I emailed a few questions to Richard Easingwood, one of the New Zealand coauthors of a 1994 study that identified retroviral particles from the peripheral blood lymphocytes of ten of 34 CFS patients and none of the controls. Back then, the scientists reported that the majority of viral particles were similar to lentivirus and and murine leukemia virus. Now a senior electron microscopy technician at the University of Otago, Easingwood wrote back:
"That [study] was a long time ago! I have not revisited this research since then. My role in that study was fairly limited—I performed the electron microscopy and that was about it. To comment intelligently on it I would need to review the images (which I still have in storage) and possibly prepare more sections from the specimen blocks (which I still have) in the light of my electron microscopy experience now. I have 15 years+ extra experience since that paper was published and may look at the data differently. If I did this and reviewed the current literature I would be better able to form an opinion about this research. However, I will attempt to answer your questions as best I can.
They may have been virus particles. The structures we found were intriguing but it is possible that they were normal structures or artefactual.
I had no opinion on that back then.
Are the blood samples from those patients still frozen somewhere—or have they been discarded?
I don't know what happened to any of the samples other than those that I prepared for TEM [transmission electron microscopy], which I still have. If there were frozen samples I don't know their fate. However, the resin-embedded cells I have are stable indefinitely.
I would be very happy to review the existing old negatives (most of which haven't been published) and the stored resin-embedded samples. I suspect some kind of ethical approval may be required, I would have to check this.