Determination of Reference Values of Hematopoetic CELLS in Normal BONE Marrow By 10 Colors FLOW Cytometry in Brazilian Population

Purpose: To determine relative and absolute reference values of normality in individuals with no hematologic disease bone marrow, as well as normal patterns of maturation for the different hematopoietic lineages.

Methods: Bone marrow samples were collected from 46 healthy patients (16 women and 30 men) undergoing orthopedic surgery and were aged between 18 and 87 years (median 36 years). The analysis of 8 tubes performed in an equipment with 10 colors configuration enabled to evaluate and quantify (% and mm³) B lymphocytes (immature and mature), T lymphocytes (helper, cytotoxic, double negative, double positive), natural killer cells, granulocytes (myeloblasts, promyelocytes, myelocytes, metamyelocytes, rods and neutrophils), monocytes (monoblasts, promonocytes, mature monocytes, classical, intermediate and non-classical), erythroblasts (immature and mature), plasma cells, basophils, mast cells, myeloid dendritic cells and plasmacytoid dendritic cells. The results were evaluated according to sex (female and male), age group (<40, 40 to 60, >60 years), and described as median percentage and absolute values.

Results: In evaluating the results according to age group, we identified that older individuals presented an increase in plasma cells that expressed CD56 (p=0.031 in absolute values). In addition, they also had increase relation of CD4/CD8 ratio (p=0.002), mast cells (p=0.004 in percentages), non-classical monocytes (p=0.016 in percentages), as well as a decrease in cytotoxic T lymphocytes (p=0.031 in absolute values), double negative T lymphocytes (p=0.018 in absolute values), and natural killer cells that express CD56 (p =0.002 in absolute values and p=0.012 in percentages). Moreover, these individuals also presented higher natural killer cells that expressed CD56 and CD16 (p=0.024 in absolute values), myeloblasts (p=0.048 in absolute values), metamyelocytes/Rods (p=0.038 in absolute values), neutrophils (p=0.006 in absolute values), monoblasts (p=0.030 in absolute values), mature monocytes (p=0.024 in absolute values), classical monocytes (p=0.017), plasmacytoid dendritic cells (p=0.027 in absolute values), and mature erythroblasts (p=0.004 in absolute values). In the evaluation of the results according to sex, we identified that the population of mature B lymphocytes (p=0.013) and B lymphocytes that expressed CD5 (p=0.014) was higher in women, while the percentage of natural killer cells was relatively higher than in men (p=0.007), particularly in the population of cells that expressed CD56 and CD16 (p=0.013).

Conclusion: This study established reference values (absolute and relative) of B lymphocytes (immature and mature), T lymphocytes (helper, cytotoxic, double negative, double positive), natural killer cells, granulocytes (myeloblasts, promyelocytes, myelocytes, metamyelocytes, rods and neutrophils), monocytes (monoblasts, promonocytes, mature monocytes, classical, intermediate and non-classical), erythroblasts (immature and mature), plasma cells, basophils, mast cells, myeloid dendritic cells and plasmacytoid dendritic cells according sex and age group in bone marrow samples from individuals with no hematologic disease Maturational stages of B lymphocytes, granulocytes, monocytes and erythroblasts was shown to be stable regardless of sex and age.