As I understood it, there is a cascade of problems in the body in ME: inflammation, lack of oxygen in tissues (hypoxia), metabolic changes, dysbiose in the gut, sometimes autoimmunity, etc etc. Lyme can be the trigger that started that cascade. There are also other triggers, like Q-fever, EBV and other infections. I think post-lyme disease is the same as ME. I don't know if there is actually such a thing as chronic lyme disease, where there is still active Borellia after a lot of antibiotics. I think a lot of people are in that grey area. Some people have an obvious active lyme problem, there is no doubt to give them antibiotics. Some people are pretty obvious to have no lyme, no reaction on LTT or other tests. But there is a big group where it is less clear and you don't want to give everyone in that group long term antibiotics, but you don't want to risk giving no antibiotics to people who would really benefit from it. I had a very mild reaction to the LTT (2,2,0) and I only got treatment for the gut, but it does say on my papers that it is post-lyme.