The Role of Regulatory B Cells in Patients with Acute Myeloid Leukemia

BACKGROUND Regulatory B (Breg) cells are a group of B cells with immunomodulatory function, which mainly exert negative immunomodulatory function by secreting IL-10 and other cytokines. Due to their immunoregulatory properties, Breg cells may participate in the pathogenesis of acute myeloid leukemia (AML). This study was designed to explore the frequency of Breg cells and the relationship between the Breg cells and clinical data in patients with AML. MATERIAL AND METHODS A total of 46 (36 in peripheral blood, 10 in bone marrow) AML patients and 15 healthy donors (HD) were included for detection of Breg cells frequency by multicolor flow cytometry. All cases were divided into different groups according to FAB subtypes of leukemia, white blood cell count (WBC) levels, age, cytogenetic characteristics, and molecular abnormalities, and were compared the differences of Breg cell frequency. Survival curve analysis was performed to estimate the value of Breg cell frequency in prognosis among cases with AML. RESULTS We found that the frequency of Breg cells was higher in AML patients both in peripheral blood (PB) and in bone marrow (BM) compared with those in HDs. The AML patients with high WBC levels had higher Breg cell frequency compared with those with low WBC levels. Low-risk patients with had lower Breg cells frequency compared to the medium-risk patients. The patients with high WBC and high Breg cells frequency showed a shorter overall survival. Similarly, the overall survival of AML patients in the older group with high Breg cells frequency was significantly shorter than in the younger group with low Breg cell frequency. CONCLUSIONS For AML patients, the frequency of Breg cells was elevated, and high frequency of Breg cells may reveal poor prognosis.