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Lundgren S, Myllymäki M, Järvinen T, Keränen MAI, Theodoropoulos J, Smolander J, Kim D, Salmenniemi U, Walldin G, Savola P, Kelkka T, Rajala H, Hellström-Lindberg E, Itälä-Remes M, Kankainen M, Mustjoki S. Somatic mutations associate with clonal expansion of CD8 + T cells. SCIENCE ADVANCES 2024; 10:eadj0787. [PMID: 38848368 PMCID: PMC11160466 DOI: 10.1126/sciadv.adj0787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 05/06/2024] [Indexed: 06/09/2024]
Abstract
Somatic mutations in T cells can cause cancer but also have implications for immunological diseases and cell therapies. The mutation spectrum in nonmalignant T cells is unclear. Here, we examined somatic mutations in CD4+ and CD8+ T cells from 90 patients with hematological and immunological disorders and used T cell receptor (TCR) and single-cell sequencing to link mutations with T cell expansions and phenotypes. CD8+ cells had a higher mutation burden than CD4+ cells. Notably, the biggest variant allele frequency (VAF) of non-synonymous variants was higher than synonymous variants in CD8+ T cells, indicating non-random occurrence. The non-synonymous VAF in CD8+ T cells strongly correlated with the TCR frequency, but not age. We identified mutations in pathways essential for T cell function and often affected lymphoid neoplasia. Single-cell sequencing revealed cytotoxic TEMRA phenotypes of mutated T cells. Our findings suggest that somatic mutations contribute to CD8+ T cell expansions without malignant transformation.
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Affiliation(s)
- Sofie Lundgren
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
| | - Mikko Myllymäki
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
| | - Timo Järvinen
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Mikko A. I. Keränen
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
- Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
| | - Jason Theodoropoulos
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
| | - Johannes Smolander
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
| | - Daehong Kim
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
| | - Urpu Salmenniemi
- Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Stem Cell Transplantation Unit, Turku University Hospital, Turku, Finland
| | - Gunilla Walldin
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden
| | - Paula Savola
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
- Department of Clinical Chemistry, HUS Diagnostic Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Tiina Kelkka
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
| | - Hanna Rajala
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
- Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
| | - Eva Hellström-Lindberg
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden
| | - Maija Itälä-Remes
- Stem Cell Transplantation Unit, Turku University Hospital, Turku, Finland
| | - Matti Kankainen
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Satu Mustjoki
- Hematology Research Unit Helsinki, University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland
- Translational Immunology Research Program and Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland
- ICAN Digital Precision Cancer Medicine Flagship, Helsinki, Finland
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Järvinen E, Suomi F, Stewart JB, Guala D, Valori M, Jansson L, Nieminen J, McWilliams TG, Tienari PJ. Cultured lymphocytes' mitochondrial genome integrity is not altered by cladribine. Clin Exp Immunol 2023; 214:304-313. [PMID: 37860849 PMCID: PMC10719213 DOI: 10.1093/cei/uxad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/29/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023] Open
Abstract
Cladribine tablets are a treatment for multiple sclerosis with effects on lymphocytes, yet its mode of action has not been fully established. Here, we analyzed the effects of cladribine on mitochondrial DNA integrity in lymphocytes. We treated cultured human T-cell lines (CCRF-CEM and Jurkat) with varying concentrations of cladribine to mimic the slow cell depletion observed in treated patients. The CCRF-CEM was more susceptible to cladribine than Jurkat cells. In both cells, mitochondrial protein synthesis, mitochondrial DNA copy number, and mitochondrial cytochrome-c oxidase-I mRNA mutagenesis was not affected by cladribine, while caspase-3 cleavage was detected in Jurkat cells at 100 nM concentration. Cladribine treatment at concentrations up to 10 nM in CCRF-CEM and 100 nM in Jurkat cells did not induce significant increase in mitochondrial DNA mutations. Peripheral blood mononuclear cells from eight multiple sclerosis patients and four controls were cultured with or without an effective dose of cladribine (5 nM). However, we did not find any differences in mitochondrial DNA somatic mutations in lymphocyte subpopulations (CD4+, CD8+, and CD19+) between treated versus nontreated cells. The overall mutation rate was similar in patients and controls. When different lymphocyte subpopulations were compared, greater mitochondrial DNA mutation levels were detected in CD8+ (P = 0.014) and CD4+ (P = 0.038) as compared to CD19+ cells, these differences were independent of cladribine treatment. We conclude that T cells have more detectable mitochondrial DNA mutations than B cells, and cladribine has no detectable mutagenic effect on lymphocyte mitochondrial genome nor does it impair mitochondrial function in human T-cell lines.
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Affiliation(s)
- Elina Järvinen
- Merck OY, Espoo, Finland (an affiliate of Merck KGaA, Darmstadt, Germany)
| | - Fumi Suomi
- Translational Stem Cell Biology and Metabolism Program, Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - James B Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences Newcastle University, Newcastle Upon Tyne, UK
| | - Dimitri Guala
- Merck AB, Solna, Sweden (an affiliate of Merck KGaA, Darmstadt, Germany)
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Miko Valori
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Lilja Jansson
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, Neurocenter, Helsinki, Finland
| | - Janne Nieminen
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, Neurocenter, Helsinki, Finland
| | - Thomas G McWilliams
- Translational Stem Cell Biology and Metabolism Program, Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pentti J Tienari
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, Neurocenter, Helsinki, Finland
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Lehikoinen J, Valori M, Jääskeläinen AJ, Laakso SM, Arstila TP, Tienari PJ. High Epstein-Barr virus capsid antigen IgG level associates with the carriership of CD8+ T cell somatic mutations in the STAT3 SH2 domain. Clin Immunol 2023; 255:109733. [PMID: 37572949 DOI: 10.1016/j.clim.2023.109733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/14/2023]
Abstract
High carrier prevalence of STAT3 SH2 domain somatic mutations was recently discovered in CD8+ T cells. We found these low-allele-fraction clones in 26% of donors, without difference between multiple sclerosis (MS) patients and controls. Here we tested whether anti-viral antibodies associate with the carriership of these mutant clones. We compared antibody responses against common viruses in mutation carriers vs. non-carriers. Plasma samples of 152 donors (92 MS patients, 60 controls) were analyzed for antibodies against cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus-6A and parvovirus B19. The mutation carrier status associated with EBV VCA IgG level (p = 0.005) and remained significant after logistic regression (p = 0.036). This association was contributed similarly by MS patients and controls. These results suggest that EBV contributes to the generation or growth of these clones. The pathogenic role of the STAT3 mutant clones in MS is presently unclear, but their detailed characterization warrants further study.
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Affiliation(s)
- Joonas Lehikoinen
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Brain Center, Helsinki University Hospital, Helsinki, Finland.
| | - Miko Valori
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Anne J Jääskeläinen
- HUS Diagnostic Center, Clinical Microbiology, University of Helsinki and Helsinki University Hospital
| | - Sini M Laakso
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Brain Center, Helsinki University Hospital, Helsinki, Finland
| | - T Petteri Arstila
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Bacteriology and Immunology, Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pentti J Tienari
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Brain Center, Helsinki University Hospital, Helsinki, Finland
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