I have framed about 98% of my basement (1300sqft)and did not use any
treated wood. I used ujntreated 2x4's throughout and ramset the 2x4 into
the floor about every 16 inchs and ramset the 2x4's into the the concrete
walls about every 16 inch apart on the horizontal and about 3 feet apart
on the vertical (basically I have a tic-tac-toe design in the framing with
two studs going horizontal in the back of the uprights). The walls will
also be secured into the rafters. I did put a vapor barrier and I will be
using the moisture resistant insulation.

My question is: Do I need to rip out all the 2x4 on the concrete floor and
replace them with treated wood?

Once the work is done I will use a dehumidifier in the summer. I live in
Chicago if that means anything.

Thanks!