Probably not with any reasonable chance of success. At least in the U.S. legal system, if you can convince the jury that your allegation was in fact true, then that's an absolute defense to a defamation action. (There would also be other obstacles, which I won't address here.)
A necessary element for a defamation claim is that the statement be false. As this statement is 100% provably true, it is not defamation. They'd be thrown out in an instant.
I think I would side with that. Do you get sent to jail because someone saw you, or because you were stealing stuff?
You're sent to jail because you were caught, tried, and convicted of stealing things. The act of stealing alone does not send you to jail. Same with patent infringement. The act of infringement alone does not force Apple to shut down iMessage. VirnetX is required to actually file the lawsuit, and then win, for Apple to be required to shut it down.
[0] http://www.rcfp.org/first-amendment-handbook/introduction-de... (scroll down to "Falsity")