Most people don’t realize this, but Italics are actually an entirely different alphabet than the lowercase roman alphabet. Italic letters are constructed differently to resemble hand writing—they do not have to be slanted.
I repeat: Italic does not mean slanted. Slanting letters uniformly actually results in Obliques, or false Italics. Good typefaces have true Italics, mediocre ones have Obliques. Try to use the former. Here are examples: