CD28null pro-atherogenic CD4 T-cells explain the link between CMV infection and an increased risk of cardiovascular death

An increased risk of cardiovascular death in Cytomegalovirus (CMV)-infected individuals remains unexplained, although it might partly result from the fact that CMV infection is closely associated with the accumulation of CD28 null T-cells, in particular CD28 null CD4 T-cells. These cells can directl...

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Published in:Theranostics 2018-08, Vol.8 (16), p.4509-4519
Main Authors: Pera, Alejandra, Caserta, Stefano, Albanese, Fabio, Blowers, Pinar, Morrow, George, Terrazzini, Nadia, Smith, Helen E, Rajkumar, Chakravarthi, Reus, Bernhard, Msonda, James R, Verboom, Murielle, Hallensleben, Michael, Blasczyk, Rainer, Davies, Kevin A, Kern, Florian
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Language:English
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Research Paper
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Summary:An increased risk of cardiovascular death in Cytomegalovirus (CMV)-infected individuals remains unexplained, although it might partly result from the fact that CMV infection is closely associated with the accumulation of CD28 null T-cells, in particular CD28 null CD4 T-cells. These cells can directly damage endothelium and precipitate cardiovascular events. However, the current paradigm holds that the accumulation of CD28 null T-cells is a normal consequence of aging, whereas the link between these T-cell populations and CMV infection is explained by the increased prevalence of this infection in older people. Resolving whether CMV infection or aging triggers CD28 null T-cell expansions is of critical importance because, unlike aging, CMV infection can be treated. Methods: We used multi-color flow-cytometry, antigen-specific activation assays, and HLA-typing to dissect the contributions of CMV infection and aging to the accumulation of CD28 null CD4 and CD8 T-cells in CMV+ and CMV- individuals aged 19 to 94 years. Linear/logistic regression was used to test the effect of sex, age, CMV infection, and HLA-type on CD28 null T-cell frequencies. Results: The median frequencies of CD28 null CD4 T-cells and CD28 null CD8 T-cells were >12-fold (p=0.000) but only approximately 2-fold higher (p=0.000), respectively, in CMV+ (n=136) compared with CMV- individuals (n=106). The effect of CMV infection on these T-cell subsets was confirmed by linear regression. Unexpectedly, aging contributed only marginally to an increase in CD28 null T-cell frequencies, and only in CMV+ individuals. Interestingly, the presence of HLA-DRB1*0301 led to an approximately 9-fold reduction of the risk of having CD28 null CD4 T-cell expansions (OR=0.108, p=0.003). Over 75% of CMV-reactive CD4 T-cells were CD28 null . Conclusion: CMV infection and HLA type are major risk factors for CD28 null CD4 T-cell-associated cardiovascular pathology. Increased numbers of CD28 null CD8 T-cells are also associated with CMV infection, but to a lesser extent. Aging, however, makes only a negligible contribution to the expansion of these T-cell subsets, and only in the presence of CMV infection. Our results open up new avenues for risk assessment, prevention, and treatment.
ISSN:1838-7640
DOI:10.7150/thno.27428