Interesting study. BIG twin study! Really high heritability - probably why autoimmune diseases are so heritable. Note though that innate immune problems - which seem to happen more in ME/CFS - are more effected by the environment - by the infections we get, etc.
Here we analyse 23,394 immune phenotypes in 497 adult female twins. 76% of these traits show a predominantly heritable influence, whereas 24% are mostly influenced by environment. These data highlight the importance of shared childhood environmental influences such as diet, infections or microbes in shaping immune homeostasis for monocytes, B1 cells, γδ T cells and NKT cells, whereas dendritic cells, B2 cells, CD4+ T and CD8+ T cells are more influenced by genetics. Although leukocyte subsets are influenced by genetics and environment, adaptive immune traits are more affected by genetics, whereas innate immune traits are more affected by environment.
it is possible that variation in innate or innate like cells (for example, NKT, MAIT and γδ T cells) is more influenced by exposure to infections, microbes and other immunological insults.
Examination of these trends reveals common threads. For example, the predilection towards a shared environmental influence of CD4 polarization markers (for example, Th1 versus Th2 polarization), NKT cells, Vδ1T cells and B1 cells is likely to be due to a shared exposure to microbial products during childhood/adolescence: either through microbiome or common infections. Many of these cell types bridge the span between the innate and the adaptive immune system12 and have been postulated to have functional roles in the immunity to common bacterial or parasitic infections.