Lentiviral Gene Therapy for Artemis-Deficient SCID.

BACKGROUND: The DNA-repair enzyme Artemis is essential for rearrangement of T- and B-cell receptors. Mutations in DCLRE1C, which encodes Artemis, cause Artemis-deficient severe combined immunodeficiency (ART-SCID), which is poorly responsive to allogeneic hematopoietic-cell transplantation. METHODS: We carried out a phase 1-2 clinical study of the transfusion of autologous CD34+ cells, transfected with a lentiviral vector containing DCLRE1C, in 10 infants with newly diagnosed ART-SCID. We followed them for a median of 31.2 months. RESULTS: Marrow harvest, busulfan conditioning, and lentiviral-transduced CD34+ cell infusion produced the expected grade 3 or 4 adverse events. All the procedures met prespecified criteria for feasibility at 42 days after infusion. Gene-marked T cells were detected at 6 to 16 weeks after infusion in all the patients. Five of 6 patients who were followed for at least 24 months had T-cell immune reconstitution at a median of 12 months. The diversity of T-cell receptor ß chains normalized by 6 to 12 months. Four patients who were followed for at least 24 months had sufficient B-cell numbers, IgM concentration, or IgM isohemagglutinin titers to permit discontinuation of IgG infusions. Three of these 4 patients had normal immunization responses, and the fourth has started immunizations. Vector insertion sites showed no evidence of clonal expansion. One patient who presented with cytomegalovirus infection received a second infusion of gene-corrected cells to achieve T-cell immunity sufficient for viral clearance. Autoimmune hemolytic anemia developed in 4 patients 4 to 11 months after infusion; this condition resolved after reconstitution of T-cell immunity. All 10 patients were healthy at the time of this report. CONCLUSIONS: Infusion of lentiviral gene-corrected autologous CD34+ cells, preceded by pharmacologically targeted low-exposure busulfan, in infants with newly diagnosed ART-SCID resulted in genetically corrected and functional T and B cells. (Funded by the California Institute for Regenerative Medicine and the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT03538899.).

Increasing burden of type 2 diabetes in Navajo youth: The SEARCH for diabetes in youth study.

AIM: SEARCH has recently reported that both prevalence and incidence of youth onset type 2 diabetes (YT2D) increased among most US race/ethnic groups in the early 2000s. This study reports on the incidence (2002-2013) and prevalence (2001, 2009) of YT2D in the Navajo Nation among youth age < 20 years from 2001 to 2013. METHODS: SEARCH sought to identify prevalent YT2D cases in 2001 (N = 75) and 2009 (N = 70) and all incident YT2D cases in three periods: 2002 to 2005 (N = 53), 2006 to 2009 (N = 68), and 2010 2013 (N = 90) in Navajo Nation. Denominators were based on the active Indian Health Service user population for eligible health care facilities. Prevalence (per 100 000) and period-specific incidence rates (per 100 000 person-years) were computed for youth aged 10 to 19 years. Changes in prevalence were tested with a two-sided skew-corrected inverted score test, while changes in incidence were tested with Poisson regression. RESULTS: YT2D prevalence was high but stable in 2001 and 2009, overall [146.6 (116.8, 184.0) vs 141.5 (112.0, 178.8), P = .65) and in all subgroups. In contrast, incidence rates increased particularly between the second and third periods overall and in most subgroups by age and by sex. CONCLUSIONS: These data confirm the high burden of YT2D among Navajo youth and suggest an increasing risk in more recent years. However, recent improvements in obesity reduction in this population demonstrate optimism for potential reductions in YT2D in Navajo Nation.

Successful newborn screening for SCID in the Navajo Nation.

Newborn screening (NBS) for severe combined immunodeficiency (SCID) identifies affected infants before the onset of life-threatening infections, permitting optimal treatment. Navajo Native Americans have a founder mutation in the DNA repair enzyme Artemis, resulting in frequent Artemis SCID (SCID-A). A pilot study at 2 Navajo hospitals assessed the feasibility of SCID NBS in this population. Dried blood spots from 1800 infants were assayed by PCR for T-cell receptor excision circles (TRECs), a biomarker for naïve T cells. Starting in February 2012, TREC testing transitioned to standard care throughout the Navajo Area Indian Health Service, and a total of 7900 infants were screened through July 2014. One infant had low TRECs and was diagnosed with non-SCID T lymphopenia, while 4 had undetectable TRECs due to SCID-A, all of whom were referred for hematopoietic cell transplantation. This report establishes the incidence of SCID-A and demonstrates effectiveness of TREC NBS in the Navajo.

Newborn screening for severe combined immunodeficiency in 11 screening programs in the United States.

IMPORTANCE: Newborn screening for severe combined immunodeficiency (SCID) using assays to detect T-cell receptor excision circles (TRECs) began in Wisconsin in 2008, and SCID was added to the national recommended uniform panel for newborn screened disorders in 2010. Currently 23 states, the District of Columbia, and the Navajo Nation conduct population-wide newborn screening for SCID. The incidence of SCID is estimated at 1 in 100,000 births. OBJECTIVES: To present data from a spectrum of SCID newborn screening programs, establish population-based incidence for SCID and other conditions with T-cell lymphopenia, and document early institution of effective treatments. DESIGN: Epidemiological and retrospective observational study. SETTING: Representatives in states conducting SCID newborn screening were invited to submit their SCID screening algorithms, test performance data, and deidentified clinical and laboratory information regarding infants screened and cases with nonnormal results. Infants born from the start of each participating program from January 2008 through the most recent evaluable date prior to July 2013 were included. Representatives from 10 states plus the Navajo Area Indian Health Service contributed data from 3,030,083 newborns screened with a TREC test. MAIN OUTCOMES AND MEASURES: Infants with SCID and other diagnoses of T-cell lymphopenia were classified. Incidence and, where possible, etiologies were determined. Interventions and survival were tracked. RESULTS: Screening detected 52 cases of typical SCID, leaky SCID, and Omenn syndrome, affecting 1 in 58,000 infants (95% CI, 1/46,000-1/80,000). Survival of SCID-affected infants through their diagnosis and immune reconstitution was 87% (45/52), 92% (45/49) for infants who received transplantation, enzyme replacement, and/or gene therapy. Additional interventions for SCID and non-SCID T-cell lymphopenia included immunoglobulin infusions, preventive antibiotics, and avoidance of live vaccines. Variations in definitions and follow-up practices influenced the rates of detection of non-SCID T-cell lymphopenia. CONCLUSIONS AND RELEVANCE: Newborn screening in 11 programs in the United States identified SCID in 1 in 58,000 infants, with high survival. The usefulness of detection of non-SCID T-cell lymphopenias by the same screening remains to be determined.

Epidemiology of invasive Haemophilus influenzae type A disease among Navajo and White Mountain Apache children, 1988-2003.

BACKGROUND: Before the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, rates of H. influenzae disease among Navajo and White Mountain Apache (WMA) children were among the highest reported worldwide. Routine Hib vaccination has significantly reduced rates of Hib disease in these populations. As Hib disease rates decrease to very low levels, there are concerns that non-type b strains of H. influenzae may emerge as more prevalent causes of invasive disease in children. METHODS: We reviewed population-based, active laboratory surveillance data from the period of 1988-2003 for invasive H. influenzae type a (Hia) disease among Navajo and WMA children aged <5 years. Clinical information on cases was collected by chart review. A sample of Hia isolates from Navajo children was typed by pulsed-field gel electrophoresis (PFGE). RESULTS: During 1988-2003, a total of 76 reported cases of invasive Hia disease occurred among Navajo and WMA children. The overall annual incidence was 20.2 cases per 100,000 population aged <5 years. There was no increase in Hia disease rates after Hib vaccination was introduced. The median age of patients was 12 months. Meningitis (50% of cases) was the most common presentation, followed by pneumonia (27.6%). Two children with Hia disease died. PFGE analysis revealed a limited genetic diversity of Hia strains in this population. CONCLUSIONS: Active surveillance data showed high rates of invasive Hia disease among Navajo and WMA children but no increase in the incidence after Hib vaccination was introduced. The presentation of Hia disease is similar to that of Hib disease in the prevaccine era.

Efficacy and safety of seven-valent conjugate pneumococcal vaccine in American Indian children: group randomised trial.

BACKGROUND: Streptococcus pneumoniae is the main cause of invasive bacterial disease in children aged younger than 2 years. Navajo and White Mountain Apache children have some of the highest rates of invasive pneumococcal disease documented in the world. We aimed to assess the safety and efficacy of a seven-valent polysaccharide protein conjugate pneumococcal vaccine (PnCRM7) against such disease. METHODS: In a group-randomised study, we gave this vaccine to children younger than 2 years from the Navajo and White Mountain Apache Indian reservations; meningococcal type C conjugate vaccine (MnCC) served as the control vaccine. Vaccine schedules were determined by age at enrollment. We recorded episodes of invasive pneumococcal disease and serotyped isolates. Analyses were by intention to treat and per protocol. FINDINGS: 8292 children enrolled in the trial. In the per protocol analysis of the primary efficacy group (children enrolled by 7 months of age) there were eight cases of vaccine serotype disease in the controls and two in the PnCRM7 group; in the intention-to-treat analysis we noted 11 cases of vaccine serotype disease in the MnCC control group and two in the PnCRM7 group. After group randomisation had been controlled for, the per protocol primary efficacy of PnCRM7 was 76.8% (95% CI -9.4% to 95.1%) and the intention-to-treat total primary efficacy was 82.6% (21.4% to 96.1%). INTERPRETATION: PnCRM7 vaccine prevents vaccine serotype invasive pneumococcal disease even in a high risk population. Other regions with similar disease burden should consider including this vaccine in the routine childhood vaccine schedule.

Diabetes in Navajo youth: prevalence, incidence, and clinical characteristics: the SEARCH for Diabetes in Youth Study.

OBJECTIVE: To estimate the prevalence and incidence of diabetes, clinical characteristics, and risk factors for chronic complications among Navajo youth, using data collected by the SEARCH for Diabetes in Youth Study (SEARCH study). RESEARCH DESIGN AND METHODS: The SEARCH study identified all prevalent cases of diabetes in 2001 and all incident cases in 2002-2005 among Navajo youth. We estimated denominators with the user population for eligible health care facilities. Youth with diabetes also attended a research visit that included questionnaires, physical examination, blood and urine collection, and extended medical record abstraction. RESULTS: Diabetes is infrequent among Navajo youth aged <10 years. However, both prevalence and incidence of diabetes are high in older youth. Among adolescents aged 15-19 years, 1 in 359 Navajo youth had diabetes in 2001 and 1 in 2,542 developed diabetes annually. The vast majority of diabetes among Navajo youth with diabetes is type 2, although type 1 diabetes is also present, especially among younger children. Navajo youth with either diabetes type were likely to have poor glycemic control, high prevalence of unhealthy behaviors, and evidence of severely depressed mood. Youth with type 2 diabetes had more metabolic factors associated with obesity and insulin resistance (abdominal fat deposition, dyslipidemia, and higher albumin-to-creatinine ratio) than youth with type 1 diabetes. CONCLUSIONS: Our data provide evidence that diabetes is an important health problem for Navajo youth. Targeted efforts aimed at primary prevention of diabetes in Navajo youth and efforts to prevent or delay the development of chronic complications among those with diabetes are warranted.

Predictors of pneumococcal conjugate vaccine immunogenicity among infants and toddlers in an American Indian PnCRM7 efficacy trial.

BACKGROUND: Pneumococcal conjugate vaccines are important for the prevention of serious illness and death among infants. Factors associated with pneumococcal conjugate vaccine immunogenicity have not been explored. METHODS: Children <24 months of age received 2, 3, or 4 doses of 7-valent pneumococcal conjugate vaccine (PnCRM7) or control vaccine depending on age at enrollment. Serum samples were tested for serotype-specific antibodies by enzyme-linked immunosorbant assay. Multiple linear regression was used to determine predictors of immunogenicity. RESULTS: Among 315 PnCRM7-vaccinated subjects and 295 control subjects enrolled at <7 months of age, geometric mean concentrations (GMCs) of antibodies were significantly higher after dose 3 than after dose 2 for all serotypes except type 4. The proportion of subjects with antibody concentrations > or =5.0 micro g/mL was higher for all serotypes, but the proportion with concentrations > or =0.35 micro g/mL was higher only for types 6B and 23F. Three-dose and 2-dose regimens for those 7-11 and 12-23 months of age, respectively, were highly immunogenic. Increased maternal antibody concentrations were associated with reduced responses to dose 1 and 3 but not to dose 4 of PnCRM7. CONCLUSIONS: Maternal antibody is associated with a reduced infant response to PnCRM7 but does not interfere with immune memory. In infants, a third priming dose increases the antibody GMC and the proportion achieving an antibody concentration > or =5.0 micro g/mL but has little impact on the proportion achieving a concentration > or =0.35 micro g/mL.

Prenatal diagnosis and carrier detection for Athabascan severe combined immunodeficiency disease.

OBJECTIVES: Severe combined immunodeficiency disease occurs at a high incidence among Athabascan-speaking Navajo and Apache children (SCIDA). We linked the SCIDA gene to chromosome 10p and recently identified a common nonsense mutation in Artemis/SCIDA. In this study we compared polymorphic markers linked to SCIDA and the point mutation which creates an NspI site on exon 8 for prenatal diagnosis and carrier detection. METHODS: We tested five amniocentesis samples, two cord blood and two blood samples from eight at-risk families using polymorphic DNA markers tightly linked to SCIDA. We amplified the region of exon 8 of Artemis/SCIDA and evaluated the products for the NspI site in each sample plus samples from 30 unrelated healthy Navajos. RESULTS: We correctly predicted that three were affected and six were unaffected. Two of the unaffected appear to be carriers based on our haplotype analysis. Retrospective analysis for the gene mutation confirmed the DNA analysis. Finally, 10% of the normal Navajo controls were carriers. CONCLUSIONS: We demonstrate the feasibility of prenatal diagnosis and carrier detection for SCIDA in the families at risk as well as the availability of a rapid screening test for the SCIDA founder mutation that can be used in all Navajo and Apache newborns and at-risk fetuses.

Hepatitis A incidence and hepatitis a vaccination among American Indians and Alaska Natives, 1990-2001.

OBJECTIVES: We assessed the effect on trends in hepatitis A incidence of the 1996 recommendation for routine hepatitis A vaccination of American Indian/Alaska Native (AIAN) children. METHODS: We examined trends in hepatitis A incidence among AIAN peoples during 1990-2001 and vaccination coverage levels among children on the largest American Indian reservation. RESULTS: Hepatitis A rates among AIANs declined 20-fold during 1997-2001. Declines in hepatitis A incidence occurred among AIANs in reservation and metropolitan areas. Among 1956 children living on the Navajo Nation whose medical records were reviewed, 1508 (77.1%) had received at least one dose of hepatitis A vaccine, and 1020 (52.1%) had completed the vaccine series. CONCLUSIONS: Hepatitis A rates among AIAN peoples have declined dramatically coincident with implementation of routine hepatitis A vaccination of AIAN children.

A founder mutation in Artemis, an SNM1-like protein, causes SCID in Athabascan-speaking Native Americans.

Athabascan SCID (SCIDA) is an autosomal recessive disorder found among Athabascan-speaking Native Americans and is manifested by the absence of both T and B cells (T(-)B(-)NK(+) SCID). We previously mapped the SCIDA gene to a 6.5-cM interval on chromosome 10p. SCIDA fibroblasts were found to have defective coding joint and reduced, but precise signal joint formation during V(D)J recombination. After excluding potential candidate genes, we conducted a combined positional candidate and positional cloning approach leading to the identification of nine novel transcripts in the refined SCIDA region. One of the transcripts showed significant homology with the mouse and yeast SNM1/PSO(2) and was recently reported (Artemis) to be responsible for another T(-)B(-)NK(+) SCID condition (radiation sensitive SCID) in 13 patients of primarily European origin. In our evaluation of this gene, we have identified a unique nonsense mutation in 21 SCIDA patients that is closely correlated to the founder haplotypes that we had previously identified. This nonsense founder mutation results in the truncation of the deduced protein product. The wild-type construct of the primary transcript can effectively complement the defective coding joint and reduced signal joint formation in SCIDA fibroblasts. The above results indicate that this SNM1-like gene (Artemis) is the gene responsible for SCIDA. We also discovered three additional alternative exons and detected at least six alternatively spliced SCIDA variants (SCIDA-V1, 2, 3, 4, 5, and 6) coexisting with the primary transcript in trace amounts. Finally, we found that the SCIDA primary transcript (Artemis) encodes a nuclear protein.