Oh, please. The school life aspect is common in anime, no matter what. Ranks do exist in some vampire mythology, though usually this is separated by sire/sired etc.
Anyways, its nothing Japan hasn't perverted before, basically making them a mix between witches and goths, with a fetish for blood mixed in.
Having read and watched it, I have to say its really not too bad considering the pile of shitojo out there.