OK, here is a short summary of the key points for those of us who arent at our best at the moment: Researchers from Spain who usually look at the immune systems of HIV patients took a look at a group of ME/CFS patients. They looked at the different types of white blood cells in our blood and compared what they found with a group of healthy controls. They found that some types of white blood cell counts were higher than they should be, while some others were lower the normal. Additionally, they found that some of these cells didn't respond as they normally would. Overall this suggests that we have some immune impairment, which may explain why we get co-infections like herpes, etc. Some of these findings were very similar to previous findings in ME/CFS by researchers in Australia. These immune cell differences were strong and consisitant enough that if you put an ME/CFS patient's results next to a healthy person's results, you could identify which was the ME/CFS patient. So, it could be possible to diagnose ME/CFS with these markers - we'd have a blood test for ME/CFS. But it is an early stage in the research, so it has real promise, but we need more checks yet before we know this would work in the general ME/CFS population.