RT Journal Article T1 Differential Biological Role of CD3 Chains Revealed by Human Immunodeficiencies A1 Recio Hoyas, María José A1 Miguel Angel Moreno Pelayo, A1 Sara S. Kiliç, A1 Alberto C. Guardo, A1 Ozden Sanal, A1 Allende Martínez, Luis Miguel A1 Verónica Pérez Flores, A1 Angeles Mencía, A1 Silvia Modamio Høybjør, A1 Elena Seoane, A1 Regueiro González-Barros, José Ramón AB The biological role in vivo of the homologous CD3γ and δ invariant chains within the human TCR/CD3 complex is a matter of debate, as murine models do not recapitulate human immunodeficiencies. We have characterized, in a Turkish family, two new patients with complete CD3γ deficiency and SCID symptoms and compared them with three CD3γ-deficient individuals belonging to two families from Turkey and Spain. All tested patients shared similar immunological features such as a partial TCR/CD3 expression defect, mild αβ and γδ T lymphocytopenia, poor in vitro proliferative responses to Ags and mitogens at diagnosis, and very low TCR rearrangement excision circles and CD45RA+ αβ T cells. However, intrafamilial and interfamilial clinical variability was observed in patients carrying the same CD3G mutations. Two reached the second or third decade in healthy conditions, whereas the other three showed lethal SCID features with enteropathy early in life. In contrast, all reported human complete CD3δ (or CD3ε) deficiencies are in infants with life-threatening SCID and very severe αβ and γδ T lymphocytopenia. Thus, the peripheral T lymphocyte pool was comparatively well preserved in human CD3γ deficiencies despite poor thymus output or clinical outcome. We propose a CD3δ ≫ CD3γ hierarchy for the relative impact of their absence on the signaling for T cell production in humans. PB American Association of Inmunology SN 0022-1767 SN 1550-6606 YR 2007 FD 2007-02-15 LK https://hdl.handle.net/20.500.14352/98940 UL https://hdl.handle.net/20.500.14352/98940 LA eng NO Recio MJ, Moreno-Pelayo MA, Kiliç SS, Guardo AC, Sanal O, Allende LM, Pérez-Flores V, Mencía A, Modamio-Høybjør S, Seoane E, Regueiro JR. Differential biological role of CD3 chains revealed by human immunodeficiencies. J Immunol. 2007 Feb 15;178(4):2556-64. doi: 10.4049/jimmunol.178.4.2556. PMID: 17277165. NO Ministerio de Educación y Ciencia NO Ministerio de Ciencia y Tecnología NO Comunidad Autónoma de Madrid NO Mutua Madrileña DS Docta Complutense RD 30 sept 2024