[Analysis of efficacy and prognosis of allogeneic hematopoietic stem cell transplantation for the treatment of combined immunodeficiency].

Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation for the treatment of combined immunodeficiency (CID) and explore prognostic risk factors. Methods: In this retrospective cohort study, clinical characteristics, laboratory tests and prognosis of 73 CID children who underwent allogeneic hematopoietic stem cell transplantation from February 2014 to April 2022 in the Children's Hospital of Fudan University were analyzed. Based on the subtypes of diseases, all patients were divided into severe combined immunodeficiency disease (SCID) group and other CID group. Based on the types of donors, all patients were divided into matched sibling donor group, matched unrelated donor group, unrelated cord blood group, and haploidentical donor group. Kaplan-Meier method and Log-Rank test were used to analyze the survival data. Cox regression was used to analyze prognostic factors. Results: Among the 73 patients, there were 61 (84%) males and 12 (16%) females. Fifty-five (75%) patients were SCID, and 18 (25%) patients were other CID. Donor source included 2 (3%) matched sibling donors (MSD), 3 (4%) matched unrelated donors (MUD), 64 (88%) unrelated cord blood (UCB), and 4 (5%) haploidentical donors. The age at transplant was 10.7 (5.9, 27.5) months, and the follow-up time was 36.2 (2.5, 62.9) months. The 3-year overall survival rate of 73 patients with CID was (67±6) %. No significant difference was found in the 3-year overall survival rates between patients with SCID (55 cases) and other CID (18 cases) ((64±7) % vs. (78±10) %, χ2=1.31, P=0.252). And no significant difference was found in the 3-year overall survival rates among patients who received MSD or MUD (5 cases), UCB (64 cases), and haploidentical donor (4 cases) transplant (100% vs. (66±6)% vs. (50±25) %, χ2=2.30, P=0.317). Cox regression analysis showed that the medical history of sepsis (HR=2.55, 95%CI 1.05-6.20, P=0.039) and hypoalbuminemia at transplant (HR=2.96, 95%CI 1.14-7.68, P=0.026) were independent risk factors for the prognosis of allogeneic hematopoietic stem cell transplantation in pediatric patients with CID. Conclusions: Allogeneic hematopoietic stem cell transplantation is an effective treatment for CID. The medical history of sepsis and hypoalbuminemia at transplant were risk factors for prognosis. Enhancing infection prevention and nutritional intervention before transplant can improve patient prognosis.

Inmunodeficiencia combinada grave: Presentación de un caso / Severe Combined Immunodeficiency: Case presentation

Introducción: Las inmunodeficiencias primarias son un grupo heterogéneo de trastornos hereditarios ocasionados por defectos del desarrollo o función del sistema inmunológico. Las inmunodeficiencias combinadas graves constituyen el 15 por ciento de las inmunodeficiencias primarias, son graves y los pacientes rara vez sobreviven sin tratamiento después del primer año de vida, lo que obliga a un diagnóstico y tratamiento oportuno. Objetivo: Presentar un caso con inmunodeficiencia combinada grave, condición reportada con poca frecuencia y evolución desfavorable. Presentación de caso: Lactante masculino de seis meses con antecedentes de cuatro ingresos en Unidad de Terapia Intensiva por infecciones, el último por bronconeumonía bilateral. Fue valorado por Inmunología y se diagnosticó una inmunodeficiencia combinada grave por la clínica (infecciones por gérmenes oportunistas: Candida albicans y Pneumocistys jirovecii) y estudios inmunológicos (con disminución de los anticuerpos IgG: 0,02 g/L, IgM: 0.1 g/L e IgA: 0 g/L), subpoblaciones linfocitarias disminuidas (CD3/CD4: 9,3 por ciento, CD3/CD8: 5,6 por ciento, CD19: 0 por ciento, CD 16: 0,73 por ciento), además hipoplasia tímica severa (120 mm2). Se inició tratamiento con antimicrobianos de amplio espectro e inmunoestimulantes (Hebertrans y Biomodulina T). Evolucionó desfavorablemente y falleció por shock séptico. Conclusiones: La inmunodeficiencia combinada grave es una emergencia pediátrica que debe tenerse en cuenta en pacientes con antecedentes de infecciones recurrentes, es vital conocer las manifestaciones clínicas tempranas que permitan la sospecha diagnóstica, haciendo uso de todas las herramientas disponibles para su confirmación. El diagnóstico precoz es el elemento clave para la reducción de la morbilidad y mortalidad relacionada con estas enfermedades(AU)

Introduction: Primary Immunodeficiencies are a heterogeneous group of inherited disorders caused by defects in development or function of the immune system. Severe Combined Immunodeficiencies constitute 15% of the primary immunodeficiencies, they are acute and patients rarely survive without treatment after the first year of life, requiring a quick diagnosis and treatment. Objective: To present a case on Severe Combined Immunodeficiency, a condition infrequently reported and with unfavorable evolution. Case presentation: Six-month-old male infant with a history of four admissions to the Intensive Care Unit due to infections, in the latter one due to bilateral bronchopneumonia. He was evaluated by Immunology and a Severe Combined Immunodeficiency was diagnosed by the clinic (infections by opportunistic germs: Candida albicans and Pneumocistys jirovecii) and immunological studies (with a decrease in IgG antibodies: 0.02 g/L, IgM: 0.1 g/L and IgA: 0 g/L), decreased lymphocyte subpopulations (CD3/CD4: 9.3 percent, CD3/CD8: 5.6 percent, CD19: 0 percent, CD 16: 0.73 percent), in addition to severe thymic hypoplasia (120 mm2). Treatment with broad spectrum antimicrobials and immunostimulants (Hebertrans and Biomodulin T) was started. He evolved unfavorably and died of septic shock. Conclusions: Severe Combined Immunodeficiency is a pediatric emergency that must be taken into account in patients with a history of recurrent infections, it is vital to know the early clinical manifestations that allow a suspected diagnosis, making use of all the available tools for its confirmation. Early diagnosis is the key element in reducing morbidity and mortality related to these diseases(AU)

Hematopoietic Cell Transplantation for Severe Combined Immunodeficiency Patients: a Japanese Retrospective Study.

PURPOSE: Hematopoietic cell transplantation (HCT) is a curative therapy for patients with severe combined immunodeficiency (SCID). Here, we conducted a nationwide study to assess the outcome of SCID patients after HCT in Japan. METHODS: A cohort of 181 SCID patients undergoing their first allogeneic HCT in 1974-2016 was studied by using the Japanese national database (Transplant Registry Unified Management Program, TRUMP). RESULTS: The 10-year overall survival (OS) of the patients who received HCT in 2006-2016 was 67%. Umbilical cord blood (UCB) transplantation was performed in 81 patients (45%). The outcomes of HCT from HLA-matched UCB (n = 21) and matched sibling donors (n = 22) were comparable, including 10-year OS (91% vs. 91%), neutrophil recovery (cumulative incidence at 30 days, 89% vs. 100%), and platelet recovery (cumulative incidence at 60 days, 89% vs. 100%). Multivariate analysis of the patients who received HCT in 2006-2016 demonstrated that the following factors were associated with poor OS: bacterial or fungal infection at HCT (hazard ratio (HR): 3.8, P = 0.006), cytomegalovirus infection prior to HCT (HR: 9.4, P = 0.03), ≥ 4 months of age at HCT (HR: 25.5, P = 0.009), and mismatched UCB (HR: 19.8, P = 0.01). CONCLUSION: We showed the potential of HLA-matched UCB as a donor source with higher priority for SCID patients. We also demonstrated that early age at HCT without active infection is critical for a better prognosis, highlighting the importance of newborn screening for SCID.

Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients.

PURPOSE: Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2. METHODS: We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS). RESULTS: Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT. CONCLUSION: HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency. CLINICAL IMPLICATIONS: HCT is a definitive cure for DADA2 with > 95% survival.

Single-Center Study of 72 Patients with Severe Combined Immunodeficiency: Clinical and Laboratory Features and Outcomes.

Severe combined immunodeficiency is an inborn error of immunity characterized by impairments in the numbers and functions of T and B lymphocytes due to various genetic causes, and if it remains untreated, patients succumb to infections during the first 2 years of life. PURPOSE AND METHODS: This study reported retrospective data from 72 infants diagnosed with SCID including their major clinical features, HSCT characteristics, and outcomes over a 20-year period (1997-2017). RESULTS: Sixty-one of 72 SCID patients in the study underwent HSCT from 1997 to 2017. Median ages at the time of diagnosis and transplantation were 3.5 months and 5 months, respectively. Consanguinity was present in 68% of the patients, and T - B - NK + phenotype was predominantly identified. The overall survival was 80.3% over a 20-year period. However, the patients transplanted during an active infection had a lower survival rate of 73.9% compared to 100% for patients transplanted infection-free or with a previous infection that had resolved. The survival rate was significantly higher among recipients of HLA-identical transplants (92.9%), compared to recipients of mismatched related transplants (70%). The overall survival increased from 50 (1997-2006) to 85% (2007-2017) during the last 10 years. CONCLUSIONS: This is one of the largest single-center studies in Turkey with extensive experience about SCID patients. Early diagnosis of SCID patients before the onset of an infection and early transplantation are shown to be extremely important factors affecting the outcome and increasing the survival regardless of the donor type based on the results of this study.

Review: Why screen for severe combined immunodeficiency disease?

Newborn screening for severe combined immunodeficiency (SCID) is now routinely performed in many countries across Europe and around the world. The number of T-cell receptor excision circles (TRECs) reflects T cell levels. TREC quantification is possible using dried blood spot (DBS) samples already collected from newborns to screen for other conditions. This method is very sensitive and highly specific. Data in the literature show that the survival rate for children with SCID is much higher when the disease is detected through early screening, as opposed to a later diagnosis. Newborns diagnosed with SCID may receive the appropriate care quickly, before the onset of serious infectious complications, which raises survival rates, improves quality of life, and limits side effects and treatment costs. At the request of the French Ministry of Health, France's National Authority for Health (Haute Autorité de Santé) is expected to issue recommendations on this topic soon. The nationwide DEPISTREC study, involving 48 maternity units across France, showed that routine SCID screening is feasible and effective. Such screening offers the additional benefit of also diagnosing non-SCID lymphopenia within the infant population.

Incidence of SCID in Germany from 2014 to 2015 an ESPED* Survey on Behalf of the API*** Erhebungseinheit für Seltene Pädiatrische Erkrankungen in Deutschland (German Paediatric Surveillance Unit) ** Arbeitsgemeinschaft Pädiatrische Immunologie.

PURPOSE: Severe combined immunodeficiencies (SCID) are a heterogeneous group of fatal genetic disorders, in which the immune response is severely impaired. SCID can be cured if diagnosed early. We aim to determine the incidence of clinically defined SCID cases, acquire data of reported cases and evaluate their possible prediction by newborn screening, before introduction of a general screening program in Germany. METHODS: The German Surveillance Unit for rare Paediatric Diseases (ESPED) prospectively queried the number of incident SCID cases in all German paediatric hospitals in 2014 and 2015. Inclusion criteria were (1) opportunistic or severe infections or clinical features associated with SCID (failure to thrive, lacking thymus or lymphatic tissue, dysregulation of the immune system, graft versus host reaction caused by maternal T cells), (2) dysfunctional T cell immunity or proof of maternal T cells and (3) exclusion of a secondary immunodeficiency such as human immunodeficiency virus (HIV) infection. In a capture-recapture analysis, cases were matched with cases reported to the European Society for Immunodeficiencies (ESID). RESULTS: Fifty-eight patients were initially reported to ESPED, 24 reports could be confirmed as SCID, 21 patients were less than 1 year old at time of diagnosis. One SCID case was reported to ESID only. The estimated incidence of SCID in Germany is 1.6/100,000 (1:62,500) per year in children less than 1 year of age. Most patients reported were symptomatic and mortality in regard to reported outcome was high (29% (6/22)). The majority of incident SCID cases were considered to be probably detectable by newborn screening. CONCLUSIONS: SCID is a rare disease with significant mortality. Newborn screening may give the opportunity to improve the prognosis in a significant number of children with SCID.

Genetic mutations and immunological features of severe combined immunodeficiency patients in Iran.

BACKGROUND: Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency disorders that is characterized by impaired early T lymphocyte differentiation and is variably associated with abnormal development of other lymphocyte lineages. SCID can be caused by mutations in more than 20 different genes. Molecular diagnosis in SCID patients contributes to genetic counseling, prenatal diagnosis, treatment modalities, and overall prognosis. In this cohort, the clinical, laboratory and genetic data related to Iranian SCID patients were comprehensively evaluated and efficiency of stepwise sequencing methods approach based on immunophenotype grouping was investigated METHODS: Clinical and laboratory data from 242 patients with SCID phenotype were evaluated. Molecular genetic analysis methods including Sanger sequencing, targeted gene panel and whole exome sequencing were performed on 62 patients. RESULTS: Mortality rate was 78.9% in the cohort with a median follow-up of four months. The majority of the patients had a phenotype of T-NK-B+ (34.3%) and the most severe clinical manifestation and highest mortality rate were observed in T-NK-B- SCID cases. Genetic mutations were confirmed in 50 patients (80.6%), of which defects in recombination-activating genes (RAG1 and RAG2) were found in 16 patients (32.0%). The lowest level of CD4+ and CD8+ cells were observed in patients with ADA deficiency (p = 0.026) and IL2RG deficiency (p = 0.019), respectively. CONCLUSION: Current findings suggest that candidate gene approach based on patient's immunophenotype might accelerate molecular diagnosis of SCID patients. Candidate gene selection should be done according to the frequency of disease-causing genes in different populations. Targeted gene panel, WES and WGS methods can be used for the cases which are not diagnosed using this method.

Clinical Features and HSCT Outcome for SCID in Turkey.

Severe combined immunodeficiency (SCID) is the most serious PID, characterized by T cell lymphopenia and lack of antigen-specific T cell and B cell immune responses, inevitably leading to death within the first year of life if hematopoietic stem cell transplantation (HSCT) is not performed. PURPOSE AND METHODS: Since SCID is a common type of PID with an estimated incidence of 1/10.000 in Turkey, a retrospective analysis of HSCT characteristics, survival, immune recovery, and the major clinical features of SCID prior to HSCT is the aim of this multi-transplant center-based analysis. RESULTS: A total of 234 SCID patients transplanted between the years 1994 and 2014 were included in the study. Median age at diagnosis was 5 months, at transplantation, 7 months, B- phenotype and RAGs were the most common defects among others. Immune phenotype did not seem to have an effect on survival rate (p > 0.05), Immunoglobulin (Ig) requirement following HSCT did not differ between B+ and B- phenotypes (p > 0.05). Overall survival rate was 65.7% over a period of 20 years. It increased from 54% (1994-2004) to 69% (p = 0.052) during the last 10 years (2005-2014). Ten-year survival after HSCT has improved over time although the difference was not significant. Infection at the time of transplantation (p = 0.006), mismatched related donor (MMRD) (haploidentical parents), and matched unrelated donor (MUD) donor transplants p < 0.001 were the most important factors, significantly affecting the outcome. CONCLUSIONS: This is the first multicenter study with the largest data obtained from transplanted SCID patients in Turkey. Early diagnosis with newborn screening (NBS) together with emerging referrals, treatment by transplantation centers, and specialized teams are mandatory in countries with high parental consanguinity such as Turkey.

Survival Trends in Infants Undergoing Allogeneic Hematopoietic Cell Transplant.

Importance: Studies demonstrating improved survival after allogeneic hematopoietic cell transplant generally exclude infants. Objective: To analyze overall survival trends and other outcomes among infants who undergo allogeneic hematopoietic cell transplant. Design, Setting, and Participants: In this cohort study, we used time-trend analysis to evaluate 3 periods: 2000 through 2004, 2005 through 2009, and 2010 through 2014. The study was conducted in a multicenter setting through the Center for International Blood and Marrow Transplant Research, which is made up of a voluntary working group of more than 450 transplant centers worldwide. Two groups of infants aged 1 year or younger in 2 cohorts were included: those with malignant conditions, such as leukemia, and those with nonmalignant disorders, including immunodeficiencies. Data analysis was conducted from July 2017 to December 2018. Exposures: Allogeneic hematopoietic cell transplant. Main Outcomes and Measures: Survival trends, disease relapse, and toxicity. Results: A total of 2498 infants with a median age of 7 months (range, <1-12 months) were included. In the nonmalignant cohort (n = 472), survival rates improved from the first to the second period (hazard ratio, 0.77 [95% CI, 0.63-0.93]; P = .007) but did not change after 2004. Compared with infants with nonmalignant diseases (n = 2026; 3-year overall survival: 2000-2004, 375/577 [65.0%]; 2005-2009, 503/699 [72.0%]; and 2010-2014, 555/750 [74.0%]), those with malignant conditions had poorer survival rates, without improvement over time (3-year overall survival: 2000-2004, 109/199 [54.8%]; 2005-2009, 104/161 [64.6%]; and 2010-2014, 66/112 [58.9%]). From 2000 through 2014, relapse rates increased in infants with malignant conditions (3-year relapse rate: 2000-2004, 19% [95% CI, 14%-25%]; 2005-2009, 23% [95% CI, 17%-30%]; 2010-2014, 36% [95% CI, 27%-46%]; P = .01). Sinusoidal obstruction syndrome was frequent, occurring with a cumulative incidence of 13% (95% CI, 11%-16%) of infants with nonmalignant diseases and 32% (95% CI, 22%-42%) of those with malignant diseases. Generally, recipients of human leukocyte antigen-identical sibling bone marrow grafts had the best outcomes. Conclusions and Relevance: Survival rates have not improved for infants with malignant diseases over the 15-year study period. Infants with nonmalignant diseases had improved survival rates in the earlier but not the later study period. Higher relapses for the malignant cohort and toxicities for all infants remain significant challenges. Strategies to reduce relapse and toxicity and optimize donor and graft selection may improve outcomes in the future.

SCID genotype and 6-month posttransplant CD4 count predict survival and immune recovery.

The Primary Immune Deficiency Treatment Consortium (PIDTC) performed a retrospective analysis of 662 patients with severe combined immunodeficiency (SCID) who received a hematopoietic cell transplantation (HCT) as first-line treatment between 1982 and 2012 in 33 North American institutions. Overall survival was higher after HCT from matched-sibling donors (MSDs). Among recipients of non-MSD HCT, multivariate analysis showed that the SCID genotype strongly influenced survival and immune reconstitution. Overall survival was similar for patients with RAG, IL2RG, or JAK3 defects and was significantly better compared with patients with ADA or DCLRE1C mutations. Patients with RAG or DCLRE1C mutations had poorer immune reconstitution than other genotypes. Although survival did not correlate with the type of conditioning regimen, recipients of reduced-intensity or myeloablative conditioning had a lower incidence of treatment failure and better T- and B-cell reconstitution, but a higher risk for graft-versus-host disease, compared with those receiving no conditioning or immunosuppression only. Infection-free status and younger age at HCT were associated with improved survival. Typical SCID, leaky SCID, and Omenn syndrome had similar outcomes. Landmark analysis identified CD4+ and CD4+CD45RA+ cell counts at 6 and 12 months post-HCT as biomarkers predictive of overall survival and long-term T-cell reconstitution. Our data emphasize the need for patient-tailored treatment strategies depending upon the underlying SCID genotype. The prognostic significance of CD4+ cell counts as early as 6 months after HCT emphasizes the importance of close follow-up of immune reconstitution to identify patients who may need additional intervention to prevent poor long-term outcome.

Antiviral combination therapy for cytomegalovirus infection in high-risk infants.

BACKGROUND: Cytomegalovirus (CMV) infection is a major risk factor for mortality in infants with severe combined immunodeficiency (SCID) and other profound immune defects. Specific antiviral therapy must be initiated early and aggressively because of the potential for antiviral resistance, rapid dissemination and poor transplant outcomes. Combination antiviral therapy is routinely administered for some viral infections, but the value of this approach for the treatment of CMV is unclear. Here we explore a strategy of initial combination therapy for high-risk infants with CMV infection. METHODS: We reviewed medical records of infants ≤6 months of age hospitalized between 2007-2015 who received ganciclovir (GCV) or foscarnet (FOS) monotherapy or initial combination GCV + FOS for CMV disease. The combination therapy group consisted of severely immunocompromised infants being considered for haematopoietic cell transplantation (HCT). RESULTS: Four patients received initial combination antiviral therapy and 26 patients received initial monotherapy during the study period. Combination antiviral recipients demonstrated initial improvement in viraemia and two of three who continued with this therapy survived the infection. Clinically significant resistance mutations did not emerge. Toxicity was common; neutropenia, thrombocytopenia and electrolyte abnormalities were the most frequent adverse events in both groups. Creatinine elevation was uncommon in both groups. CONCLUSIONS: Combination GCV + FOS therapy may be a safe alternative to monotherapy in high-risk infants, especially those who are pre-transplant with primary immune deficiency syndromes and high viral loads.

ADA Deficiency: Evaluation of the Clinical and Laboratory Features and the Outcome.

INTRODUCTION: Adenosine deaminase (ADA) deficiency is an autosomal recessive primary immunodeficiency. It results in the intracellular accumulation of toxic metabolites which have effects particularly on lymphocytes and the brain. The aim of this study was to evaluate the outcome of 13 ADA-deficient patients. We planned to evaluate their clinical and laboratory findings before and after enzyme replacement therapy (ERT), allogeneic hematopoietic stem cell transplantation (aHSCT), and hematopoietic stem cell gene therapy (HSCGT). METHODS: Measurement of ADA enzyme activity and metabolites and sequencing of the ADA gene were performed in most of the patients with ADA deficiency. One of the patients with late-onset ADA deficiency was diagnosed by the help of primary immunodeficiency panel screening. RESULTS: Ten out of 13 patients were diagnosed as SCID, while 3 out of 13 were diagnosed as delayed-/late-onset ADA deficiency. Late-onset ADA deficiency patients had clinical and laboratory findings of combined immunodeficiency (CID). Eight patients with ADA-SCID were found to have higher levels of ADA metabolite (dAXP%) (62.1% (34.6-71.9)) than 3 patients with delayed-/late-onset ADA deficiency (6.9% (2.1-8.9). All but one patient with SCID had T-B-NK- phenotype, one had T-B-NK+ phenotype. Genetic defect was documented in 11 patients. Four out of 11 patients had compound heterozygous defects. Three out of 4 patients with compound heterozygous defects had delayed-onset/late-onset ADA deficiency. Seven out of 11 patients with SCID had homozygous defects. Five out of 7 had the same homozygous indel frameshift mutation (c.955-959delGAAGA) showing a founder effect. There were two novel splice site defects: one (IVS10+2T>C) was heterozygous in a patient with late-onset ADA deficiency, and the other was homozygous (IVS2delT+2) in a SCID patient. Other defects were missense defects. Nine out of 13 patients were put on pegylated ADA ERT. Four out of six patients were transplanted without using a conditioning regimen. HSCGT was performed to one of the patients. CONCLUSION: The genetic diagnosis of SCID is utmost important. There is a chance to give ERT before the definitive therapy if the patient with SCID/CID has ADA deficiency. Although ERT was insufficient to restore a normal immune function in ADA-SCID patients, it was useful to improve and stabilize the clinical status before curative therapy (aHSCT/HSCGT). Enzyme replacement therapy was successful in patients with late-/delayed-onset ADA deficiency who presented with the features of combined immunodeficiency. Gastrointestinal polyposis in a patient with late-onset ADA deficiency may be an association or a coincidental finding. Intermittent neurodevelopmental evaluation especially for hearing impairment should be performed in most of the ADA-deficient patients. This may alleviate the speech delay and cognitive abnormalities which may be observed in the follow-up.

Immune reconstitution and survival of 100 SCID patients post-hematopoietic cell transplant: a PIDTC natural history study.

The Primary Immune Deficiency Treatment Consortium (PIDTC) is enrolling children with severe combined immunodeficiency (SCID) to a prospective natural history study. We analyzed patients treated with allogeneic hematopoietic cell transplantation (HCT) from 2010 to 2014, including 68 patients with typical SCID and 32 with leaky SCID, Omenn syndrome, or reticular dysgenesis. Most (59%) patients were diagnosed by newborn screening or family history. The 2-year overall survival was 90%, but was 95% for those who were infection-free at HCT vs 81% for those with active infection (P = .009). Other factors, including the diagnosis of typical vs leaky SCID/Omenn syndrome, diagnosis via family history or newborn screening, use of preparative chemotherapy, or the type of donor used, did not impact survival. Although 1-year post-HCT median CD4 counts and freedom from IV immunoglobulin were improved after the use of preparative chemotherapy, other immunologic reconstitution parameters were not affected, and the potential for late sequelae in extremely young infants requires additional evaluation. After a T-cell-replete graft, landmark analysis at day +100 post-HCT revealed that CD3 < 300 cells/µL, CD8 < 50 cells/µL, CD45RA < 10%, or a restricted Vß T-cell receptor repertoire (<13 of 24 families) were associated with the need for a second HCT or death. In the modern era, active infection continues to pose the greatest threat to survival for SCID patients. Although newborn screening has been effective in diagnosing SCID patients early in life, there is an urgent need to identify validated approaches through prospective trials to ensure that patients proceed to HCT infection free. The trial was registered at www.clinicaltrials.gov as #NCT01186913.

Long-Term Outcome of Adenosine Deaminase-Deficient Patients-a Single-Center Experience.

PURPOSE: Inherited defects in the adenosine deaminase (ADA) enzyme can cause severe combined immune deficiency (SCID) and systemic abnormalities. Management options for ADA-deficient patients include enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), and gene therapy (GT). Here, we describe the long-term benefits of these treatments. METHODS: Survival, infections, systemic sequelae, and laboratory assessments were recorded for all ADA-deficient SCID patients, managed at a single center since 1985, who survived 5 or more years following treatment. RESULTS: Of 20 ADA-deficient patients, the 8 (40%) who survived 5 or more years (range 6-29.5 years, median 14 years) were included in the study. Among the long-term survivors, two patients were treated exclusively with ERT, five underwent HSCT (three from HLA-matched sibling donors, two from HLA-mismatched related donors), and one received GT. The long-term survivors often suffered from recurrent respiratory infections; however, opportunistic infections occurred in only one patient. Systemic sequelae included lung disease such as bronchiectasis and asthma (four patients), neurologic abnormalities (six patients), metabolic disturbances (two patients), allergy and autoimmunity (six patients), and neoplasms (three patients). Normal CD4+ T cell numbers and function, as well as antibody production, were usually observed after HSCT and GT, but not after ERT. Late deaths occurred in two patients at 15 and 25 years after HSCT, respectively, and were attributed to respiratory failure. CONCLUSIONS: ADA-deficient patients commonly suffer from long-term complications, emphasizing the need for improved management and for multi-disciplinary follow-up.

Reticular dysgenesis: international survey on clinical presentation, transplantation, and outcome.

Reticular dysgenesis (RD) is a rare congenital disorder defined clinically by the combination of severe combined immunodeficiency (SCID), agranulocytosis, and sensorineural deafness. Mutations in the gene encoding adenylate kinase 2 were identified to cause the disorder. Hematopoietic stem cell transplantation (HSCT) is the only option to cure this otherwise fatal disease. Retrospective data on clinical presentation, genetics, and outcome of HSCT were collected from centers in Europe, Asia, and North America for a total of 32 patients born between 1982 and 2011. Age at presentation was <4 weeks in 30 of 32 patients (94%). Grafts originated from mismatched family donors in 17 patients (55%), from matched family donors in 6 patients (19%), and from unrelated marrow or umbilical cord blood donors in 8 patients (26%). Thirteen patients received secondary or tertiary transplants. After transplantation, 21 of 31 patients were reported alive at a mean follow-up of 7.9 years (range: 0.6-23.6 years). All patients who died beyond 6 months after HSCT had persistent or recurrent agranulocytosis due to failure of donor myeloid engraftment. In the absence of conditioning, HSCT was ineffective to overcome agranulocytosis, and inclusion of myeloablative components in the conditioning regimens was required to achieve stable lymphomyeloid engraftment. In comparison with other SCID entities, considerable differences were noted regarding age at presentation, onset, and type of infectious complications, as well as the requirement of conditioning prior to HSCT. Although long-term survival is possible in the presence of mixed chimerism, high-level donor myeloid engraftment should be targeted to avoid posttransplant neutropenia.

Long-term outcome of hematopoietic stem cell transplantation for IL2RG/JAK3 SCID: a cohort report.

Hematopoietic stem cell transplantation (HSCT) cures the T-lymphocyte, B-lymphocyte, and natural killer (NK)-cell differentiation defect in interleukin-2 γ-chain receptor (IL2RG)/JAK3 severe combined immunodeficiency (SCID). We evaluated long-term clinical features, longitudinal immunoreconstitution, donor chimerism, and quality of life (QoL) of IL2RG/JAK3 SCID patients >2 years post-HSCT at our center. Clinical data were collated and patients/families answered PedsQL Generic Core Scale v4.0 questionnaires. We performed longitudinal analyses of CD3+, CD4+ naive T-lymphocyte, CD19+, and NK-cell numbers from pretransplant until 15 years posttransplant. Thirty-one of 43 patients (72%) survived. Median age at last follow-up was 10 years (range, 2-25 years). Twenty-one (68%) had persistent medical issues, mainly ongoing immunoglobulin replacement (14; 45%), cutaneous viral warts (7; 24%), short stature (4; 14%), limb lymphoedema (3; 10%), and bronchiectasis (2; 7%). Lung function was available and normal for 6 patients. Longitudinal analysis demonstrated sustained CD3+, CD19+, and NK-cell output 15 years post-HSCT. CD4+ naive lymphocyte numbers were better in conditioned vs unconditioned recipients (P, .06). B-lymphocyte and myeloid chimerism were highly correlated (ρ, 0.98; P < .001). Low-toxicity myeloablative conditioning recipients have better B-lymphocyte/myeloid chimerism and are free from immunoglobulin replacement therapy. IL2RG/JAK3 SCID survivors free from immunoglobulin replacement have normal QoL.

Update on the safety and efficacy of retroviral gene therapy for immunodeficiency due to adenosine deaminase deficiency.

Adenosine deaminase (ADA) deficiency is a rare, autosomal-recessive systemic metabolic disease characterized by severe combined immunodeficiency (SCID). The treatment of choice for ADA-deficient SCID (ADA-SCID) is hematopoietic stem cell transplant from an HLA-matched sibling donor, although <25% of patients have such a donor available. Enzyme replacement therapy (ERT) partially and temporarily relieves immunodeficiency. We investigated the medium-term outcome of gene therapy (GT) in 18 patients with ADA-SCID for whom an HLA-identical family donor was not available; most were not responding well to ERT. Patients were treated with an autologous CD34(+)-enriched cell fraction that contained CD34(+) cells transduced with a retroviral vector encoding the human ADA complementary DNA sequence (GSK2696273) as part of single-arm, open-label studies or compassionate use programs. Overall survival was 100% over 2.3 to 13.4 years (median, 6.9 years). Gene-modified cells were stably present in multiple lineages throughout follow up. GT resulted in a sustained reduction in the severe infection rate from 1.17 events per person-year to 0.17 events per person-year (n = 17, patient 1 data not available). Immune reconstitution was demonstrated by normalization of T-cell subsets (CD3(+), CD4(+), and CD8(+)), evidence of thymopoiesis, and sustained T-cell proliferative capacity. B-cell function was evidenced by immunoglobulin production, decreased intravenous immunoglobulin use, and antibody response after vaccination. All 18 patients reported infections as adverse events; infections of respiratory and gastrointestinal tracts were reported most frequently. No events indicative of leukemic transformation were reported. Trial details were registered at www.clinicaltrials.gov as #NCT00598481.