We don't yet have a generally accepted 'model' of this disease. What's agreed is that it's the end stage of a long process. There are two leading hypotheses: 1) T3D (resistance in the astrocytes) and, 2) the one you mention, inflammation- which could be from infection or some other reason).

I tend towards T3D, but there's no reason it can't be both (either synergistically or separate processes with the same end result).

To which, I'd add 3) fat transport issues in the blood/brain barrier associated with APOE type 4

If you have familial AD, I'd strongly suggest sending some spit off to 23&me, using that to find out if you are APOE-4. No need to spend the $$$ for the medical analysis, you can get one for cheap at foundmyfitness.com or almost-free at promethase.com (the FmF results are much, much easier to understand - get that one if you're not a bio nerd)

If it turns out you have an APOE-4 allele, there's plenty you can do to head things off. Check out online resources like APoe4.info and FoundMyFitness.com.