- The primary defect in experimental ileitis originates from a nonhematopoietic source. Olson, T.S., Reuter, B.K., Scott, K.G., Morris, M.A., Wang, X.M., Hancock, L.N., Burcin, T.L., Cohn, S.M., Ernst, P.B., Cominelli, F., Meddings, J.B., Ley, K., Pizarro, T.T. J. Exp. Med. (2006)