How can one with pmr get a sed rate of >100 but one with lupus & organ involvement have a sed rate not nearly as high?

Good question: Sed rate is positive after a value of 30. The higher it is does not necessarily mean the greater the inflammation. Both these conditions create high sed rates. It's not so important what that means after it becomes positive. The part that is important is the "it's positive" part.

IL-6: Pmr & a related disease giant cell arteritis seem to share 1 quality: higher levels of a cytokine (immune protein) called interleukin-6. Why this is remains unclear, but il-6 drives the production of acute phase reactants which increase esr. Other autoimmune diseases appear to rely less on il-6 and more on other cytokines (tnf-a in ra) for inflammation.