Contributions
Abstract: PB1856
Type: Publication Only
Background
Decrease of bone marrow (BM) B-cell precursors (BCP) is an important diagnostic feature in myelodysplastic syndromes (MDS). Moreover, their number is associated with patients’ overall survival. However, BCPs vary with age in normal BM.
Aims
In a multicenter study from the Brazilian Group of Flow Cytometry we analyzed the variation of BCPs in normal BM according to age, antibody combinations used for quantification and reproducibility after a centralized reanalysis. We set up a reference pattern of normal values for evaluation of patients with a suspected MDS.
Methods
In a retrospective study including 10 centers we retrieved analyses of BM donors and cases examined for elucidation of transitory reactive cytopenias presenting a normal BM immunophenotyping. BCPs were enumerated as CD19/CD34/CD45/CD10 cells (panel 1) or CD19/CD34/CD45 cells (panel 2), among the total nucleated cells and as percentage among CD34+ cells.
Results
134 cases were included. Panel 1 was applied in 106 cases (all centers) and panel 2 was used in 28 cases (3 centers). Age range: 10 months to 89 years. In the same age range, values for panel 2 were lower than those for panel 1. In a multiple regression, % BCP/total cells = -0.389 “log age” (years) – 0.313 (for panel 2) + correction factor for labs +1.873. The correction factor for labs was 0 to -0.40. Age explained alone 49.6% of the variance of % BCPs/total cells, while “laboratory” explained 5.2% and panel used explained only 0.8%. Age explained only 24.9% of the variance of BCPs/CD34+ cells.
| % total CD34+ cells | BCPs/total cells | BCPs/CD34+ cells | |
0-6 years (n=10) | 3.05% (1.5 - 5.1) | 2.8% (0.35-3.8) | 62.1% (22.8-62.6) |
7-18 years (n=19) | 1.43% (0.25 – 3.2) | 0.4% (0.02-1.8) | 41.5% (3.1-64.5) |
19-55 years (n=70) | 0.84 (0.07-2.76) | 0.13% (0.02-0.8) | 20.8% (2.6-60.4) |
>56 years (n=35) | 0.71% (0.06-2.48) | 0.08% (0.02-0.68) | 12.9% (1.3-55.2) |
Conclusion
in a normal population BM B-cell precursors varied mainly with age, but were also dependent on technical peculiarities of operators and equipments. Analysis by phenotype and as percentage of total cells was more accurate and less susceptible to variation.
Session topic: 23. Hematopoiesis, stem cells and microenvironment
Keyword(s): B cell subsets, flow cytometry, Bone Marrow
Abstract: PB1856
Type: Publication Only
Background
Decrease of bone marrow (BM) B-cell precursors (BCP) is an important diagnostic feature in myelodysplastic syndromes (MDS). Moreover, their number is associated with patients’ overall survival. However, BCPs vary with age in normal BM.
Aims
In a multicenter study from the Brazilian Group of Flow Cytometry we analyzed the variation of BCPs in normal BM according to age, antibody combinations used for quantification and reproducibility after a centralized reanalysis. We set up a reference pattern of normal values for evaluation of patients with a suspected MDS.
Methods
In a retrospective study including 10 centers we retrieved analyses of BM donors and cases examined for elucidation of transitory reactive cytopenias presenting a normal BM immunophenotyping. BCPs were enumerated as CD19/CD34/CD45/CD10 cells (panel 1) or CD19/CD34/CD45 cells (panel 2), among the total nucleated cells and as percentage among CD34+ cells.
Results
134 cases were included. Panel 1 was applied in 106 cases (all centers) and panel 2 was used in 28 cases (3 centers). Age range: 10 months to 89 years. In the same age range, values for panel 2 were lower than those for panel 1. In a multiple regression, % BCP/total cells = -0.389 “log age” (years) – 0.313 (for panel 2) + correction factor for labs +1.873. The correction factor for labs was 0 to -0.40. Age explained alone 49.6% of the variance of % BCPs/total cells, while “laboratory” explained 5.2% and panel used explained only 0.8%. Age explained only 24.9% of the variance of BCPs/CD34+ cells.
| % total CD34+ cells | BCPs/total cells | BCPs/CD34+ cells | |
0-6 years (n=10) | 3.05% (1.5 - 5.1) | 2.8% (0.35-3.8) | 62.1% (22.8-62.6) |
7-18 years (n=19) | 1.43% (0.25 – 3.2) | 0.4% (0.02-1.8) | 41.5% (3.1-64.5) |
19-55 years (n=70) | 0.84 (0.07-2.76) | 0.13% (0.02-0.8) | 20.8% (2.6-60.4) |
>56 years (n=35) | 0.71% (0.06-2.48) | 0.08% (0.02-0.68) | 12.9% (1.3-55.2) |
Conclusion
in a normal population BM B-cell precursors varied mainly with age, but were also dependent on technical peculiarities of operators and equipments. Analysis by phenotype and as percentage of total cells was more accurate and less susceptible to variation.
Session topic: 23. Hematopoiesis, stem cells and microenvironment
Keyword(s): B cell subsets, flow cytometry, Bone Marrow