Hematopoietic Stem- and Progenitor-Cell Gene Therapy for Hurler Syndrome.

BACKGROUND: Allogeneic hematopoietic stem-cell transplantation is the standard of care for Hurler syndrome (mucopolysaccharidosis type I, Hurler variant [MPSIH]). However, this treatment is only partially curative and is associated with complications. METHODS: We are conducting an ongoing study involving eight children with MPSIH. At enrollment, the children lacked a suitable allogeneic donor and had a Developmental Quotient or Intelligence Quotient score above 70 (i.e., none had moderate or severe cognitive impairment). The children received autologous hematopoietic stem and progenitor cells (HSPCs) transduced ex vivo with an α-L-iduronidase (IDUA)-encoding lentiviral vector after myeloablative conditioning. Safety and correction of blood IDUA activity up to supraphysiologic levels were the primary end points. Clearance of lysosomal storage material as well as skeletal and neurophysiological development were assessed as secondary and exploratory end points. The planned duration of the study is 5 years. RESULTS: We now report interim results. The children's mean (±SD) age at the time of HSPC gene therapy was 1.9±0.5 years. At a median follow-up of 2.10 years, the procedure had a safety profile similar to that known for autologous hematopoietic stem-cell transplantation. All the patients showed prompt and sustained engraftment of gene-corrected cells and had supraphysiologic blood IDUA activity within a month, which was maintained up to the latest follow-up. Urinary glycosaminoglycan (GAG) excretion decreased steeply, reaching normal levels at 12 months in four of five patients who could be evaluated. Previously undetectable levels of IDUA activity in the cerebrospinal fluid became detectable after gene therapy and were associated with local clearance of GAGs. Patients showed stable cognitive performance, stable motor skills corresponding to continued motor development, improved or stable findings on magnetic resonance imaging of the brain and spine, reduced joint stiffness, and normal growth in line with World Health Organization growth charts. CONCLUSIONS: The delivery of HSPC gene therapy in patients with MPSIH resulted in extensive metabolic correction in peripheral tissues and the central nervous system. (Funded by Fondazione Telethon and others; ClinicalTrials.gov number, NCT03488394; EudraCT number, 2017-002430-23.).

Lentiviral haematopoietic stem-cell gene therapy for early-onset metachromatic leukodystrophy: long-term results from a non-randomised, open-label, phase 1/2 trial and expanded access.

BACKGROUND: Effective treatment for metachromatic leukodystrophy (MLD) remains a substantial unmet medical need. In this study we investigated the safety and efficacy of atidarsagene autotemcel (arsa-cel) in patients with MLD. METHODS: This study is an integrated analysis of results from a prospective, non-randomised, phase 1/2 clinical study and expanded-access frameworks. 29 paediatric patients with pre-symptomatic or early-symptomatic early-onset MLD with biochemical and molecular confirmation of diagnosis were treated with arsa-cel, a gene therapy containing an autologous haematopoietic stem and progenitor cell (HSPC) population transduced ex vivo with a lentiviral vector encoding human arylsulfatase A (ARSA) cDNA, and compared with an untreated natural history (NHx) cohort of 31 patients with early-onset MLD, matched by age and disease subtype. Patients were treated and followed up at Ospedale San Raffaele, Milan, Italy. The coprimary efficacy endpoints were an improvement of more than 10% in total gross motor function measure score at 2 years after treatment in treated patients compared with controls, and change from baseline of total peripheral blood mononuclear cell (PBMC) ARSA activity at 2 years after treatment compared with values before treatment. This phase 1/2 study is registered with ClinicalTrials.gov, NCT01560182. FINDINGS: At the time of analyses, 26 patients treated with arsa-cel were alive with median follow-up of 3·16 years (range 0·64-7·51). Two patients died due to disease progression and one due to a sudden event deemed unlikely to be related to treatment. After busulfan conditioning, all arsa-cel treated patients showed sustained multilineage engraftment of genetically modified HSPCs. ARSA activity in PBMCs was significantly increased above baseline 2 years after treatment by a mean 18·7-fold (95% CI 8·3-42·2; p<0·0001) in patients with the late-infantile variant and 5·7-fold (2·6-12·4; p<0·0001) in patients with the early-juvenile variant. Mean differences in total scores for gross motor function measure between treated patients and age-matched and disease subtype-matched NHx patients 2 years after treatment were significant for both patients with late-infantile MLD (66% [95% CI 48·9-82·3]) and early-juvenile MLD (42% [12·3-71·8]). Most treated patients progressively acquired motor skills within the predicted range of healthy children or had stabilised motor performance (maintaining the ability to walk). Further, most displayed normal cognitive development and prevention or delay of central and peripheral demyelination and brain atrophy throughout follow-up; treatment benefits were particularly apparent in patients treated before symptom onset. The infusion was well tolerated and there was no evidence of abnormal clonal proliferation or replication-competent lentivirus. All patients had at least one grade 3 or higher adverse event; most were related to conditioning or to background disease. The only adverse event related to arsa-cel was the transient development of anti-ARSA antibodies in four patients, which did not affect clinical outcomes. INTERPRETATION: Treatment with arsa-cel resulted in sustained, clinically relevant benefits in children with early-onset MLD by preserving cognitive function and motor development in most patients, and slowing demyelination and brain atrophy. FUNDING: Orchard Therapeutics, Fondazione Telethon, and GlaxoSmithKline.

Emapalumab treatment in an ADA-SCID patient with refractory hemophagocytic lymphohistiocytosis-related graft failure and disseminated bacillus Calmette-Guérin infection.

Emapalumab, a fully human anti-IFNγ monoclonal antibody, has been approved in the US as second-line treatment of primary hemophagocytic lymphohistiocytosis (HLH) patients and has shown promise in patients with graft failure (GF) requiring a second allogeneic hematopoietic stem cell transplantation (HSCT). The blockade of IFNγ activity may increase the risk of severe infections, including fatal mycobacteriosis. We report a case of secondary HLH-related GF in the context of HLA-haploidentical HSCT successfully treated with emapalumab in the presence of concomitant life-threatening infections, including disseminated tuberculosis (TB). A 4 years old girl with Adenosine Deaminase-Severe Combined Immunodeficiency complicated by disseminated TB came to our attention for ex-vivo hematopoietic stem cell-gene therapy. After engraftment failure of gene corrected cells, she received two HLA-haploidentical T-cell depleted HSCT from the father, both failed due to GF related to concomitant multiple infections and secondary HLH. Emapalumab administration allowed to control HLH, as well as to prevent GF after a third haplo-HSCT from the mother. Remarkably, all infections improved with antimicrobial medications and disseminated TB did not show any reactivation. This seminal case supports emapalumab use for treatment of secondary HLH and prevention of GF in patients undergoing haplo-HSCT even in the presence of multiple infections, including TB.

In Ataxia-Telangiectasia, Oral Betamethasone Administration Ameliorates Lymphocytes Functionality through Modulation of the IL-7/IL-7Rα Axis Paralleling the Neurological Behavior: A Comparative Report of Two Cases.

Ataxia-Telangiectasia (A-T) is characterized by cerebellar neurodegeneration and immunodeficiency. Recent studies suggest that very low glucocorticoids (GCs) doses may help improve A-T neurological phenotype in some patients. Interestingly, in GCs studies an unexpected improvement of lymphocytes proliferation in some A-T patients has been observed. GCs are able to upregulate IL-7 Rα expression and rescue it from the recycling. In this study, we compared several immunological functions, including PBMC proliferative responses, cell activation events and IL-7/IL-7 Rα axis functionality, with the neurological behavior during an in-vivo GCs treatment between the most Responder patient to GC and the Non-Responder at all. During in-vivo GC treatment, we observed an increase of lymphocyte proliferation upon stimulation with PHA or IL-7 only in the Responder. This finding paralleled the increase in the surface expression of IL-7 R and up-regulation of the CD69 T-cell activation marker. Internalization and recycling of IL-7 R occurred properly only in the Responder. Microarray analysis revealed a remarkable difference in the DE-genes levels among Responder and Non-Responder, mostly concerning miRNAs and Multiple Complex families. Our findings suggest that the improvement of lymphocyte functionality, which correlates to the neurological behavior, is mediated through an effect of GCs on the IL-7/IL-7 Rα axis.

Follow-up and outcome of symptomatic partial or absolute IgA deficiency in children.

Selective IgA deficiency is defined as absolute or partial when serum IgA level is < 7 mg/dl or 2 SD below normal for age, respectively. Few data are available on partial selective IgA deficiency, as probably most children with low serum IgA are seldom referred to a specialist clinic in common pediatric practice. The aim of our study was to better define the profile of both symptomatic forms and their clinical outcome in a pediatric immunology setting. Thus, clinical and immunological data from 103 symptomatic patients with selective IgA deficiency (53 absolute and 50 partial), 4-18 years of age, were collected at diagnosis and 80 patients (44 absolute and 36 partial) were monitored for a mean period of 5 years. Also, the prevalence of TNFRSF13B mutations has been assessed in 56 patients. The most common clinical features were infections (86/103; 83%), allergy (39/103; 38%), and autoimmunity (13/103; 13%). No significative differences were observed between absolute and partial selective IgA deficiency patients. However, a significative difference in the rate of IgA normalization between partial and absolute selective IgA deficiency patients (33 vs 9%, p = 0.01) was detected. Furthermore, a lower incidence of infections was associated to a normalization reversal compared to a final absolute or partial defect status (12 vs 53 and 64% respectively, p < 0.01).Conclusions: Regardless of a diagnosis of absolute or partial defect, monitoring of symptomatic patients with selective IgA deficiency is recommended overtime for prompt identification and treatment of associated diseases. Further, diagnostic workup protocols should be revisited in children with IgA deficiency. What is Known: ● Selective IgA Deficiency is the most common primary immunodeficiency and is usually asymptomatic. ● Symptomatic pediatric patients with selective IgA deficiency mostly suffer with respiratory and gastrointestinal infections. What is New: ● Symptomatic children with partial IgA defect may have similar clinical, immunological, and genetic features than symptomatic children with absolute IgA deficiency. ● Symptomatic children with partial IgA deficiency deserve accurate monitoring for associated diseases as per children with absolute IgA deficiency.

Biweekly Hizentra® in Primary Immunodeficiency: a Multicenter, Observational Cohort Study (IBIS).

Immunoglobulin G (IgG) replacement therapy is a standard treatment for patients with primary immunodeficiency diseases (PIDs). Hizentra®, a 20% human subcutaneous IgG (SCIG), is approved for biweekly administration for PIDs. The aim of the multicenter IBIS study was to prospectively investigate the efficacy of biweekly Hizentra® compared with previous IVIG or SCIG treatment regimens in patients with PIDs. The study consisted of a 12-month retrospective period followed by 12-month prospective observational period. The main endpoints included pre-infusion IgG concentrations, proportion of patients with serious bacterial infections (SBIs), other infections, hospitalizations due to PID-related illnesses, and days with antibiotics during the study periods. Of the 36 patients enrolled in the study, 35 patients continued the study (mean age 26.1 ± 14.4 years; 68.6% male). The mean pre-infusion IgG levels for prior immunoglobulin regimens during the retrospective period (7.84 ± 2.09 g/L) and the prospective period (8.55 ± 1.76 g/L) did not show any significant variations (p = 0.4964). The mean annual rate of SBIs/patient was 0.063 ± 0.246 for both prospective and retrospective periods. No hospitalizations related to PIDs were reported during the prospective period versus one in the retrospective period. All patients were either very (76.5%) or quite (23.5%) satisfied with biweekly Hizentra® at the end of the study. In conclusion, the IBIS study provided real-world evidence on the efficacy of biweekly Hizentra® in patients with PIDs, thus verifying the data generated by the pharmacometric modeling and simulation study in a normal clinical setting.

Otolaryngological features in a cohort of patients affected with 22q11.2 deletion syndrome: A monocentric survey.

Otorhinolaryngologic manifestations are common in 22q11.2 deletion syndrome (22q11.2DS), but poorly described. This study aimed to better define the ear-nose-throat (ENT) phenotype of 22q11.2DS patients, in the attempt to best detect subjects requiring subspecialist intervention. We enrolled 25 patients affected with 22q11.2DS. Anatomic and functional ENT findings were investigated using clinical, laboratory, and instrumental data. Immunophenotype and frequency of infections were evaluated. Univariate and multivariate analyses were performed. ENT anomalies were found in 88% of patients, and in 20% congenital palate defects required surgery. Adenoid or palatine tonsil hypertrophy was noted in 80% and 48%. Forty-eight percent of subjects had rhinolalia/phonia, severe in half of these. We also found nasal regurgitation or laryngeal penetration/aspiration in 20% and 16%, respectively. Instrumental exams revealed a mild conductive hearing loss in 32% (bilateral in most cases), tympanometric anomalies in 28%, and swallowing abnormalities in 16%. Statistical univariate analysis showed a direct association between rhinolalia/phonia and episodes of laryngeal aspiration (p = .016) and between tympanometric anomalies and increased adenoid volume (p = .044). No association between episodes of food aspiration and palatal anomalies was found. Moreover, no statistically significant association was observed between the number of airway infections and the ENT findings. This study contributes to better define the ENT phenotype in patients with 22q11.2DS, helpful to prevent potential complications. Furthermore, the identification of a subcategory of patients may allow the early adoption of specific speech therapy programs to improve the clinical outcome of 22q11.2DS patients.

FOXN1 Deficiency: from the Discovery to Novel Therapeutic Approaches.

Since the discovery of FOXN1 deficiency, the human counterpart of the nude mouse, a growing body of evidence investigating the role of FOXN1 in thymus and skin, has been published. FOXN1 has emerged as fundamental for thymus development, function, and homeostasis, representing the master regulator of thymic epithelial and T cell development. In the skin, it also plays a pivotal role in keratinocytes and hair follicle cell differentiation, although the underlying molecular mechanisms still remain to be fully elucidated. The nude severe combined immunodeficiency phenotype is indeed characterized by the clinical hallmarks of athymia with severe T cell immunodeficiency, congenital alopecia, and nail dystrophy. In this review, we summarize recent discoveries in the field and give interesting perspective about new and promising therapeutic approaches for disorders of immune system with athymia.

DiGeorge-like syndrome in a child with a 3p12.3 deletion involving MIR4273 gene born to a mother with gestational diabetes mellitus.

Chromosome 22q11.2 deletion is the most common chromosomal alteration associated with DiGeorge syndrome (DGS), even though this is not the only underlying cause of DGS. In rare patients, mutations in a single gene, TBX1, have been described resulting in a DGS phenotype. Recently, it has been reported that at least part of the TBX1 mutant phenotype is due to excessive bone morphogenetic proteins (BMP) signaling. Evidence suggests that miRNA may modulate the expression of critical T-box transcriptional regulators during midface development and Bmp-signaling. We report on a 7-year-old Caucasian male born to a mother affected with gestational diabetes (GDM) who had a 371Kb-interstitial deletion of 3p12.3 identified by array CGH, involving the ZNF717, MIR1243, and 4273 genes. The child presented with a DiGeorge anomaly (DGA) associated with unilateral renal agenesis and language delay. The immunological evaluation revealed a severe reduction and impairment of T lymphocytes. FISH analysis and TBX1 sequencing were negative. Among the miRNA-4273 predicted target genes, we found BMP3, which is involved in several steps of embryogenesis including kidney and lung organogenesis and in insulin gene expression. Since, DGA is not commonly found in newborns of diabetic mothers, we hypothesize that the pathogenesis of DGA associated with GDM is multifactorial, involving both genetic and/or epigenetic cofactors.

B cells from nuclear factor kB essential modulator deficient patients fail to differentiate to antibody secreting cells in response to TLR9 ligand.

Hypohidrotic ectodermal dysplasia (HED) consists of disorders resulting from molecular alterations of ectodysplasin-A (EDA) pathway. Hypomorphic mutations in NF-kB essential modulator, downstream EDA, result in HED with immunodeficiency (HED-ID), characterized by susceptibility to encapsulated pyogenic bacteria infections. Increased susceptibility to pneumococcal infections and poor response to polysaccharide antigens are associated with defect in T-independent B-cell immunity. We investigated B-cell differentiation and immunoglobulin secretion induced by the TLR9 ligand CpG in two HED-ID and in a HED patient caused by EDA mutations (XLHED). In HED-ID, only few B cells differentiated into plasma cells upon TLR9 stimulation and memory B cells did not produce IgG and IgA, but small amounts of IgM. Unexpectedly, memory B cells from XLHED patient failed to produce normal IgA or IgG amount upon TLR9 stimulation. Our findings expand the knowledge about the pathogenesis of humoral alterations in HED patients and help explain the susceptibility to pneumococcal infections.

Intergenerational and intrafamilial phenotypic variability in 22q11.2 deletion syndrome subjects.

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is a common microdeletion syndrome, which occurs in approximately 1:4000 births. Familial autosomal dominant recurrence of the syndrome is detected in about 8-28% of the cases. Aim of this study is to evaluate the intergenerational and intrafamilial phenotypic variability in a cohort of familial cases carrying a 22q11.2 deletion. METHODS: Thirty-two 22q11.2DS subjects among 26 families were enrolled. RESULTS: Second generation subjects showed a significantly higher number of features than their transmitting parents (212 vs 129, P = 0.0015). Congenital heart defect, calcium-phosphorus metabolism abnormalities, developmental and speech delay were more represented in the second generation (P < 0.05). Ocular disorders were more frequent in the parent group. No significant difference was observed for the other clinical variables. Intrafamilial phenotypic heterogeneity was identified in the pedigrees. In 23/32 families, a higher number of features were found in individuals from the second generation and a more severe phenotype was observed in almost all of them, indicating the worsening of the phenotype over generations. Both genetic and epigenetic mechanisms may be involved in the phenotypic variability. CONCLUSIONS: Second generation subjects showed a more complex phenotype in comparison to those from the first generation. Both ascertainment bias related to patient selection or to the low rate of reproductive fitness of adults with a more severe phenotype, and several not well defined molecular mechanism, could explain intergenerational and intrafamilial phenotypic variability in this syndrome.

Gastrointestinal involvement in patients affected with 22q11.2 deletion syndrome.

OBJECTIVE. Enteropathy is a very common feature in patients with primary immunodeficiencies. In patients with Del22 gastrointestinal (GI) alterations, including feeding disorders and congenital abnormalities have been often reported, mostly in the first year of life. MATERIAL AND METHODS. Aim of this monocentric study is to better define the GI involvement in a cohort of 26 patients affected with Del22 syndrome. Anamnestic information was retrospectively collected for each patient. Weight and height parameters at the time of the screening were recorded. Plasma levels of hemoglobin, iron, ferritin, albumin, total protein, calcium, phosphorus, transaminase levels, antigliadin (AGA) IgA and IgG, and antitissue transglutaminase (anti-TGase) titers were measured. RESULTS. A GI involvement was identified in the 58% of patients. The prominent problems were abdominal pain, vomiting, gastroesophageal reflux and chronic constipation. Weight deficiency, short stature and failure to thrive were reported in 54, 42, and 30% of the patients, respectively. The evidence of sideropenic anemia, in keeping with hypoproteinemia, impaired acid steatocrit or cellobiose/mannitol test suggested an abnormal intestinal permeability. In this cohort, a high prevalence of AGA IgA and IgG positivity was observed. Celiac disease (CD) was suspected in three patients, and in one of them confirmed by histology. In this patient, a long-lasting gluten-free diet failed to restore the intestinal architecture. CONCLUSIONS. In conclusion, GI involvement is a very common feature in Del22 patients. A better characterization of GI involvement would be very useful to improve the management of these patients.

Early skeletal outcomes after hematopoietic stem and progenitor cell gene therapy for Hurler syndrome.

Mucopolysaccharidosis type I Hurler (MPSIH) is characterized by severe and progressive skeletal dysplasia that is not fully addressed by allogeneic hematopoietic stem cell transplantation (HSCT). Autologous hematopoietic stem progenitor cell-gene therapy (HSPC-GT) provides superior metabolic correction in patients with MPSIH compared with HSCT; however, its ability to affect skeletal manifestations is unknown. Eight patients with MPSIH (mean age at treatment: 1.9 years) received lentiviral-based HSPC-GT in a phase 1/2 clinical trial (NCT03488394). Clinical (growth, measures of kyphosis and genu velgum), functional (motor function, joint range of motion), and radiological [acetabular index (AI), migration percentage (MP) in hip x-rays and MRIs and spine MRI score] parameters of skeletal dysplasia were evaluated at baseline and multiple time points up to 4 years after treatment. Specific skeletal measures were retrospectively compared with an external cohort of HSCT-treated patients. At a median follow-up of 3.78 years after HSPC-GT, all patients treated with HSPC-GT exhibited longitudinal growth within WHO reference ranges and a median height gain greater than that observed in patients treated with HSCT after 3-year follow-up. Patients receiving HSPC-GT experienced complete and earlier normalization of joint mobility compared with patients treated with HSCT. Mean AI and MP showed progressive decreases after HSPC-GT, suggesting a reduction in acetabular dysplasia. Typical spine alterations measured through a spine MRI score stabilized after HSPC-GT. Clinical, functional, and radiological measures suggested an early beneficial effect of HSPC-GT on MPSIH-typical skeletal features. Longer follow-up is needed to draw definitive conclusions on HSPC-GT's impact on MPSIH skeletal dysplasia.

Long-term and real-world safety and efficacy of retroviral gene therapy for adenosine deaminase deficiency.

Adenosine deaminase (ADA) deficiency leads to severe combined immunodeficiency (SCID). Previous clinical trials showed that autologous CD34+ cell gene therapy (GT) following busulfan reduced-intensity conditioning is a promising therapeutic approach for ADA-SCID, but long-term data are warranted. Here we report an analysis on long-term safety and efficacy data of 43 patients with ADA-SCID who received retroviral ex vivo bone marrow-derived hematopoietic stem cell GT. Twenty-two individuals (median follow-up 15.4 years) were treated in the context of clinical development or named patient program. Nineteen patients were treated post-marketing authorization (median follow-up 3.2 years), and two additional patients received mobilized peripheral blood CD34+ cell GT. At data cutoff, all 43 patients were alive, with a median follow-up of 5.0 years (interquartile range 2.4-15.4) and 2 years intervention-free survival (no need for long-term enzyme replacement therapy or allogeneic hematopoietic stem cell transplantation) of 88% (95% confidence interval 78.7-98.4%). Most adverse events/reactions were related to disease background, busulfan conditioning or immune reconstitution; the safety profile of the real world experience was in line with premarketing cohort. One patient from the named patient program developed a T cell leukemia related to treatment 4.7 years after GT and is currently in remission. Long-term persistence of multilineage gene-corrected cells, metabolic detoxification, immune reconstitution and decreased infection rates were observed. Estimated mixed-effects models showed that higher dose of CD34+ cells infused and younger age at GT affected positively the plateau of CD3+ transduced cells, lymphocytes and CD4+ CD45RA+ naive T cells, whereas the cell dose positively influenced the final plateau of CD15+ transduced cells. These long-term data suggest that the risk-benefit of GT in ADA remains favorable and warrant for continuing long-term safety monitoring. Clinical trial registration: NCT00598481 , NCT03478670 .

Hemophagocytic inflammatory syndrome in ADA-SCID: report of two cases and literature review.

Hemophagocytic inflammatory syndrome (HIS) is a rare form of secondary hemophagocytic lymphohistiocytosis caused by an impaired equilibrium between natural killer and cytotoxic T-cell activity, evolving in hypercytokinemia and multiorgan failure. In the context of inborn errors of immunity, HIS occurrence has been reported in severe combined immunodeficiency (SCID) patients, including two cases of adenosine deaminase deficient-SCID (ADA-SCID). Here we describe two additional pediatric cases of ADA-SCID patients who developed HIS. In the first case, HIS was triggered by infectious complications while the patient was on enzyme replacement therapy; the patient was treated with high-dose corticosteroids and intravenous immunoglobulins with HIS remission. However, the patient required HLA-identical sibling donor hematopoietic stem cell transplantation (HSCT) for a definitive cure of ADA-SCID, without HIS relapse up to 13 years after HSCT. The second patient presented HIS 2 years after hematopoietic stem cell gene therapy (GT), secondarily to Varicella-Zoster vaccination and despite CD4+ and CD8+ lymphocytes' reconstitution in line with other ADA SCID patients treated with GT. The child responded to trilinear immunosuppressive therapy (corticosteroids, Cyclosporine A, Anakinra). We observed the persistence of gene-corrected cells up to 5 years post-GT, without HIS relapse. These new cases of children with HIS, together with those reported in the literature, support the hypothesis that a major dysregulation in the immune system can occur in ADA-SCID patients. Our cases show that early identification of the disease is imperative and that a variable degree of immunosuppression could be an effective treatment while allogeneic HSCT is required only in cases of refractoriness. A deeper knowledge of immunologic patterns contributing to HIS pathogenesis in ADA-SCID patients is desirable, to identify new targeted treatments and ensure patients' long-term recovery.

Outcome of BCG Vaccination in ADA-SCID Patients: A 12-Patient Series.

Vaccination with Bacillus Calmette-Guérin (BCG) can be harmful to patients with combined primary immunodeficiencies. We report the outcome of BCG vaccination in a series of twelve patients affected by adenosine deaminase deficiency (ADA-SCID). BCG vaccination resulted in a very high incidence of complications due to uncontrolled replication of the mycobacterium. All patients who developed BCG-related disease were treated successfully and remained free from recurrence of disease. We recommend the prompt initiation of enzyme replacement therapy and secondary prophylaxis to reduce the risk of BCG-related complications in ADA-SCID patients.

Wiskott-Aldrich syndrome: Oral findings and microbiota in children and review of the literature.

OBJECTIVE: Wiskott-Aldrich syndrome (WAS) is a rare X-linked primary immunodeficiency, characterized by micro-thrombocytopenia, recurrent infections, and eczema. This study aims to describe common oral manifestations and evaluate oral microbioma of WAS patients. MATERIAL AND METHODS: In this cohort study, 11 male WAS patients and 16 male healthy controls were evaluated in our Center between 2010 and 2018. Data about clinical history, oral examination, Gingival Index (GI) and Plaque Index (PI) were collected from both groups. Periodontal microbiological flora was evaluated on samples of the gingival sulcus. RESULTS: WAS subjects presented with premature loss of deciduous and permanent teeth, inclusions, eruption disturbance, and significantly worse GI and PI. They also showed a trend toward a higher total bacterial load. Fusobacterium nucleatum, reported to contribute to periodontitis onset, was the most prevalent bacteria, together with Porphyromonas gingivalis and Tannerella forsythia. CONCLUSIONS: Our data suggest that WAS patients are at greater risk of alterations in the oral cavity. The statistically higher incidence of periodontitis and the trend to higher prevalence of potentially pathological bacterial species in our small cohort, that should be confirmed in future in a larger population, underline the importance of dentistry monitoring as part of the multidisciplinary management of WAS patients.

Peripheral blood stem and progenitor cell collection in pediatric candidates for ex vivo gene therapy: a 10-year series.

Hematopoietic stem and progenitor cell (HSPC)-based gene therapy (GT) requires the collection of a large number of cells. While bone marrow (BM) is the most common source of HSPCs in pediatric donors, the collection of autologous peripheral blood stem cells (PBSCs) is an attractive alternative for GT. We present safety and efficacy data of a 10-year cohort of 45 pediatric patients who underwent PBSC collection for backup and/or purification of CD34+ cells for ex vivo gene transfer. Median age was 3.7 years and median weight 15.8 kg. After mobilization with lenograstim/plerixafor (n = 41) or lenograstim alone (n = 4) and 1-3 cycles of leukapheresis, median collection was 37 × 106 CD34+ cells/kg. The procedures were well tolerated. Patients who collected ≥7 and ≥13 × 106 CD34+ cells/kg in the first cycle had pre-apheresis circulating counts of at ≥42 and ≥86 CD34+ cells/µL, respectively. Weight-adjusted CD34+ cell yield was positively correlated with peripheral CD34+ cell counts and influenced by female gender, disease, and drug dosage. All patients received a GT product above the minimum target, ranging from 4 to 30.9 × 106 CD34+ cells/kg. Pediatric PBSC collection compares well to BM harvest in terms of CD34+ cell yields for the purpose of GT, with a favorable safety profile.

Clinical, Immunological, and Functional Characterization of Six Patients with Very High IgM Levels.

Very high IgM levels represent the hallmark of hyper IgM (HIGM) syndromes, a group of primary immunodeficiencies (PIDs) characterized by susceptibility to infections and malignancies. Other PIDs not fulfilling the diagnostic criteria for HIGM syndromes can also be characterized by high IgM levels and susceptibility to malignancies. The aim of this study is to characterize clinical phenotype, immune impairment, and pathogenic mechanism in six patients with very high IgM levels in whom classical HIGM syndromes were ruled out. The immunological analysis included extended B-cell immunophenotyping, evaluation of class switch recombination and somatic hypermutation, and next generation sequencing (NGS). Recurrent or severe infections and chronic lung changes at the diagnosis were reported in five out of six and two out of six patients, respectively. Five out of six patients showed signs of lymphoproliferation and four patients developed malignancies. Four patients showed impaired B-cell homeostasis. Class switch recombination was functional in vivo in all patients. NGS revealed, in one case, a pathogenic mutation in PIK3R1. In a second case, the ITPKB gene, implicated in B- and T-cell development, survival, and activity was identified as a potential candidate gene. Independent of the genetic basis, very high IgM levels represent a risk factor for the development of recurrent infections leading to chronic lung changes, lymphoproliferation, and high risk of malignancies.