Complex immune responses are predominantly driven by genetics, according to a new British twins study published today.

The complex responses to attack and defeat pathogens like chickenpox or other germs is driven mostly by what is in our DNA – while the innate, constantly-on-guard immune responses are driven by environment, concludes the paper, published today in Nature Communications.

“Our results surprisingly showed how most immune response are genetic, very personalized and finely-tuned,” said Tim Spector, director of the TwinsUK Registry at King’s College London. “What this means is we are likely to respond in a very individualized way to an infection such as a virus – or an allergen such as a house dust mite causing asthma.”

The scientists looked at the genomes of 497 adult females who were twins. They focused in on nearly 23,000 immune phenotypes within those genetic sets, they said.

Some 76 percent of the complex immune responses were driven by genes, they found. These included dendritic cells, B2 cells, CD4+ T and CD8+ T cells.

However, the remaining 24 percent of the complex immune responses were influenced by environmental factors, which included shaping an immune homeostasis of monocytes, B1 cells, T cells, and NKT cells.

The findings were “unusual,” according to Massimo Mangino, the lead researcher, from King’s College London.

“Adaptive immune responses, which are far more complex in nature, appear to be more influenced by variations in the genome that we had previously thought,” Mangino said, in a statement released by the school. “In contrast, variation in innate responses (the simple non-specific immune response) more often arose from environmental differences. This discovery could have a significant impact in treating a number of autoimmune diseases.”

The twins’ immune systems show that heredity and early development determine major factors of life-long health.

However, the findings also provide the possibility of autoimmune responses, as the factors determining those conditions are increasingly isolated, they said.

“This may have big implications for future personalized therapy,” added Spector, director of the TwinsUK Registry.