The majority of the CD4+ CD28− cells were found to be HCMV-specific [148] and no autoreactivity could be measured in that particular study, although CD4+ CD28− T-cells in RA patients were found to be autoreactive in a previous study [156] and the CD4+ CD28− cells were only partially susceptible to the control by regulatory T-cells. Here, CD28 is linked to rheumatoid arthritis.