Immunological studies in trans-individuals undergoing gender affirming hormone therapy

Personalized medicine for all requires a shift in science and clinical culture that puts more emphasis on the sources of inter-individual variation. Important examples are sex differences in the presentation and severity of diseases, as well as in responses to therapy. Understanding the mechanisms that drive these differences is important in the context of individualized healthcare, and also to better understand the immune sequelae of long-term sex hormone supplementation or inhibition in transgender individuals. Sex-specific differences in immunity are determined by genetics and by hormones. This Comment discusses first insights into the consequences of long-term sex-hormone supplementation on immunity in transgender individuals.