biostudies-literatureBosticardo MIntramural NIH HHSTelethonNIAID NIH HHSNCI NIH HHS2611-2616https://www.ebi.ac.uk/biostudies/studies/S-EPMC7322962biostudies-literatureUnknown4(12)The study of early T-cell development in humans is challenging because of limited availability of thymic samples and the limitations of in vitro T-cell differentiation assays. We used an artificial thymic organoid (ATO) platform generated by aggregating a DLL4-expressing stromal cell line (MS5-hDLL4) with CD34+ cells isolated from bone marrow or mobilized peripheral blood to study T-cell development from CD34+ cells of patients carrying hematopoietic intrinsic or thymic defects that cause T-cell lymphopenia. We found that AK2 deficiency is associated with decreased cell viability and an early block in T-cell development. We observed a similar defect in a patient carrying a null IL2RG mutation. In contrast, CD34+ cells from a patient carrying a missense IL2RG mutation reached full T-cell maBlood advancesArtificial thymic organoids represent a reliable tool to study T-cell differentiation in patients with severe T-cell lymphopenia.PMC7322962ZIA AI001222TGT16E02P30 CA016042U54 AI082973Gardner CLDeRavin SSBosticardo MCrooks GMSeet CSMontel-Hagen AHartog NSacchetti NMalech HLCalzoni EDraper DHolland SMDelmonte OMKohn DBGungor TPala FVilla AGarabedian EKKawai TNotarangelo LDFreeman AFBergerson JREDobbs KWeinacht KGMarkert MLfalseArtificial thymic organoids represent a reliable tool to study T-cell differentiation in patients with severe T-cell lymphopenia.The study of early T-cell development in humans is challenging because of limited availability of thymic samples and the limitations of in vitro T-cell differentiation assays. We used an artificial thymic organoid (ATO) platform generated by aggregating a DLL4-expressing stromal cell line (MS5-hDLL4) with CD34+ cells isolated from bone marrow or mobilized peripheral blood to study T-cell development from CD34+ cells of patients carrying hematopoietic intrinsic or thymic defects that cause T-cell lymphopenia. We found that AK2 deficiency is associated with decreased cell viability and an early block in T-cell development. We observed a similar defect in a patient carrying a null IL2RG mutation. In contrast, CD34+ cells from a patient carrying a missense IL2RG mutation reached full T-cell ma2020-01-01T00:00:00Z2020 Jun2025-04-18T17:38:35.84Z2020-07-03T07:08:53ZS-EPMC73229623255628310.1182/bloodadvances.2020001730