RESUMO
BACKGROUND: Massachusetts began newborn screening (NBS) for severe combined immunodeficiency (SCID) using measurement of T-cell receptor excision circles (TRECs) from dried blood spots. OBJECTIVE: We describe developments and outcomes from the first 10 years of this program (February 1, 2009, to January 31, 2019). METHODS: TREC values, diagnostic, and outcome data from all patients screened for SCID were evaluated. RESULTS: NBS of 720,038 infants prompted immunologic evaluation of 237 (0.03%). Of 237, 9 were diagnosed with SCID/leaky SCID (4% of referrals vs 0.001% general population). Another 7 were diagnosed with other combined immunodeficiencies, and 3 with athymia. SCID/leaky SCID incidence was approximately 1 in 80,000, whereas approximately 1 in 51,000 had severe T-cell lymphopenia for which definitive treatment was indicated. All patients with SCID/leaky SCID underwent hematopoietic cell transplant or gene therapy with 100% survival. One patient with athymia underwent successful thymus transplant. No known cases of SCID were missed. Compared with outcomes from the 10 years before SCID NBS, survival trended higher (9 of 9 vs 4 of 7), likely due to a lower rate of infection before treatment. CONCLUSIONS: Our data support a single NBS testing-and-referral algorithm for all gestational ages. Despite lower median TREC values in premature infants, the majority for all ages are well above the TREC cutoff and the algorithm, which selects urgent (undetectable TREC) and repeatedly abnormal TREC values, minimizes referral. We also found that low naïve T-cell percentage is associated with a higher risk of SCID/CID, demonstrating the utility of memory/naïve T-cell phenotyping as part of follow-up flow cytometry.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Imunodeficiência Combinada Severa , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Massachusetts/epidemiologia , Triagem Neonatal , Receptores de Antígenos de Linfócitos T/genética , Imunodeficiência Combinada Severa/diagnóstico , Imunodeficiência Combinada Severa/epidemiologia , Imunodeficiência Combinada Severa/genéticaRESUMO
This report presents the case of a 15-year-old male with severe chronic neutropenia, leukopenia, and persistent tetraploid mosaicism in the bone marrow and peripheral blood. His father had mild neutropenia and bone marrow tetraploidy. Flow cytometric analysis of DNA content peripheral blood showed tetraploidy in 20% of granulocytes and 15% of monocytes. Sequence analysis of the ELA2 gene was normal, but the GFI1 gene exhibited transient appearance of single base changes the coding region and promoter. We speculate that an underlying genetic defect, inherited in an autosomal dominant pattern, leads to both disordered mitosis and neutropenia in this kindred.
Assuntos
Proteínas de Ligação a DNA/genética , Mosaicismo , Neutropenia/congênito , Poliploidia , Fatores de Transcrição/genética , Adolescente , Adulto , Doença Crônica , Genes Dominantes , Granulócitos/ultraestrutura , Humanos , Leucemia/genética , Leucopenia/congênito , Leucopenia/genética , Linfoma Folicular/genética , Masculino , Mitose/genética , Monócitos/ultraestrutura , Mutagênese , Neutropenia/genética , Paraproteinemias/genética , LinhagemRESUMO
Retroviral gene therapy can restore immunity to infants with X-linked severe combined immunodeficiency (XSCID) caused by mutations in the IL2RG gene encoding the common gamma chain (gammac) of receptors for interleukins 2 (IL-2), -4, -7, -9, -15, and -21. We investigated the safety and efficacy of gene therapy as salvage treatment for older XSCID children with inadequate immune reconstitution despite prior bone marrow transplant from a parent. Subjects received retrovirus-transduced autologous peripherally mobilized CD34(+) hematopoietic cells. T-cell function significantly improved in the youngest subject (age 10 years), and multilineage retroviral marking occurred in all 3 children.