That's a very interesting theory. I had assumed that the immune-system hadn't been implicated in my case (all the immune-system bloodwork came back normal), but now you have me wondering just a bit, so thanks for sharing.
Your body goes to enormous lengths to normalize your blood because you rapidly die if your blood leaves a fairly narrow pH range. So it will strip your bones of calcium, leaving you with osteoporosis, to keep your blood as close to normal as possible.
I am skeptical about the value of blood tests. It seems to me that by the time a blood test shows a problem, things have to be pretty bad. I think reliance on blood tests probably misses a lot.
Edit: I was almost certainly barking up the wrong tree here: calcium levels have nothing to do with how much your joints pop. :-)
Hmm, well that part about calcium is quite interesting, at least in my case. I say this because right around the time I started getting leg cramps, my joints started popping like crazy.
My working hypothesis was always that the tight muscles were pulling on the joints, causing them to pop more easily. But maybe now I was actually being slightly deprived of calcium? I say slightly because the calcium blood levels were normal.