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

Abstract

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 influences on the Epo-independent erythroid colony formation in PV.

Increase of CD34 positive cells in polycythaemia vera

“…The results of the present study have shown that the percentage as well as concentration of CD34' cells in peripheral blood are significantly higher in patients with PV than in healthy controls, a finding in accordance with a recent report by de Wolf et al (14). This observation is likely to indicate that patients with PV have a larger circulating pool of peripheral stem cells and/or progenitor cells than normal subjects.…”

“…The glycophosphoprotein CD34 is expressed on early haematopoietic stem cells and progenitor cells and can be quantitated with an immunological technique (13). Indeed, an increased number of CD34 antigen expressing (CD34+) cells in peripheral blood was observed in a few PV patients investigated (14).…”

Ruxolitinib in the treatment of polycythemia vera: patient selection and special considerations

“… 8 , 9 In the 1990s, this phenomenon was complemented by the discovery of increased reactivity to other cytokines, such as interleukin 1, interleukin 3, granulocyte macrophage colony-stimulating factor, and insulin-like growth factor 1. 35 , 36 …”