Expression And Significance Of Immune Inhibitory Receptor LAIR-1 In Hematopoietic Stem/Progenitor Cells In Patients With Acute Myelogenous Leukemia

Objective:To investigate the expression of leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1,also called CD305) in hematopoietic stem/progenitor cells in patients with acute myelogenous leukemia (AML) 5 and to explore the correlation between LAIR-1 expression and AML; To establish the M07e AML cell line with stable and high expression of LAIR-1 for further study of the biological significance of LAIR-1 expression in AML cells.Methods: Flow cytometry was used to examine CD34 and LAIR-1 expression in bone marrow cells of 37 cases of AML patients and 10 cases of non-neoplastic patients were used as controls .Then analyze the relationship between LAIR-1 expression in CD34~+ cells and the peripheral white blood cell counts, hemoglobin,platelet counts, hepatosplenomegaly and lymphadenopathy. (2) The expression and position of LAIR-1 on M07e were identified by RT-PCR ,Western Blot and FCM .The LAIR-1 gene was transferred into the acute myeloid leukemia cell line M07e by Lentivirus vector to establish the LAIR-1-MO7e cell line with high and stable expression of LAIR-1.Results:(1) FCM results showed that the percentage of CD34~+ cells and mean indensity flourscence (MIF) of CD34 expression in bone marrow cells of AML patients was significantly higher than that in control group, and the LAIR-1 molecules were highly expressed in CD34~+ hematopoietic stem/progenitor cells. The MIF of LAIR-1 expression in CD34~+ cells of AML patients with lymphadenectasis(48.55±22.44 ) was significantly lower than that of AML patients without lymphadenectasis (84.43±45.78) (P<0.05). The CD34 and LAIR-1 expression levels of bone marrow cells had no statistically difference (P > 0.05) among different hemoglobin and platelet groups. (2 )The stable M07e cell lines with high expression of LAIR-1 molecules were successfully constructed.The high expression of LAIR-1 were confirmed by Real Time PCR, flow cytometry and LSCM.Conclusion: (1)The percentage of CD34~+ cells and the MIF of CD34 expression in bone marrow cells increased significantly in AML patients compared with controls, and CD34~+ cells express high level of LAIR-1.The expression level of LAIR-1 in AML patients with lymphadenectasis was significantly lower than that in AML patients without lymphadenectasis.These results indicate that LAIR-1 may play a role in AML. (2) The establishment of the LAIR-1-MO7e cell line may provide a useful tool for further stady the biological significance of LAIR-1 in AML.