i just took the test yesterday, and i got quite a few immuno questions. a couple of them were certainly wtf but most of them i reasoned through pretty easily (i think). i used FA only and the basic concepts in there were what was stressed on step 1. qbank was good prep but their questions were much harder than the real thing. know your immuno diseases and t-cell/b-cell differentiation and activation pathways and you'll be fine. good luck!