Germline TET2 loss of function causes childhood immunodeficiency and lymphoma

Stremenova Spegarova, Jarmila; Lawless, Dylan; Mohamad, Siti Mardhiana Binti; Engelhardt, Karin R.; Doody, Gina; Shrimpton, Jennifer; Rensing-Ehl, Anne; Ehl, Stephan; Rieux-Laucat, Frederic; Cargo, Catherine; Griffin, Helen; Mikulasova, Aneta; Acres, Meghan; Morgan, Neil V.; Poulter, James A.; Sheridan, Eamonn G.; Chetcuti, Philip; O'Riordan, Sean; Anwar, Rashida; Carter, Clive R.; Przyborski, Stefan; Windebank, Kevin; Cant, Andrew J.; Lako, Majlinda; Bacon, Chris M.; Savic, Sinisa; Hambleton, Sophie

Abstract

Molecular dissection of inborn errors of immunity can help to elucidate the nonredundant functions of individual genes. We studied 3 children with an immune dysregulation syndrome of susceptibility to infection, lymphadenopathy, hepatosplenomegaly, developmental delay, autoimmunity, and lymphoma of B-cell (n = 2) or T-cell (n = 1) origin. All 3 showed early autologous T-cell reconstitution following allogeneic hematopoietic stem cell transplantation. By whole-exome sequencing, we identified rare homozygous germline missense or nonsense variants in a known epigenetic regulator of gene expression: ten-eleven translocation methylcytosine dioxygenase 2 (TET2). Mutated TET2 protein was absent or enzymatically defective for 5-hydroxymethylating activity, resulting in whole-blood DNA hypermethylation. Circulating T cells showed an abnormal immunophenotype including expanded double-negative, but depleted follicular helper, T-cell compartments and impaired Fas-dependent apoptosis in 2 of 3 patients. Moreover, TET2-deficient B cells showed defective class-switch recombination. The hematopoietic potential of patient-derived induced pluripotent stem cells was skewed toward the myeloid lineage. These are the first reported cases of autosomal-recessive germline TET2 deficiency in humans, causing clinically significant immunodeficiency and an autoimmune lymphoproliferative syndrome with marked predisposition to lymphoma. This disease phenotype demonstrates the broad role of TET2 within the human immune system.

Citation

Stremenova Spegarova, J., Lawless, D., Mohamad, S. M. B., Engelhardt, K. R., Doody, G., Shrimpton, J., Rensing-Ehl, A., Ehl, S., Rieux-Laucat, F., Cargo, C., Griffin, H., Mikulasova, A., Acres, M., Morgan, N. V., Poulter, J. A., Sheridan, E. G., Chetcuti, P., O'Riordan, S., Anwar, R., Carter, C. R., …Hambleton, S. (2020). Germline TET2 loss of function causes childhood immunodeficiency and lymphoma. Blood, 136(9), 1055-1066. https://doi.org/10.1182/blood.2020005844

• Journal Article Type: Article
• Online Publication Date: Aug 27, 2020
• Publication Date: 2020-08
• Deposit Date: Sep 10, 2020
• Journal: Blood
• Print ISSN: 0006-4971
• Electronic ISSN: 1528-0020
• Publisher: American Society of Hematology
• Peer Reviewed: Peer Reviewed
• Volume: 136
• Issue: 9
• Pages: 1055-1066
• DOI: https://doi.org/10.1182/blood.2020005844
• Public URL: https://durham-repository.worktribe.com/output/1292714