Mutations in EXTL3 Cause Neuro-immuno-skeletal Dysplasia Syndrome.

EXTL3 regulates the biosynthesis of heparan sulfate (HS), important for both skeletal development and hematopoiesis, through the formation of HS proteoglycans (HSPGs). By whole-exome sequencing, we identified homozygous missense mutations c.1382C>T, c.1537C>T, c.1970A>G, and c.2008T>G in EXTL3 in nine affected individuals from five unrelated families. Notably, we found the identical homozygous missense mutation c.1382C>T (p.Pro461Leu) in four affected individuals from two unrelated families. Affected individuals presented with variable skeletal abnormalities and neurodevelopmental defects. Severe combined immunodeficiency (SCID) with a complete absence of T cells was observed in three families. EXTL3 was most abundant in hematopoietic stem cells and early progenitor T cells, which is in line with a SCID phenotype at the level of early T cell development in the thymus. To provide further support for the hypothesis that mutations in EXTL3 cause a neuro-immuno-skeletal dysplasia syndrome, and to gain insight into the pathogenesis of the disorder, we analyzed the localization of EXTL3 in fibroblasts derived from affected individuals and determined glycosaminoglycan concentrations in these cells as well as in urine and blood. We observed abnormal glycosaminoglycan concentrations and increased concentrations of the non-sulfated chondroitin disaccharide D0a0 and the disaccharide D0a4 in serum and urine of all analyzed affected individuals. In summary, we show that biallelic mutations in EXTL3 disturb glycosaminoglycan synthesis and thus lead to a recognizable syndrome characterized by variable expression of skeletal, neurological, and immunological abnormalities.

Health-Related Quality of Life and Emotional Health in X-Linked Carriers of Chronic Granulomatous Disease in the United Kingdom.

X-linked chronic granulomatous disease (XL-CGD), a rare primary immunodeficiency due to a defect in the gp91phox NADPH oxidase subunit, results in recurrent, severe infection, inflammation, and autoimmunity. Patients have an absent, or significantly reduced, neutrophil oxidative burst. Due to lyonization, XL-CGD carriers have a dual population of functional and non-functional phagocytes and experience a range of symptoms including increased risk of autoimmunity, fatigue, and infection. Patients with CGD have poorer quality of life (QoL) than normal controls. We evaluated QoL and psychological health in UK XL-CGD carriers. Recruited participants completed the Medical Outcomes Study Short Form 36 version 2 (SF-36 V2), providing an overall score for mental and physical health. Psychological health was assessed using the Hospital Anxiety and Depression Scale (HADS) questionnaire. Seventy-five XL-CGD carriers were recruited from 62 families, median age 43 years (range 3-77). Fifty-six were mothers, 6 grandmothers, and 13 siblings. Sixty-two completed the SF36v2 and had reduced QoL scores compared with adult CGD patients and a UK age-matched female control cohort, indicating a reduced QoL. Sixty-one completed a HADS questionnaire. Over 40% experienced moderate or greater levels of anxiety with only one third being classified as normal. Higher anxiety scores significantly correlated with higher depression scores, lower self-esteem, presence of joint or bowel symptoms, and higher levels of fatigue (p < 0.05). This is the first study to evaluate QoL of XL-CGD carriers, and demonstrates high rates of anxiety and significantly reduced QoL scores. XL-CGD carriers should be considered as potential patients and pro-actively assessed and managed.

Correction to: Raised Serum IL-8 Levels Are Associated with Excessive Fatigue in Female Carriers of X-Linked Chronic Granulomatous Disease in the UK.

The original version of the article, "Raised Serum IL-8 Levels Are Associated with Excessive Fatigue in Female Carriers of X-Linked Chronic Granulomatous Disease in the UK" incorrectly listed the name of the fourth author as Fai W. Ng. The correct spelling of the author's name is WF Ng.

Immunodeficiency and severe susceptibility to bacterial infection associated with a loss-of-function homozygous mutation of MKL1.

Megakaryoblastic leukemia 1 (MKL1), also known as MAL or myocardin-related transcription factor A (MRTF-A), is a coactivator of serum response factor, which regulates transcription of actin and actin cytoskeleton-related genes. MKL1 is known to be important for megakaryocyte differentiation and function in mice, but its role in immune cells is unexplored. Here we report a patient with a homozygous nonsense mutation in the MKL1 gene resulting in immunodeficiency characterized predominantly by susceptibility to severe bacterial infection. We show that loss of MKL1 protein expression causes a dramatic loss of filamentous actin (F-actin) content in lymphoid and myeloid lineage immune cells and widespread cytoskeletal dysfunction. MKL1-deficient neutrophils displayed reduced phagocytosis and almost complete abrogation of migration in vitro. Similarly, primary dendritic cells were unable to spread normally or to form podosomes. Silencing of MKL1 in myeloid cell lines revealed that F-actin assembly was abrogated through reduction of globular actin (G-actin) levels and disturbed expression of multiple actin-regulating genes. Impaired migration of these cells was associated with failure of uropod retraction likely due to altered contractility and adhesion, evidenced by reduced expression of the myosin light chain 9 (MYL9) component of myosin II complex and overexpression of CD11b integrin. Together, our results show that MKL1 is a nonredundant regulator of cytoskeleton-associated functions in immune cells and fibroblasts and that its depletion underlies a novel human primary immunodeficiency.

Post-thaw viability of cryopreserved peripheral blood stem cells (PBSC) does not guarantee functional activity: important implications for quality assurance of stem cell transplant programmes.

Standard quality assurance (QA) of cryopreserved peripheral blood stem cells (PBSC) uses post-thaw viable CD34(+) cell counts. In 2013, concerns arose at Great Ormond Street Hospital (GOSH) about 8 patients with delayed engraftment following myeloablative chemotherapy with cryopreserved cell rescue, despite adequate post-thaw viable cell counts in all cases. Root cause analysis was undertaken; investigations suggested the freeze process itself was a contributing factor to suboptimal engraftment. Experiments were undertaken in which a single PBSC product was divided into three and cryopreserved in parallel using a control-rate freezer (CRF) or passive freezing method (-80°C freezer) at GOSH, or the same passive freezing at another laboratory. Viable CD34(+) counts were equivalent and adequate in each. Granulocyte-monocyte colony-forming unit assays demonstrated colonies from the products cryopreserved using passive freezing (both laboratories), but no colonies from products cryopreserved using the CRF. The CRF was shown to be operating within manufacturer's specifications with freeze-profile within acceptable limits. This experience has important implications for quality assurance for all transplant programmes, particularly those using cryopreserved products. The failure of post-thaw viable CD34(+) counts, the most widely used routine QA test available, to ensure PBSC function is of great concern and should prompt reassessment of protocols and QA procedures.

Signal transducer and activator of transcription 2 deficiency is a novel disorder of mitochondrial fission.

Defects of mitochondrial dynamics are emerging causes of neurological disease. In two children presenting with severe neurological deterioration following viral infection we identified a novel homozygous STAT2 mutation, c.1836 C>A (p.Cys612Ter), using whole exome sequencing. In muscle and fibroblasts from these patients, and a third unrelated STAT2-deficient patient, we observed extremely elongated mitochondria. Western blot analysis revealed absence of the STAT2 protein and that the mitochondrial fission protein DRP1 (encoded by DNM1L) is inactive, as shown by its phosphorylation state. All three patients harboured decreased levels of DRP1 phosphorylated at serine residue 616 (P-DRP1(S616)), a post-translational modification known to activate DRP1, and increased levels of DRP1 phosphorylated at serine 637 (P-DRP1(S637)), associated with the inactive state of the DRP1 GTPase. Knockdown of STAT2 in SHSY5Y cells recapitulated the fission defect, with elongated mitochondria and decreased P-DRP1(S616) levels. Furthermore the mitochondrial fission defect in patient fibroblasts was rescued following lentiviral transduction with wild-type STAT2 in all three patients, with normalization of mitochondrial length and increased P-DRP1(S616) levels. Taken together, these findings implicate STAT2 as a novel regulator of DRP1 phosphorylation at serine 616, and thus of mitochondrial fission, and suggest that there are interactions between immunity and mitochondria. This is the first study to link the innate immune system to mitochondrial dynamics and morphology. We hypothesize that variability in JAK-STAT signalling may contribute to the phenotypic heterogeneity of mitochondrial disease, and may explain why some patients with underlying mitochondrial disease decompensate after seemingly trivial viral infections. Modulating JAK-STAT activity may represent a novel therapeutic avenue for mitochondrial diseases, which remain largely untreatable. This may also be relevant for more common neurodegenerative diseases, including Alzheimer's, Huntington's and Parkinson's diseases, in which abnormalities of mitochondrial morphology have been implicated in disease pathogenesis.

Host natural killer immunity is a key indicator of permissiveness for donor cell engraftment in patients with severe combined immunodeficiency.

BACKGROUND: Severe combined immunodeficiency (SCID) can be cured by using allogeneic hematopoietic stem cell transplantation, and the absence of host immunity often obviates the need for preconditioning. Depending on the underlying genetic defect and when blocks in differentiation occur during lymphocyte ontogeny, infants with SCID have absent or greatly reduced numbers of functional T cells. Natural killer (NK) cell populations are usually absent in the SCID-X1 and Janus kinase 3 forms of SCID and greatly reduced in adenosine deaminase deficiency SCID but often present in other forms of the disorder. OBJECTIVE: To determine if SCID phenotypes indicate host permissiveness to donor cell engraftment. METHODS: A retrospective data analysis considered whether host NK cells influenced donor T-cell engraftment, immune reconstitution, and long-term outcomes in children who had undergone nonconditioned allogeneic stem cell transplantation between 1990 and 2011 in the United Kingdom. Detailed analysis of T- and B-cell immune reconstitution and donor chimerism was compared between the NK(+) (n = 24) and NK(-) (n = 53) forms of SCID. RESULTS: Overall, 77 children underwent transplantation, with survival of 90% in matched sibling donor/matched family donor transplants compared with 60% when alternative donors were used. Infants with NK(-)SCID were more likely to survive than NK(+) recipients (87% vs 62%, P < .01) and had high-level donor T-cell chimerism with superior long-term recovery of CD4 T-cell immunity. Notably, 33% of children with NK(+)SCID required additional transplantation procedures compared with only 8% of children with NK(-)SCID (P < .005). CONCLUSIONS: NK(-)SCID disorders are highly permissive for donor T-cell engraftment without preconditioning, whereas the presence of NK cells is a strong indicator that preparative conditioning is required for engraftment of T-cell precursors capable of supporting robust T-cell reconstitution.

Clinical outcome in children with chronic granulomatous disease managed conservatively or with hematopoietic stem cell transplantation.

BACKGROUND: Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by serious infections and inflammation. It can be managed conservatively with prophylactic antimicrobial agents or curatively with hematopoietic stem cell transplantation (HSCT). In the United Kingdom and Ireland there are cohorts of children managed both conservatively and curatively. OBJECTIVES: This study aimed to compare clinical outcomes (mortality and morbidity) in children managed conservatively and curatively. METHODS: Children were identified from specialist centers and advertising through special interest groups. Clinical data were collected from medical records regarding infections, inflammatory complications and growth, other admissions, and curative treatment. Comparisons were made for patients not undergoing HSCT and patients after HSCT. RESULTS: Seventy-three living children were identified, 59 (80%) of whom were recruited. Five deceased children were also identified. Clinical information was available for 62 children (4 deceased). Thirty (48%) children had undergone HSCT. Children who did not undergo transplantation had 0.71 episodes of infection/admission/surgery per CGD life year (95% CI, 0.69-0.75 events per year). Post-HSCT children had 0.15 episodes of infection/admission/surgery per transplant year (95% CI, 0.09-0.21 events per year). The mean z score for height and body mass index (BMI) for age was significantly better in post-HSCT children. Survival in the non-HSCT group was 90% at age 15 years. Survival in the post-HSCT group was 90%. CONCLUSIONS: Children with CGD not undergoing transplantation have more serious infections, episodes of surgery, and admissions compared with post-HSCT children. Children undergoing transplantation have better height for age. Survival is good at the end of the pediatric age range and also after HSCT.

The many faces of Artemis-deficient combined immunodeficiency - Two patients with DCLRE1C mutations and a systematic literature review of genotype-phenotype correlation.

Defective V(D)J recombination and DNA double-strand break (DSB) repair severely impair the development of T-lymphocytes and B-lymphocytes. Most patients manifest a severe combined immunodeficiency during infancy. We report 2 siblings with combined immunodeficiency (CID) and immunodysregulation caused by compound heterozygous Artemis mutations, including an exon 1-3 deletion generating a null allele, and a missense change (p.T71P). Skin fibroblasts demonstrated normal DSB repair by gamma-H2AX analysis, supporting the predicted hypomorphic nature of the p.T71P allele. In addition to these two patients, 12 patients with Artemis-deficient CID were previously reported. All had significant morbidities including recurrent infections, autoimmunity, EBV-associated lymphoma, and carcinoma despite having hypomorphic mutants with residual Artemis expression, V(D)J recombination or DSB repair capacity. Nine patients underwent stem cell transplant and six survived, while four patients who did not receive transplant died. The progressive nature of immunodeficiency and genomic instability accounts for poor survival, and early HSCT should be considered.

Health related quality of life and emotional health in children with chronic granulomatous disease: a comparison of those managed conservatively with those that have undergone haematopoietic stem cell transplant.

PURPOSE: Chronic Granulomatous Disease (CGD) is a rare primary immunodeficiency that predisposes to life-threatening infections and inflammation. Haematopoietic stem cell transplant (HSCT) can cure CGD. Chronic illness reduces quality of life. Children with haematological malignancies report improved quality of life post-HSCT. There are no data for children with CGD. This study evaluated quality of life and emotional well-being in CGD children treated conventionally or transplanted. METHODS: Parents and children completed the Pediatric Quality of Life Inventory v4.0 (PedsQL) and Strengths and Difficulties Questionnaires (SDQ). Mean scores were compared with published UK norms. Comparisons were made for those that had or had not undergone HSCT. RESULTS: Forty-seven parents completed PedsQL (children aged 3-15). Twenty-one were post-HSCT. Forty-two completed SDQ (children aged 3-15). Nineteen post-HSCT. Median age for non-HSCT group 9 years. Median age for post-HSCT group 10 years. The HSCT group were median 3 years post-HSCT (range 1-9 years). HSCT survival was 90 %-two died without completing questionnaires Parent and self-reported quality of life for non-transplanted children was significantly lower than healthy children. Parents reported increased emotional difficulties compared to published norms. PedsQL and SDQ scores for transplanted children were not significantly different from healthy norms. CONCLUSIONS: This study demonstrates the quality of life is reduced in CGD. Transplanted patients have quality of life comparable to levels reported in healthy children. This data will help inform families and clinicians when deciding about treatment and may have relevance for other immunodeficiencies treated with transplant.

Cognitive ability in children with chronic granulomatous disease: a comparison of those managed conservatively with those who have undergone hematopoietic stem cell transplant.

Chronic granulomatous disease (CGD) is a primary immunodeficiency managed conservatively or with hematopoietic stem cell transplant. Studies have shown people with CGD and those transplanted for primary immunodeficiencies have lower than average cognitive ability. In this study, IQ in children with CGD and those transplanted for it was within the normal range.

Human inherited complete STAT2 deficiency underlies inflammatory viral diseases.

STAT2 is a transcription factor activated by type I and III IFNs. We report 23 patients with loss-of-function variants causing autosomal recessive (AR) complete STAT2 deficiency. Both cells transfected with mutant STAT2 alleles and the patients' cells displayed impaired expression of IFN-stimulated genes and impaired control of in vitro viral infections. Clinical manifestations from early childhood onward included severe adverse reaction to live attenuated viral vaccines (LAV) and severe viral infections, particularly critical influenza pneumonia, critical COVID-19 pneumonia, and herpes simplex virus type 1 (HSV-1) encephalitis. The patients displayed various types of hyperinflammation, often triggered by viral infection or after LAV administration, which probably attested to unresolved viral infection in the absence of STAT2-dependent types I and III IFN immunity. Transcriptomic analysis revealed that circulating monocytes, neutrophils, and CD8+ memory T cells contributed to this inflammation. Several patients died from viral infection or heart failure during a febrile illness with no identified etiology. Notably, the highest mortality occurred during early childhood. These findings show that AR complete STAT2 deficiency underlay severe viral diseases and substantially impacts survival.

Omission of in vivo T-cell depletion promotes rapid expansion of naïve CD4+ cord blood lymphocytes and restores adaptive immunity within 2 months after unrelated cord blood transplant.

Umbilical cord blood transplant (UCBT) is associated with impaired early immune reconstitution. This might be explained by a lower T-cell dose infused, the naivety of cord blood T-cells and the use of in vivo T-cell depletion. We studied the pattern of early immune reconstitution and the clinical outcome of children undergoing unrelated UCBT when in vivo T-cell depletion was omitted. Thirty children affected by malignancies (46%) or immunodeficiencies (54%) underwent an unrelated UCBT. Prospective assessment of immune reconstitution and clinical outcome was performed. We observed an unprecedented CD4(+) T-cell reconstitution, with a median cell count at 30 and 60 d post UCBT of 0.3 × 10(9) /l and 0.56 × 10(9) /l, respectively. Early T-cell expansion was thymic-independent, with a rapid shift from naïve to central memory phenotype and early regulatory T-cell recovery. Viral infections were frequent (63%) but resolved rapidly in most cases and virus-specific T-lymphocytes were detected within 2 months post-UCBT. Acute graft-versus-host disease (GvHD) was frequent (grade II = 34%, grade III-IV = 16%) but steroid responsive, and the incidence of chronic GvHD was low (14%). The omission of in vivo T-cell depletion promotes a unique thymic-independent CD4(+) T-cell reconstitution after unrelated UCBT in children. We postulate that this relates to the specific immunological and ontological qualities of fetal-derived lymphocytes.

Role of immunoglobulin supplementation for secondary immunodeficiency associated with chylothorax after pediatric cardiothoracic surgery.

OBJECTIVE: To evaluate whether intravenous immunoglobulin was linked to a reduction in sepsis in patients with prolonged chylothoraces postpediatric cardiothoracic surgery. DESIGN: Retrospective observational cohort study. SETTING: Tertiary pediatric cardiac surgical center. PATIENTS: Children with chylothoraces postcardiothoracic surgery from 1998 to 2006 divided into two groups: with and without intravenous immunoglobulin supplementation. INTERVENTION: Intravenous immunoglobulin supplementation. MEASUREMENTS AND MAIN RESULTS: Thirty-seven with chylothoraces (median duration 14 days; interquartile range, 10-32 and median maximum chyle drainage 1.9 mL/kg/hr; interquartile range, 1-3) were included, and 16 (43%) received intravenous immunoglobulin. The degree of lymphopenia was worse with longer duration of chylothorax (p = .005). There was a trend toward immunoglobulin depletion-IgG (p = .07) and IgM (p = .07) with higher volume chyle loss. Twenty-two of 37 (59%) developed bloodstream infection and 24 of 37 (65%) developed sepsis related to other organ systems. The rate of bloodstream infection and of sepsis in other organ systems was high at 25 (95% confidence interval 17-39) and 23 (95% confidence interval 15-34) episodes per 1,000 intensive care unit days, respectively. Intravenous immunoglobulin was not related to the bloodstream infection rate: adjusted hazard ratio 0.88 (95% confidence interval 0.20-3.94; p = .87) or rate of sepsis in other organ systems: hazard ratio 2.31 (95% confidence interval 0.21-24.29; p = .49) or the proportion surviving to hospital discharge (p = .37). CONCLUSION: Patients with prolonged, large-volume chyle loss had greater secondary immunodeficiency. Although the sample size was small and therefore able to detect only a large treatment effect from intravenous immunoglobulin, infectious outcomes were equal between the two groups.

STAT3-Deficient hyperimmunoglobulin E syndrome: report of a case with orofacial granulomatosis-like disease.

Hyperimmunoglobulin E syndrome (HIES) is a rare heterogeneous primary immunodeficiency disorder characterized by infections of the lung and skin, elevated serum immunoglobulin E, and involvement of soft and bony tissues. Autosomal dominant HIES and related disorders are caused by defects in the Janus activated kinase-signal transducer and activator of transcription signaling pathway, leading to reduced numbers of T helper cell type 17 and impaired production of interleukin (IL)-17 A, IL-17 F, and IL-22. In addition, neutrophils have chemotactic defects, resulting in impaired responses at skin and lung sites. We report here a case of orofacial granulomatosis-like disease in a teenage boy ultimately found to have autosomal dominant HIES caused by a heterozygous mutation in the STAT3 gene.

Immunological abnormalities in CHARGE syndrome.

Immune deficiency can be part of CHARGE syndrome but often receives only limited attention. We present two patients with CHARGE syndrome confirmed CHD7 mutations who had severe T-cell deficiency, and review 15 CHARGE patients from the literature with immunological problems. Most of them had severe T-cell deficiency, although the spectrum also included mild T-cell deficiency and isolated humoral immune deficiency. We conclude that immunodeficiency can form an important symptom in CHARGE syndrome although the frequency and exact nature are still insufficiently known. We propose to evaluate immune functions in all CHARGE syndrome patients, to estimate the frequency and nature of the accompanying immunodeficiency, and to obtain better data regarding prognosis and management.