More than genes, environment influences immune system

When it comes to the formation and shaping up of the immune system, environment plays a more significant role compared to one’s genetic makeup, says a new study. Immune system keeps modifying itself all through an individual’s life to fight disease, suggested Mark Davis, director of Stanford’s Institute for Immunity, Transplantation and Infection. He is the one who led this latest work.

It’s been long known that the way immune system functions in healthy individuals show great variations. To find out what could be the specific role of environment, in this study, scientists compared 78 pairs of identical twins with identical genetic make ups and 27 pairs of non-identical twins, who had about 50 percent of their genes in common, reports The New York Times.


The blood samples from the twin pairs were analyzed. Their age ranged from 8 to 82. More than 200 immune components were studied. The finding suggests that three-quarters of the immune system differences between the twins were due to the impacts from the environment such as previous exposure to microbes or toxins in the form of vaccinations and diet.

“Nonheritable influences, particularly microbes, seem to play a huge role in driving immune variation,” senior study author Mark Davis, a professor of microbiology and immunology and director of Stanford’s Institute for Immunity, Transplantation and Infection, said in a university news release.

Another interesting observation confirmed that the specific effects of the environment on the immune system were stronger amongst those who were 60 and older than those who were younger than 20. The same work came up with another intriguing finding.

Cytomegalovirus or CMV results in notorious outcome for people with weak immune systems but with healthy individuals, it proves to be quite harmless.

The Stanford group screened 16 pairs of identical twins, and only one of them had CMV the presence of CMV made substantial differences in around 60 percent of the components examined. The present study doesn’t offer any health advice, it just shows the influence of environmental factors in shaping up of the immune system, concluded Davis.

The work got published Jan. 15 in the journal Cell.