Background
The myelodysplastic syndrome (MDS) is a high‐risk hemocytopenia easily converted to acute myeloid leukemia. CD47 plays an important role in regulating phagocytosis, and its role in the pathogenesis of MDS is unclear.
Methods
CD47 and PI3K/AKT/mTOR on CD34+CD38− cells were detected by flow cytometry. NF‐κB, PI3K, AKT, PTEN, and mTOR mRNA overexpressed in CD34+CD38−CD47+ cells were performed by real‐time quantitative transcriptase‐polymerase chain reaction. Phagocytic capacity of macrophages was measured with carboxyfluorescein succinimidyl ester and fluorescent microspheres. Sorted CD34+CD38−CD47+ cells were injected into NOD‐Prkdcscid Il2rgnull mice.
Results
The expression of CD47 on CD34+CD38− cells of the patients in high‐risk MDS based on IPSS‐R/WPSS score was higher than that in low‐risk MDS and controls. The signaling pathway of PI3K/AKT/mTOR is active in CD34+CD38−CD47+ cells of MDS patients. CD47 overexpressing CD34+CD38− cells has antiphagocytosis. CD47 overexpressing leukemia stem cell (LSC) ‐transplanted mice has a short survival time. The macrophages originated from MDS might elicit a pro‐tumor response in MDS by inhibiting phagocytosis.
Conclusions
Phagocytosis checkpoints are impaired in MDS. High expression of CD47 on CD34+CD38− cells indicates poor clinical prognosis in MDS.