Persistent selective T-lymphocytopenia is found both in SCID and congenital athymia. Without molecular diagnosis, it is challenging to determine whether HCT or thymus transplantation ought to be performed. Ex vivo T-lymphopoiesis assays have been proposed to assist clinical decision-making for genetically undefined patients. We investigated 20 T-lymphocytopenic patients, including 13 patients awaiting first-line treatment and 7 patients with failed immune reconstitution after previous HCT or thymus transplantation. Whilst developmental blocks in ex vivo T-lymphopoiesis indicated hematopoietic cell-intrinsic defects, successful T-lymphocyte differentiation required careful interpretation, in conjunction with clinical status, immunophenotyping, and genetic investigations. Of the 20 patients, 13 proceeded to treatment, with successful immune reconstitution observed in 4 of the 6 patients post-HCT and 4 of the 7 patients after thymus transplantation, the latter including two patients who had previously undergone HCT. Whilst further validation and standardization are required, we conclude that assessing ex vivo T-lymphopoiesis during the diagnostic pathway for genetically undefined T-lymphocytopenia improves patient outcomes by facilitating corrective treatment choice.

• MeSH
• buněčná diferenciace MeSH
• dítě MeSH
• imunofenotypizace MeSH
• kojenec MeSH
• lidé MeSH
• lymfopenie * imunologie   MeSH
• lymfopoéza * genetika   MeSH
• mladiství MeSH
• předškolní dítě MeSH
• primární imunodeficience terapie   genetika   imunologie   MeSH
• T-lymfocyty * imunologie   MeSH
• thymus imunologie   MeSH
• transplantace hematopoetických kmenových buněk * metody   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Congenital athymia is a life-limiting disorder due to rare inborn errors of immunity causing impaired thymus organogenesis or abnormal thymic stromal cell development and function. Athymic infants have a T-lymphocyte-negative, B-lymphocyte-positive, natural killer cell-positive immunophenotype with profound T-lymphocyte deficiency and are susceptible to severe infections and autoimmunity. Patients variably display syndromic features. Expanding access to newborn screening for severe combined immunodeficiency and T lymphocytopenia and broad genetic testing, including next-generation sequencing technologies, increasingly facilitate their timely identification. The recommended first-line treatment is allogeneic thymus transplantation, which is a specialized procedure available in Europe and the United States. Outcomes for athymic patients are best with early diagnosis and thymus transplantation before the development of infectious and inflammatory complications. These guidelines on behalf of the European Society for Immunodeficiencies provide a comprehensive review for clinicians who manage patients with inborn thymic stromal cell defects; they offer clinical practice recommendations focused on the diagnosis, investigation, risk stratification, and management of congenital athymia with the aim of improving patient outcomes.

• MeSH
• lidé MeSH
• management nemoci MeSH
• novorozenec MeSH
• syndromy imunologické nedostatečnosti * terapie   diagnóza   imunologie   MeSH
• thymus imunologie   MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• směrnice pro lékařskou praxi MeSH
• Geografické názvy
• Evropa MeSH

BACKGROUND: Newborn screening (NBS) programs for severe combined immunodeficiency facilitate early diagnosis of severe combined immunodeficiency and promote early treatment with hematopoietic stem cell transplantation, resulting in improved clinical outcomes. Infants with congenital athymia are also identified through NBS because of severe T-cell lymphopenia. With the expanding introduction of NBS programs, referrals of athymic patients for treatment with thymus transplantation have recently increased at Great Ormond Street Hospital (GOSH) (London, United Kingdom). OBJECTIVE: We studied the impact of NBS on timely diagnosis and treatment of athymic infants with thymus transplantation at GOSH. METHODS: We compared age at referral and complications between athymic infants diagnosed after clinical presentation (n = 25) and infants identified through NBS (n = 19) who were referred for thymus transplantation at GOSH between October 2019 and February 2023. We assessed whether age at time of treatment influences thymic output at 6 and 12 months after transplantation. RESULTS: The infants referred after identification through NBS were significantly younger and had fewer complications, in particular fewer infections. All deaths occurred in the group of those who did not undergo NBS, including 6 patients before and 2 after thymus transplantation because of preexisting infections. In the absence of significant comorbidities or diagnostic uncertainties, timely treatment was achieved more frequently after NBS. Treatment when younger than age 4 months was associated with higher thymic output at 6 and 12 months after transplantation. CONCLUSION: NBS contributes to earlier recognition of congenital athymia, promoting referral of athymic patients for thymus transplantation before they acquire infections or other complications and facilitating treatment at a younger age, thus playing an important role in improving their outcomes.

• MeSH
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• novorozenecký screening MeSH
• syndromy imunologické nedostatečnosti * MeSH
• těžká kombinovaná imunodeficience * diagnóza   terapie   MeSH
• thymus MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH