ME/CVS is a serious chronic disease for which there is no proper treatment. In this project, blood from the ME/CVS biobank will be examined for the presence of so-called immune signatures, which indicate that the immune system is activated. It will also investigate whether immune cells in ME/CVS are hypersensitive to stimuli. This then leads to the formation of pathogenic inflammatory substances. If this is the case in ME/CVS, this research will show what makes ME/CVS patients sick and result in new treatment options.