While others have touched on it, I think it's worth emphasizing that these (especially the first two) have pretty clearly been modified heavily after being taken.
Don't get me wrong: You can certainly do high-key lighting without doing post-processing. For example, this has essentially no post-processing at all:
Also note, however, that it doesn't look much like the pictures you posted. Most of the difference between something like this and the pictures you posted is going to happen primarily in Photoshop (or Gimp, etc.) Based on the amount of noise in the shadows of those shots, I'd guess the shaded parts of the face actually started out considerably darker than they are in this picture.
Just for example, however, I doubt that it's possible to get eyes that look like the pictures you posted (at least the first and last pictures) just with lighting. Eyes just don't look enough like that to get that effect with lighting -- you need to do heavy-duty post-processing to get them like that. Just for one example, the whites of real eyes aren't really that white, and while lighting can/will affect it to some degree, you can only get that by modifying the picture.
If I had to guess about the post-processing that was used, I'd say they de-saturated the green a lot (e.g., look at the green/grey stripes on the jacket), and the red somewhat less, but still quite a bit (e.g., the lips and red stripes on the jacket). Based on the washed out skin/hair, and considerably more saturated colors in the jacket, I'd guess they used the "vibrance" and "saturation" sliders in ACR (or something similar) with the "vibrance" set to something like -20 to de-saturate all the areas that started out with low saturation, then turned the "saturation" slider up quite a ways, to get a rather sudden transition to much more saturated after the original saturation exceeded a certain level (so the saturation of the skin, for one example, is reduced, but of the jacket is probably increased).