[Bolding Mine] ________________________________________ Hopefully, my following thumbnail of the summary is correct: Some NK cells (TRAIL+ NK cells) produce the TRAIL cytokine. This cytokine apparently can regulate the immune response to viral infection by suppressing (killing) responding CD4+ T cells. This prolongs the immune reaction by restraining the number of CD4+ T cells, but, counterintuitively, this turns out to be a good thing. In the absence of TRAIL, either due to low NK cell numbers or low NK cell activity, CD4+ T cell numbers are not constrained and this can promote autoimmunity. The study was in mice. When TRAIL+ NK cells were eliminated prior to murine cytomegalovirus (MCMV) infection, the mice developed an autoimmune response in the salivary glands similar in appearance to Sjögren's Syndrome. ________________________________________ Media reports on the paper. Scientists prove link between viral infection and autoimmune disease https://medicalxpress.com/news/2014-10-scientists-link-viral-infection-autoimmune.html Link between viral infection and autoimmune disease http://www.labonline.com.au/content...l-infection-and-autoimmune-disease-1124013397 My ME/CFS related speculation: Given the many findings of low NK cell activity in ME/CFS patients over the years, it is tempting to speculate that this may not be an effect of ME/CFS, but rather a cause, i.e., a predisposition for low NK cell activity leading to an unrestrained response to infection that winds up triggering autoimmunity. Also, an unrestrained, rapid response to infection might explain why a subset of ME patients seem "immune" to the flu or other infections. The response is so overwhelming, that the infection never takes hold. The penalty is ME/CFS.