Mary Lou from the previous sequel The Rebirth has a brief, non-speaking cameo as a circus audience member in the beginning of the film. Although her quick appearance won't be referenced until the following sequel, New Moon Rising.
Despite the fact that this film states "Based on the novels 'The Howling I, II, and III' written by Gary Brandner", this film is in no way based on any of those novels, and is a sequel to the earlier Howling films in name only.
R.B Harker: I may not know your name... or your face, BOY! But I know you. I've been watching you. I know what you need. You're the worst kind of freak: one who tries to control it. But you can't! You can't deny your true nature.