Short telomere syndromes cause a primary T cell immunodeficiency
Christa L. Wagner, … , Leo Luznik, Mary Armanios
Christa L. Wagner, … , Leo Luznik, Mary Armanios
Published September 4, 2018
Citation Information: J Clin Invest. 2018;128(12):5222-5234. https://doi.org/10.1172/JCI120216.
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Research Article Aging Genetics

Short telomere syndromes cause a primary T cell immunodeficiency

Abstract

The mechanisms that drive T cell aging are not understood. We report that children and adult telomerase mutation carriers with short telomere length (TL) develop a T cell immunodeficiency that can manifest in the absence of bone marrow failure and causes life-threatening opportunistic infections. Mutation carriers shared T cell–aging phenotypes seen in adults 5 decades older, including depleted naive T cells, increased apoptosis, and restricted T cell repertoire. T cell receptor excision circles (TRECs) were also undetectable or low, suggesting that newborn screening may identify individuals with germline telomere maintenance defects. Telomerase-null mice with short TL showed defects throughout T cell development, including increased apoptosis of stimulated thymocytes, their intrathymic precursors, in addition to depleted hematopoietic reserves. When we examined the transcriptional programs of T cells from telomerase mutation carriers, we found they diverged from older adults with normal TL. Short telomere T cells upregulated DNA damage and intrinsic apoptosis pathways, while older adult T cells upregulated extrinsic apoptosis pathways and programmed cell death 1 (PD-1) expression. T cells from mice with short TL also showed an active DNA-damage response, in contrast with old WT mice, despite their shared propensity to apoptosis. Our data suggest there are TL-dependent and TL-independent mechanisms that differentially contribute to distinct molecular programs of T cell apoptosis with aging.

Authors

Christa L. Wagner, Vidya Sagar Hanumanthu, C. Conover Talbot Jr., Roshini S. Abraham, David Hamm, Dustin L. Gable, Christopher G. Kanakry, Carolyn D. Applegate, Janet Siliciano, J. Brooks Jackson, Stephen Desiderio, Jonathan K. Alder, Leo Luznik, Mary Armanios

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Figure 1

T cell primary immunodeficiency and its complications in telomerase mutation carriers.

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T cell primary immunodeficiency and its complications in telomerase muta...
(A) Telogram showing total lymphocyte TL measured by flow cytometry and FISH of mutation carriers relative to a nomogram of healthy controls. Those who developed opportunistic infections are noted. One TERT mutation carrier (patient 4, Table 1) did not have TL measured, so only 27 of 28 patients studied are plotted. (B and C) Images showing vesicular rash characteristic of VZV reaction (patients 3 and 5 in Table 1, respectively). (D) Brain MRI showing evidence of enhancing periventricular flare (marked by arrows) in a 19-year-old who died from fatal CMV encephalitis (Table 1, patient 4). (E) Chest CT scan image from a patient who developed concurrent P. jiroveci pneumonia that was complicated secondarily by CMV pneumonitis; the latter was treatment refractory and ultimately fatal. (F) Proportion of telomerase mutation carriers with lymphocyte count abnormalities (defined as at least 2 SD below the age-adjusted mean). Low CD4 counts and low IgM levels were the most common anomalies. Data are derived from 17 patients, including 7 from Table 1 for whom the full immune evaluation was available.