Variation in the human immune system is largely driven by non-heritable influences.
Level 4 - case-series / case-control
Cross-sectional twin study evaluating heritability of immune traits
PubMed 25594173 · doi:10.1016/j.cell.2014.12.020
What was done
A systems-level immunological assessment was performed on 210 healthy twins aged 8 to 82 years to evaluate the relative contributions of heritable versus non-heritable factors. Researchers measured 204 distinct immune parameters, including cell population frequencies, cytokine responses, and serum proteins. The study also examined serological responses following seasonal influenza vaccination and compared monozygotic twin pairs discordant for cytomegalovirus infection.
What was found
Non-heritable influences accounted for more than 50% of the variance in 77% of the 204 measured immune parameters and more than 80% of the variance in 58% of them. Immune parameter variability increased with age. Serological responses to seasonal influenza vaccination were driven largely by non-heritable factors, and discordance for cytomegalovirus infection between monozygotic twins affected more than half of all measured parameters.
Why it matters
This study demonstrates that human immune variation is predominantly shaped by cumulative, non-heritable environmental exposures rather than genetic programming.
Limits
The total sample size is 210 individuals, and the abstract does not report the breakdown between monozygotic and dizygotic pairs. The cross-sectional design infers cumulative environmental impact across an age span rather than measuring longitudinal lifetime exposures directly.
Cited by
- supports A Stanford Medical School study co-authored by David Furman demonstrated that the majority of human immune system function is non-heritable and shaped by environmental influences.