Lymphocyte cell counts in middle age are positively associated with subsequent all-cause and cardiovascular mortality
A C Phillips1, D Carroll, C R Gale
1School of Sport and Exercise Sciences, University of Birmingham, Birmingham B15 2TT, UK. a.c.phillips@bham.ac.uk
Insights
Higher T-cell counts, specifically CD8+ T-cells, increase risks for all-cause and cardiovascular mortality. Conversely, a higher CD4:CD8 ratio is protective, while elevated B-cells also predict cardiovascular mortality.
Area of Science:
- Immunology
- Epidemiology
- Cardiovascular Medicine
Background:
- Elevated white blood cell counts are linked to increased mortality.
- The prognostic value of specific lymphocyte subsets for mortality remains unclear.
Purpose of the Study:
- To investigate the association between T-cell, CD4+, CD8+, and B-cell counts, and the CD4:CD8 ratio with all-cause and cardiovascular disease (CVD) mortality.
Main Methods:
- Flow cytometry was used to measure lymphocyte subsets in 4256 male veterans.
- Mortality data, including cause of death, were collected over a 15-year follow-up period.
Main Results:
- High T-cell counts correlated with increased all-cause and CVD mortality.
- High CD8+ T-cell counts were linked to all-cause mortality, while high CD4+ T-cell counts were associated with CVD mortality.
- A high CD4:CD8 ratio demonstrated a protective effect against all-cause mortality, and elevated B-cell counts predicted CVD mortality.
Conclusions:
- Circulating lymphocyte and lymphocyte subset numbers possess significant prognostic value for both all-cause and CVD mortality.
- These findings highlight the potential of immune cell profiling in predicting mortality risk.
Background:
There is an association between higher white blood cell counts and all-cause and cardiovascular disease (CVD) mortality. However, little is known about the prognostic significance of circulating lymphocyte and lymphocyte subset numbers.
Aims:
The present study examined the association between T-, CD4-, CD8- and B-cell numbers, and the CD4:CD8 ratio, and all-cause and CVD mortality.
Methods:
Lymphocyte and lymphocyte subset numbers were measured by flow cytometry in a cohort of 4256 male middle-aged Vietnam-era US veterans. Mortality was tracked for 15 years and cause of death was determined from death certificates.
Results:
In fully adjusted survival analyses, high circulating T-cells numbers were associated with increased risk of both all-cause [hazard ratio (HR)=1.75, 95% confidence interval (CI) 1.15-2.66] and cardiovascular (HR=3.57, 95% CI 1.53-8.33) mortality. The former association appeared to reflect an effect for high CD8-cells numbers, the latter an effect for high CD4-cell numbers. For all-cause mortality, a high CD4:CD8 ratio was protective (HR=0.58, 95% CI 0.41-0.81). Cardiovascular mortality was also predicted by high B-cells numbers (HR=1.87, 95% CI 1.10-3.17).
Conclusion:
Circulating lymphocyte and lymphocyte subset numbers may have substantial prognostic significance for both all-cause and CVD mortality.
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