She is a little mad, then asks you if you will be this cruel to all the others. Several of her radio messages to Jack are different if you have harvested Little Sisters. For example, one line when Jack wakes up in her safe-house is: "You have committed many sins, but perhaps you can find some redemption." There is also a different message when Jack goes up to Fontaine's apartment: "So many innocents, and their blood is on your hands. I, too, know this shame. How will we ever account for our sins? But we must now set all of this aside. There is work to be done."
You can find all the variations of Tenenbaum's radio messages here: Radio Messages
You can also see the effect on Tenebaum's speech at the end of the game here.