Is there clinical, epidemiological and molecular evidence for two forms of Crohn's disease?

Crohn's disease is an idiopathic chronic panenteric intestinal inflammatory disease. Data concerning the pathogenesis of, and the immune responses occurring in, Crohn's disease are often conflicting. Current therapy is empirical and either non-specifically immunosuppressive or surgically ablative in nature. Although controversial, Crohn's disease may be thought of as having two different presentations, an aggressive fistulizing form and an indolent obstructive form. This is analogous to the tuberculoid and lepromatous manifestations of leprosy. If correct, this subclassification may provide key insights into the pathogenesis and differing host immune responses in Crohn's disease and also allow the development of more rational therapies.