IL1B and myeloproliferative disorder: Thirdly, the cytokine production of human megakaryocytic UT-7 cells was minimally affected by the expression of MPN main mutations: CALR exon 9 mutants had no effect at all, and JAK2V617F induced only three molecules: IL-1β and IP-10 (both correlated with the %JAK2V617F of patients) and RANTES.