But if another definition was used, say the Canadian ME/CFS definition, to be called ME/CFS for the rest of the E-mail. There would XMRV+ ME/CFS and XMRV- ME/CFS. Scientists could probably still find interesting things in the XMRV- ME/CFS group. But if a CFS (Reeves criteria) group is used, there would be: XMRV+ CFS (Reeves criteria) and XMRV- CFS (Reeves criteria). The second group is going to be an extra huge mess for scientists to study.