The effects of IL‐1 and IL‐4 on the Epo‐independent erythroid progenitor in polycythaemia vera

摘要

Summary.Human recombinant interleukin‐1 (IL‐1) was studied for its effects on the erythroid progenitors from normal subjects and from patients with polycythaemia vera (PV). No supportive effect of IL‐1 was noticed on the normal erythropoietin (Epo) dependent, erythroid burst‐forming unit (BFU‐E) using peripheral blood or bone marrow. In contrast, the Epo‐independent BFU‐E from peripheral blood of PV patients could be stimulated significantly. This enhancing effect of IL‐1 was not only observed with unsorted but also with sorted CD34+cells. In addition, it was shown that IL‐1 indirectly stimulated the Epo‐independent BFU‐E because anti‐GM‐CSF could abrogate the supportive effects of IL‐1. In contrast to the Epo‐independent BFU‐E, the Epo‐dependent erythroid colony formation from PV patients could not be augmented by IL‐1. Finally, we studied the effects of IL‐4 on the Epo‐independent BFU‐E, because IL‐4 can affect the erythroid colony formation and modulate the effects of IL‐1. IL‐4 suppressed the Epo‐independent BFU‐E. This effect could be counteracted by the addition of IL‐1 to the culture medium. However, the suppressive effect of IL‐4 was not related to a decline in spontaneous release of IL‐1, because an anti‐IL‐1 antibody did not modify the spontaneous erythroid colony formation. These data indicate that IL‐1 and IL‐4 exert separate i