Pre-transplant thymic function is associated with the risk of cytomegalovirus disease after solid organ transplantation

Use of Viral Load as a Surrogate Marker in Clinical Studies of Cytomegalovirus in Solid Organ Transplantation: A Systematic Review and Meta-analysis

Symptomatic cytomegalovirus (CMV) disease has been the standard endpoint for clinical trials in organ transplant recipients. Viral load may be a more relevant endpoint due to low frequency of disease. We performed a meta-analysis and systematic review of the literature. We found several lines of evidence to support the validity of viral load as an appropriate surrogate end-point, including the following: (1) viral loads in CMV disease are significantly greater than in asymptomatic viremia (odds ratio, 9.3 95% confidence interval, 4.6-19.3); (2) kinetics of viral replication are strongly associated with progression to disease; (3) pooled incidence of CMV viremia and disease is significantly lower during prophylaxis compared with the full patient follow-up period (viremia incidence: 3.2% vs 34.3%; P < .001) (disease incidence: 1.1% vs 13.0%; P < .001); (4) treatment of viremia prevented disease; and (5) viral load decline correlated with symptom resolution. Based on the analysis, we conclude that CMV load is an appropriate surrogate endpoint for CMV trials in organ transplant recipients.

Effect of homeostatic T-cell proliferation in the vaccine responsiveness against influenza in elderly people

Background

Seasonal influenza virus infection is a significant cause of morbimortality in the elderly. However, there is poor vaccine efficacy in this population due to immunosenescence. We aimed to explore several homeostatic parameters in the elderly that could impact influenza vaccine responsiveness.

Methods

Subjects (> 60 years old) who were vaccinated against influenza virus were included, and the vaccine response was measured by a haemagglutination inhibition (HAI) test. At baseline, peripheral CD4 and CD8 T-cells were phenotypically characterized. Thymic function and the levels of different inflammation-related biomarkers, including Lipopolysaccharide Binding Protein (LBP) and anti-cytomegalovirus (CMV) IgG antibodies, were also measured.

Results

Influenza vaccine non-responders showed a tendency of higher frequency of regulatory T-cells (Tregs) before vaccination than responders (1.49 [1.08–1.85] vs. 1.12 [0.94–1.63], respectively, p = 0.061), as well as higher expression of the proliferation marker Ki67 in Tregs and different CD4 and CD8 T-cell maturational subsets. The levels of inflammation-related biomarkers correlated with the frequencies of different proliferating T-cell subsets and with thymic function (e.g., thymic function with D-dimers, r = − 0.442, p = 0.001).

Conclusions

Age-related homeostatic dysregulation involving the proliferation of CD4 and CD8 T-cell subsets, including Tregs, was related to a limited responsiveness to influenza vaccination and a higher inflammatory status in a cohort of elderly people.

Electronic supplementary material

The online version of this article (10.1186/s12979-019-0154-y) contains supplementary material, which is available to authorized users.

Ongoing burden of disease and mortality from HIV/CMV coinfection in Africa in the antiretroviral therapy era

Human Cytomegalovirus (CMV) is a well-recognized pathogen in the context of HIV infection, but since the roll out of ART, clinical and scientific interest in the problem of HIV/CMV coinfection has diminished. However, CMV remains a significant cofactor in HIV disease, with an influence on HIV acquisition, disease progression, morbidity, and mortality. Disease manifestations may be a result of direct interplay between the two viruses, or may arise as a secondary consequence of immune dysregulation and systemic inflammation. The problem is most relevant when the rates of coinfection are high, most notably in sub-Saharan Africa, and in children at risk of acquiring both infections early in life. Understanding the interplay between these viruses and developing strategies to diagnose, treat and prevent CMV should be a priority.