Abstract
Individuals with low socioeconomic status (SES) are at greater risk of
contracting and developing severe disease compared to people with higher
SES. Age, sex, host genetics, smoking, and Cytomegalovirus (CMV)
serostatus are known to have a major impact on human immune responses
and thus susceptibility to infection. However, the impact of SES on
immune variability is not well understood or explored. Here, we used
data from the Milieu Intérieur project, a study of 1,000 healthy
volunteers with extensive demographic and biological data, to examine
the effect of SES on immune variability. We developed an Elo-rating
system using socioeconomic features such as education, income, and
household to objectively rank SES in the 1,000 donors. We observed sex
specific SES associations, such as females with a low SES having
significantly higher frequency of CMV seropositivity compared to high
SES females, and males from a low SES having significantly higher
frequency of active smoking compared to high SES males. Using random
forest models, we identified specific immune genes which were
significantly associated with SES in both baseline and immune challenge
conditions. Interestingly, many of the SES associations were sex-stimuli
specific, highlighting the complexity of these interactions. Our study
provides a new way of computing SES in human populations that can help
identify novel SES associations and reinforces biological evidence for
SES-dependent susceptibility to infection. This should serve as a basis
for further understanding the molecular mechanisms behind socioeconomic
status effects on immune responses and ultimately disease.