Complex sentence: The reported association of XMRV and CFS, published in "Science", generated worldwide media coverage and subsequent conflicting study results, including numerous studies which were unable to detect XMRV in their CFS patient groups or their control populations, using blood samples or cerebrospinal fluid.
Split into simpler sentences: The reported association of XMRV and CFS, published in "Science", generated worldwide media coverage and subsequent conflicting study results. Independent laboratories have not detected XMRV in CFS patient groups or control populations, using blood samples or cerebrospinal fluid.