- Elevated serum tryptase levels identify a subset of patients with a myeloproliferative variant of idiopathic hypereosinophilic syndrome associated with tissue fibrosis, poor prognosis, and imatinib responsiveness. Klion, A.D., Noel, P., Akin, C., Law, M.A., Gilliland, D.G., Cools, J., Metcalfe, D.D., Nutman, T.B. Blood (2003)









