Search

Antigen-specific multifunctional T cells that secrete interferon-γ, interleukin-2 and tumour necrosis factor-α simultaneously after activation are important for the control of many infections. It is unclear if these CD8(+) T cells are at an early or late stage of differentiation and whether telomere erosion restricts their replicative capacity. We developed a multi-parameter flow cytometric method for investigating the relationship between differentiation (CD45RA and CD27 surface phenotype), function (cytokine production) and replicative capacity (telomere length) in individual cytomegalovirus (CMV) antigen-specific CD8(+) T cells. This involves surface and intracellular cell staining coupled to fluorescence in situ hybridization to detect telomeres (flow-FISH). The end-stage/senescent CD8(+) CD45RA(+) CD27(-) T-cell subset increases significantly during ageing and this is exaggerated in CMV immune-responsive subjects. However, these end-stage cells do not have the shortest telomeres, implicating additional non-telomere-related mechanisms in inducing their senescence. The telomere lengths in total and CMV (NLV)-specific CD8(+) T cells in all four subsets defined by CD45RA and CD27 expression were significantly shorter in old compared with young individuals in both a Caucasian and an Asian cohort. Following stimulation by anti-CD3 or NLV peptide, similar proportions of triple-cytokine-producing cells are found in CD8(+) T cells at all stages of differentiation in both age groups. Furthermore, these multi-functional cells had intermediate telomere lengths compared with cells producing only one or two cytokines after activation. Therefore, global and CMV (NLV)-specific CD8(+) T cells that secrete interferon-γ, interleukin-2 and tumour necrosis factor-α are at an intermediate stage of differentiation and are not restricted by excessive telomere erosion.

Cytomegalovirus; Immuno-guided prophylaxis; Lung transplantation Citomegalovirus; Profilaxis inmunoguiada; Trasplante de pulmón Citomegalovirus; Profilaxi immuno-guiada; Trasplantament de pulmó INTRODUCTION: Prolonged use of antivirals to prevent the development of cytomegalovirus (CMV) disease in lung transplant patients has been shown to have significant side effects, for which alternatives are being sought to reduce their use. The monitoring of cell immunity against CMV could be an alternative as it has shown to be useful in identifying transplant patients at low risk of infection, who could benefit from shorter prophylaxis. The aim of the CYTOCOR study is to demonstrate that the combination of a reduced prophylaxis strategy with subsequent CMV-specific immunological monitoring would allow CMV infection to be controlled in lung transplant patients as effectively as the usual strategy (prophylaxis followed by pre-emptive therapy), while reducing the side effects of antivirals due to the shorter duration of prophylaxis. METHODS AND ANALYSIS: Phase III randomised, open, multicentre, parallel, non-inferiority clinical trial to study the efficacy and safety of the combination of a prophylaxis strategy up to month +3 post-transplant followed by immuno-guided prophylaxis using the QuantiFERON-CMV technique up to month +12 post-transplant to prevent CMV disease in CMV-seropositive lung transplant recipients. This strategy will be compared with a combination of a usual prophylaxis strategy up to month +6 post-transplant followed by pre-emptive therapy up to month +12. To study the incidence of CMV disease, patients will be followed up to 18 months post-transplantation. A total of 150 patients are expected to be recruited for the study. ETHICS AND PUBLIC DISSEMINATION: The clinical trial has been approved by the Research Ethics Committees and authorised by the Spanish Agency of Medicines and Medical Devices (AEMPS).If the hypothesis of this clinical trial is verified, the dissemination of the results could change clinical practice by increasing knowledge about the safety and efficacy of discontinuing valganciclovir prophylaxis in lung transplant recipients. We would like to acknowledge the support of the Spanish Network for Research in Infectious Disease (REIPI, RD16/0016), the Group for the Study of Infections in Transplant Recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and SCReN (Spanish Clinical Research Network) funded by the ISCIII-Sub-Directorate General for Research Assessment and Promotion through project PT13/0002/0010-PT17/0017/0012 and PT17/0017/0032.