RESUMO
Infection of T cells by Epstein-Barr virus (EBV) causes chronic active EBV infection (CAEBV) characterized by T cell lymphoproliferative disorders (T-LPD) of unclear etiology. Here, we identified two homozygous biallelic loss-of-function mutations in PIK3CD and TNFRSF9 in a patient who developed a fatal CAEBV. The mutation in TNFRSF9 gene coding CD137/4-1BB, a costimulatory molecule expressed by antigen-specific activated T cells, resulted in a complete loss of CD137 expression and impaired T cell expansion toward CD137 ligand-expressing cells. Isolated as observed in one sibling, CD137 deficiency resulted in persistent EBV-infected T cells but without clinical manifestations. The mutation in PIK3CD gene that encodes the catalytic subunit p110δ of the PI3K significantly reduced its kinase activity. Deficient T cells for PIK3CD exhibited reduced AKT signaling, while calcium flux, RAS-MAPK activation, and proliferation were increased, suggestive of an imbalance between the PLCγ1 and PI3K pathways. These skewed signals in T cells may sustain accumulation of EBV-infected T cells, a process controlled by the CD137-CD137L pathway, highlighting its critical role in immunity to EBV.
Assuntos
Classe I de Fosfatidilinositol 3-Quinases/deficiência , Infecções por Vírus Epstein-Barr/etiologia , Herpesvirus Humano 4/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/deficiência , Ativação Viral/genética , Ativação Viral/imunologia , Classe I de Fosfatidilinositol 3-Quinases/química , Suscetibilidade a Doenças , Infecções por Vírus Epstein-Barr/diagnóstico , Mutação em Linhagem Germinativa , Histocitoquímica , Homozigoto , Humanos , Imunofenotipagem , Mutação com Perda de Função , Ativação Linfocitária , Transtornos Linfoproliferativos/diagnóstico , Transtornos Linfoproliferativos/etiologia , Transtornos Linfoproliferativos/metabolismo , Modelos Moleculares , Linhagem , Fosfolipase C gama/metabolismo , Conformação Proteica , Proteínas Proto-Oncogênicas c-akt , Proteínas Quinases S6 Ribossômicas/metabolismo , Análise de Sequência de DNA , Transdução de Sinais , Relação Estrutura-Atividade , Linfócitos T/virologia , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/químicaRESUMO
The interplay between immune recovery, cytomegalovirus (CMV)-reactivation, CMV-driven immunity and graft-versus-leukaemia effect (GVL) was analysed in 108 children (median age: 8 years) who underwent haematopoietic-stem cell transplantation (HSCT) for acute leukaemia. Follow-up was 2 years unless death or relapse occurred. CMV-polymerase chain reaction (PCR) was programmed weekly until month +3 post-HSCT. Immunomonitoring consisted of sequential lymphocyte subset enumerations and analyses of T-cell proliferative and γ-interferon responses to CMV and to adenovirus. In the 108 recipients, the 2-year relapse rate (RR) was 25% (median time to onset 4·5 months; range: 24 d-17 months). CMV reactivation occurrence was 31% (median time to onset 26 d). Donor/recipient CMV serostatus did not influence RR. Among the 89 recipients disease-free after day +120, i) early CMV-reactivation before day +30 was more frequent (P = 0·01) in the relapse recipient group opposed to the non-relapse group. ii) CD8(+) /CD28(-) and CD4(+) CD45RA(-) T-cell expansions induced by CMV did not influence RR, iii) Recovery of anti-CMV and also anti-adenovirus immunity and of naïve CD4(+) T-cells was faster in the non-relapse group (P = 0·008; 0·009 and 0·002 respectively). In contrast to adult acute myeloid leukaemia, CMV reactivation was associated with increased RR in this paediatric series. Accelerated overall immune recovery rather than CMV-driven immunity had a favourable impact on RR.
Assuntos
Infecções por Citomegalovirus/imunologia , Citomegalovirus/fisiologia , Efeito Enxerto vs Leucemia/imunologia , Leucemia/imunologia , Adolescente , Criança , Pré-Escolar , Citomegalovirus/isolamento & purificação , Infecções por Citomegalovirus/complicações , Feminino , Transplante de Células-Tronco Hematopoéticas , Humanos , Imunidade Celular , Lactente , Recém-Nascido , Leucemia/complicações , Leucemia/terapia , Masculino , Recidiva , Estudos Retrospectivos , Fatores de Risco , Subpopulações de Linfócitos T/imunologia , Resultado do Tratamento , Viremia/complicações , Viremia/imunologia , Ativação ViralRESUMO
Age-related changes in memory CD4 T cells (CD4) are poorly known. To address this issue, CD4 proliferative and cytokine responses to an anti-CD3 monoclonal (CD3), to cytomegalovirus (CMV), and to adenovirus (AdV) were assessed in 57 children (age, 0.07-17.16 y) and 17 adults. Results showed i) accumulation of memory CD4 with aging, with 2-3 times more central-memory T cell (TCM; CD45RA/CD62L) than effector-memory T cell (TEM; CD45RA/62L) CD4 at any age. ii) In children older than 2 y, CMV-specific CD4-secreting IFNγ alone predominated over CD4-secreting IL2 + IFNγ and a continuous increase, with aging, in IFNγ responses to the virus was observed. In contrast, in AdV infection, CD4-secreting IL2 + IFNγ predominated and IFNγ responses to the virus reached adult levels from 3 y of age. iii) In children aged 0-2 y, lower total IFNγ responses to CMV (p < 0.02), AdV (p = 0.05), and CD3 (p < 0.01) and lower IFNγ + IL2-responses (p = 0.1, p < 0.02, p < 0.05, respectively) contrasted with no decrease in CD4-secreting IFNγ alone. Defective proliferative responses to AdV (p = 0.03) were also observed. In conclusion, the development of memory CD4 differed in acute AdV and persistent CMV infections. Young age seemed to depress mostly polyfunctional (IL2 + IFNγ secreting) CD4 in both infections.
Assuntos
Adenoviridae/imunologia , Envelhecimento/imunologia , Linfócitos T CD4-Positivos/imunologia , Citomegalovirus/imunologia , Memória Imunológica , Adolescente , Adulto , Fatores Etários , Anticorpos Monoclonais , Complexo CD3/imunologia , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/virologia , Proliferação de Células , Criança , Pré-Escolar , França , Humanos , Lactente , Recém-Nascido , Interferon gama/metabolismo , Interleucina-2/metabolismo , Selectina L/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Ativação LinfocitáriaRESUMO
The nature of adenovirus (AdV)-specific T cells that could best predict the capacity of immunocompromised host to fight AdV is unclear. To this aim, 47 pediatric patients were enrolled for at least 3 months either at allogeneic bone marrow transplantation (BMT) (23 genoidentical, 18 unrelated of which 9 were 10/10 and 9 were 9/10 HLA-matched) or at unrelated cord blood transplantation (n = 6). Enumeration of AdV-specific CD4 T cells secreting cytokines (flow cytometry) and proliferative responses to AdV ((3)HT-incorporation) were compared to AdV-DNAemia. A total of 44/47 patients did not evidence AdV-DNAemia. Thirty-two of 44 (73%) developed CD4-mediated interferon-gamma (IFN-γ) responses to AdV (median 0.36 CD4/µL of blood) since the first month post-HSCT (n = 11: 8 genoidentical and 3 unrelated) or the third month (n = 21 additional patients). At 3 months, both incidence and level intensities of AdV-specific CD4 appeared similar in genoidentical and unrelated BMT (70% and 80%; 0.36 and 0.21 CD4/µL, respectively) and not statistically different from age-matched controls (76%; 1.35 CD4/µL), whereas cord blood transplanted patients exhibited similar incidence but higher level intensities (67%; 1.49 CD4/µL). Polyfunctional (IL2 + IFN-γ) and proliferative responses appeared later, after the third month. Three of 4 9/10 HLA-matched unrelated HSCT that did not develop immunity to AdV presented chemotherapy-resistant AdV-DNAemia at 3 to 5 months post-hematopoietic stem cell transplantation (HSCT). Two were successfully treated with AdV-specific CTL infusion. Monitoring, since month 1 post-HSCT, of IFN-γ-secreting AdV-specific CD4 appears suitable for early detection of at-risk patients especially in 9/10 HLA-matched unrelated HSCT and preferable to monitoring of more delayed IL2- and proliferative responses.