGD is caused by mutations in the CYBB gene, located on the X chromosome. The aim of the study was to characterize functional and genetic mutations in X-linked CGD.MethodsFunctional analysis was conducted on the whole blood of seventeen male individuals who were suspected to have X-linked chronic granulomatous disease (CGD). Flow cytometry was employed to assess the capacity of NADPH oxidase, measuring both H2O2 production and gp91phox protein expression in neutrophils. Additionally, DNA Sanger sequencing was performed for genetic analysis. The pathogenicity of novel mutations was assessed by pathogenicity prediction tools.ResultAmong the seventeen patients evaluated, five patients (P1, P2, P3, P4, and P5) displayed impaired H2O2 production by their neutrophils upon stimulation with Phorbol myristate acetate (PMA), accompanied by abnormal gp91phox expression. DNA sequencing of the CYBB gene identified specific mutations in each patient. In P1 and P2 (previously reported cases), a hemizygous missense mutation, c.925G > A/p.E309K was identified. In P3 and P4 (novel cases), hemizygous nonsense mutations, c.216T > A/p.C72X were found. Lastly, in P5 (also a novel case), a hemizygous missense mutation, c.732T > G/p.C244W was detected. These mutations reside in exons 9,3 and 7 of the CYBB gene, respectively.ConclusionsThe current study contributes to the understanding of the clinical and genetic spectrum associated with X-linked chronic granulomatous disease (CGD). It highlights the significance of early diagnosis in CGD and emphasizes the importance of lifelong prophylaxis to prevent severe infections.

X-Linked Chronic Granulomatous Disease in a Female Carrier: A Management Challenge

Abstract Chronic granulomatous disease (CGD) is characterized by recurrent bacterial and fungal infections due to reduced nicotinamide adenine dinucleotide phosphate oxidase resulting in impaired production of reactive oxidant species, and aberrant inflammation. X-linked CGD (XL-CGD) is associated with a mutation in the CYBB gene. XL-CGD affects more males, although some females are affected affected due to skewed X-inactivation. Though management guidelines for CGD patients exist, they remain lacking for clinically affected XL-CGD female carriers. A 3 year old female with history of hematochezia, oral ulcers, and recurrent skin infections who presented with fevers and skin pustules. Pustule cultures were positive for B. cepacian, and colonoscopy was non-acute. Immunology had concern for XL-CGD with recent atypical infections and dihydrorhodamine (DHR) flow cytometry was abnormal, 17.7% (normal greater than 95%). DHR 2 months later showed 13% activation. Genetic testing showed a CYBB, c.45+2dup (intronic), heterozygous, VUS, gene mutation affecting the splice site, associated with XL-CGD, and a NOD2, c.3019dup, heterozygous, with a 2–4 fold increased risk for Crohn’s disease. She was started on bacterial prophylaxis only. She is awaiting gp91phox expression for gene sequencing. XL-CGD carriers can be at higher risk for infections, and risk is inversely correlated with %DHR neutrophil counts, but only clinically apparent with %DHR less than 20%, and more as levels are less than 10%. Though our patient was started on Bactrim prophylaxis with her %DHR less than 20%, there remains the question of when and if she should be started on anti-fungal prophylaxis. There remain no clear guidelines on the management of XL-CGD carriers.

Use of Interferon Gamma in Female Carriers of X-linked Chronic Granulomatous Disease

IntroductionChronic granulomatous disease (CGD) is characterized by increased frequency and severity of certain infections, autoimmune disease, and hyperinflammation. Heterozygous female carriers of X-linked CGD may experience similar symptoms. Guidance for management of female carriers is limited. We describe the use of interferon gamma (IFNγ) in X-linked CGD carriers. MethodsA multi-center retrospective chart review identified 4 carriers of X-linked CGD who received prophylaxis with IFNγ. Results of dihydrorhodamine (DHR) assay, infections and autoinflammatory features were documented and adverse events (AE) related to IFNγ were recorded. ResultsFour females (mean age 40 [range 0.5–71] years) received IFNγ (75–100 µg 3 times per week via subcutaneous injection) for a mean duration of 43 (range 16–63) months. Infections prior to the start of IFNγ included sepsis/bacteremia, pneumonia, skin and soft tissue infection, osteomyelitis, and gastroenteritis with CGD-associated pathogens including Serratia marscescens, Burkholderia cepacia, Nocardia spp, and methicillin-resistant Staphylococcus aureus (MRSA). Inflammatory complications (some in more than one subject) included dermatologic (pyoderma gangrenosum [n = 1], unspecified dermatitis [n = 2]), rheumatologic (arthritis [n = 1], Raynaud's syndrome [n = 1]), and gastrointestinal (inflammatory diarrhea [n = 1], Barrett's esophagus [n = 1]). Each carrier exhibited two populations of neutrophil oxidative burst. The populations expressing DHR were as follows: 0.08, 1, 3, and 10.8 +DHR%. Antibacterial prophylaxis was administered in all 4 subjects, and antifungal prophylaxis in 3 subjects. Pre-medications were not administered, and AE associated with IFNγ were mild or moderate in 3 of 4 subjects (one subject had no AE) and did not result in any treatment discontinuations. One patient discontinued prophylaxis with IFNγ after correction of CGD following hematopoietic stem cell transplant. The average length of follow-up since starting IFNγ was 38 months. While on IFNγ therapy, one patient developed atypical mycobacterial and cytomegalovirus pneumonia and MRSA chronic osteomyelitis thought related to poor compliance, while another developed Serratia olecranon abscess/. None developed autoimmune/inflammatory disease while on therapy. ConclusionsThis is the first report to our knowledge of IFNγ use for prophylaxis in carriers of X-linked CGD. IFNγ was well tolerated, and should be considered for prophylaxis in female carriers with very low neutrophil oxidative burst or frequent or severe CGD-associated infections.

Lupus nephritis with clinical and laboratory features of humoral immune deficiency in a 29-year-old female with a novel NCF1 variant consistent with autosomal recessive chronic granulomatous disease

Chronic Granulomatous Disease (CGD) is a rare, inherited disorder of the innate immune system characterized by defects in the phagocyte NADPH oxidase complex. This results in poor phagocyte function causing frequent infections (bacterial and fungal) and chronic inflammation. Here we discuss a rare presentation of lupus nephritis and antibody deficiency in an adult female patient with a novel homozygous nonsense mutation in the NCF-1 gene causing autosomal recessive CGD.Our patient is a 29-year-old female with history of ITP, biopsy-confirmed lupus nephritis, systemic lupus erythematosus (SLE), idiopathic avascular necrosis of the hip, and previous diagnosis of common variable immune deficiency (CVID) treated with Immunoglobulin replacement therapy (IVIG). She presented to our clinic to establish care in the setting of persistent skin abscesses/cellulitis, poor wound healing, necrotic lymphadenitis, and recurrent urinary tract infections and pneumonia despite years of IVIG therapy. She had near-normal total IgG, absent IgA and IgE, and protective vaccine antibody titers (pneumococcus, diphtheria, and tetanus) prior to the start of IVIG. Immunophenotyping demonstrated quantitatively normal number of total B cells, absent CD27+ memory B cells, and normal T cell subsets. She had reassuring lymphocyte proliferation with mitogen stimulation and normal TLR function. Dihydrorhodamine (DHR) flow cytometric assay demonstrated abnormally low neutrophil oxidative burst activity. Gene sequencing revealed homozygous nonsense mutation in the NCF-1 gene (c.75-76del; pY26Hfs*26) and a pathogenic heterozygous variant in FANCM (c.3732-3735dup; p. Leu1246Asnfs*8). She was started on daily prophylactic trimethoprim-sulfamethoxazole and itraconazole. She has marked decrease in infections/hospitalizations and her lupus nephritis is well controlled with hydroxy-chloroquine. She is being referred to the NIH for HSCT evaluation. The majority of CGD cases in the United States are due to X-linked CGD (70%) and AR variants in NCF1 (20%). While rare, discoid lupus erythematosus and SLE have been documented with X-linked forms of CGD. Similarly, there are few case reports of antibody deficiency in patients with CGD. This is the first documented case of AR CGD with SLE/lupus nephritis and humoral immune defects. Additionally, we report a disease-causing, novel variant in the NCF1 gene. This case report adds to the existing literature on CGD and associated diseases.

Abnormal Dihydrorhodamine Result in a Patient with Diabetes Mellitus, Recurrent Candida Liver Abscesses: Diagnostic Possibilities

A 17-year-old female with type I diabetes mellitus (DM) and a history of recurrent candidal vaginal infections and liver abscesses was assessed fora potential neutrophil oxidative burst defect by DHR flow cytometry. The DHR result was abnormal with significantly decreased MFI (MFI = 9; ref. cutoff: >/ = 60) after stimulation with PMA though all of her neutrophils (99%; ref. cutoff >/ = 95%) showed respiratory burst. This DHR pattern has been previously observed in patients with complete myeloperoxidase deficiency (cMPO), p40phox deficiency and hypomorphic X-linked chronic granulomatous disease (CGD). Genetic evaluation of the genes commonly associated with CGD (CYBB, CYBA, NCF1, NCF2 and NCF4) was negative. It must be noted that many genetic laboratories either do not sequence the NCF1 gene or have limited sequencing to the most commonly observed pathogenic variant in exon 2. Most targeted genetic panels currently do not include MPO (myeloperoxidase) or CYBC1 (Eros). The clinical phenotype of Candida infection in the context of diabetes has been previously reported in 5% of cMPO deficiency. The patient underwent a partial hepatectomy and was initiated on an 8-month course of fluconazole. Three months later, there was a recurrence of hepatic abscesses (Figure 1), requiring treatment with a 12-week course of IV micafungin. Complete MPO deficiency can cause a false-positive result on the DHR assay but the pattern is different from that observed in typical XL- and autosomal recessive CGD. There are two ways of confirming cMPO deficiency, besides genetic testing: 1) staining for MPO in neutrophils in a peripheral smear, or 2) repeating the DHR assay and gating on eosinophils as eosinophil peroxidase can overcome the lack of MPO deficiency and demonstrate a normal oxidative burst. These studies are currently under investigation. In summary, cMPO deficiency should be included in the differential diagnosis of patients with diabetes and invasive Candida infections. Communication with the clinical laboratory is essential to identify the DHR pattern and obtain additional confirmatory testing. From a clinical perspective, cMPO-deficient patients do not require prophylactic antibiotics but they have a high rate of recurrence of fungal infections and require aggressive management with antifungal therapies. [Display omitted]

Father and son are carriers of two different types of human inborn errors of immunity: a case report

IntroductionChronic granulomatous disease (CGD) is an inborn error of immunity (IEI) characterized by recurrent bacterial and fungal infections of skin, airways, liver, brain and bones with the estimated prevalence of 1 in 250,000 live births. CGD can inherited either in an X-linked (allelic variants in the CYBB gene) or autosomal recessive mode (allelic variants in the CYBA, NCF1, NCF2, NCF4, and CYBC1 genes). Wiskott-Aldrich syndrome is an X-linked disorder with an estimated incidence of 1 in 100 000 live male births caused by variants in the WAS gene, characterized by microthrombocytopenia, eczema, recurrent infections, increased risk for autoimmune disease and malignancy. Materials and MethodsIn this case report, we present our experience about two cases of blood relatives diagnosed with different types of human inborn errors of immunity. Genetic analysis of CYBB gene in 2007 was performed by Sanger sequencing and of WAS gene in 2022 by next generation amplicon sequencing. All subjects consented to the study. ResultsThe first case was a 15-year-old male (1992 y.o.b., proband) who was diagnosed as X-linked CGD patient in 2007 due to his clinical history and hemizygote allelic variant in the CYBB gene (NM_000397.4: c.484–1G>T, COSV101059810). The second case was a 2-month-old boy (biological son of proband) who was hospitalized in 2022 due to microthrombocytopenia, low platelet volume, cytomegalovirus infection, mild anemia. Genetic analysis revealed in the DNA sample of the second case the hemizygote allelic variant in the WAS gene (NM_000377.3: c.777 +3_777+6del GAGT). Genetic testing didn’t reveal such variant in the DNA sample of the proband's wife, that's why this variant was classified as “de novo”. ConclusionInborn errors of immunity (IEI) present clinically as increased susceptibility to infections, autoimmunity, autoinflammatory diseases, allergy, bone marrow failure, and/or malignancy. There are now a total of 485 IEI, which are segregating to 10 groups of disorders into overlapping phenotypes. Despite the fact that IEI are rare diseases, we have shown that even in one family two different types of disorders can occur. In our case the second IEI was occur due to spontaneously alterations during the process of DNA replication during cell division.

Co-Occurring X-Linked Agammaglobulinemia and X-Linked Chronic Granulomatous Disease: Two Isolated Pathogenic Variants in One Patient

We present a unique and unusual case of a male patient diagnosed with two coexisting and typically unassociated X-linked conditions: he was initially diagnosed with X-linked agammaglobulinemia (XLA) followed by a diagnosis of X-linked chronic granulomatous disease (XCGD) and an as of yet unpublished hypomorphic gp91phox variant in the CYBB gene. The latter was tested after the finding of granulomatous gingivitis. Hematopoietic stem cell transplant (HSCT) was performed due to severe colitis and nodular regenerative hyperplasia (NRH) of the liver. Following transplant, complete donor engraftment was observed with the restoration of a normal oxidative burst and full restoration of normal levels of circulating, mature CD19+ B cells. This case is singular in that it does not involve a contiguous gene syndrome in which deleted genes are in close proximity to either BTK and CYBB, which has been previously reported. To our knowledge, this is the first reported case of XLA and XCGD co-existing in a single patient and of having both inborn errors of immunity successfully treated by HSCT.

CRISPR-gene-engineered CYBB knock-out PLB-985 cells, a useful model to study functional impact of X-linked chronic granulomatous disease mutations: application to the G412E X91+-CGD mutation.

Chronic granulomatous disease (CGD) is a rare primary immune disorder caused by mutations in one of the five subunits of the NADPH oxidase complex expressed in phagocytes. Two-thirds of CGD cases are caused by mutations in CYBB that encodes NOX2 or gp91phox. Some rare X91+-CGD point mutations lead to a loss of function but with a normal expression of the mutated NOX2 protein. It is therefore necessary to ensure that this mutation is indeed responsible for the loss of activity in order to make a safe diagnosis for genetic counselling. We previously used the X-CGD PLB-985 cell model of M.C. Dinauer obtained by homologous recombination in the original PLB-985 human myeloid cell line, in order to study the functional impact of such mutations. Although the PLB-985 cell line was originally described by K.A. Tucker et al. in1987 as a distinct cell line isolated from a patient with acute nonlymphocytic leukemia, it is actually identified as a subclone of the HL-60 cells. In order to use a cellular model that meets the quality standard for the functional study of X91+-CGD mutations in CGD diagnosis, we developed our own model using the CRISPR-Cas9 technology in a certified PLB-985 cell line from DSMZ-German Collection of Microorganisms and Cell Cultures. Thanks to this new X-CGD model, we demonstrated that the G412E mutation in NOX2 found in a X91+-CGD patient prohibits access of the electron donor NADPH to its binding site explaining the absence of superoxide production in his neutrophils.

Clinical features and outcomes of patients with chronic granulomatous disease in Taiwan.

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disease characterized by defective neutrophil killing of microbial pathogens and recurrent infections. We aimed to investigate the clinical, genetic features, treatment, and outcomes in patients with CGD. Pediatric patients diagnosed with CGD from a medical center in Taiwan were enrolled from January 1999 to Oct 2021. Nine pediatric patients with CGD were enrolled: six X-linked (XL) CGD with CYBB gene mutations, three autosomal recessive (AR) CGD with two NCF1 and one CYBA gene mutations.The median age of onset and age of diagnosis was 0.92 and 2.64 years, respectively. Patients with XL-CGD had a younger age of onset (4.6 months vs. 1.83 years, P=0.06) and age of diagnosis (1.71 vs. 8.86 years, P=0.024) than AR-CGD patients. The most common sites of infections were skin and soft tissue abscesses. The most common pathogens were Staphylococcus, Serratia, and Salmonella spp. Prophylactic antibiotics, anti-fungal agents, and interferon-gamma (IFN-γ) were given in 9 (100%), 7 (77.8%), and 8(88.9%) patients, respectively. The mean duration of IFN-γ usage was 5.15 years. One male patient with XL-CGD was successfully treated with hematopoietic stem cell transplantation at 2.2 years. The mortality rate was 11.1%, and the estimated overall survival at 20 years was 66.7%. Staphylococcus aureus, Serratia marcescens, and Salmonella infections are important in Taiwanese CGD patients. Patients with XL-CGD have early disease onset. IFN-γ prophylaxis and prophylactic anti-microbial agents might have an effect on alleviating the infection episodes in CGD patients.