Adult Bone Marrow Three‐Dimensional Phenotypic Landscape of B‐Cell Differentiation

Abstract

Background: The different B-cell subsets in human bone marrow result from a dynamic equilibrium between endogenous production, B-cell bone marrow reentry and terminal plasma cell differentiation. Our aim was to define and quantify the different medullary B-cell subsets.Methods: A series of 32 normal adult bone marrows plus 15 normal adult blood samples was studied by nine color flow cytometry (CD10, CD19, CD24, CD27, CD34, CD38, CD45, IgM, and IgD). With the Kaluza software radar plots, two 2D triple parametric histograms (CD10/CD34/CD45 and CD27/IgM/IgD) were set-up to identify six progenitor and five mature B-cell subsets.Results: Very early B-cell progenitors were CD19neg/CD10pos/CD34pos. B-cell progenitors were split into five subsets on the CD10/CD34/CD45 triple parametric histogram, sequentially ordered according to the loss of CD34 and CD10 and acquisition of surface IgM and IgD. CD19pos/CD38low mature B-cells were divided into four subsets on the CD27/IgM/IgD triple parametric histogram, with two stages of naïve B-cells and two CD27hi marginal zone and switched memory B-cell compartments. CD19pos/CD34neg/CD10low immature B-cells were the main bone marrow B-cell subset, accounting for one third of bone marrow B-cells. Transitional B-cells were the only immature bone marrow stage found in the blood. Compared to blood, the bone marrow was enriched in both marginal zone and switched B-cells.Conclusion: We provide the first analysis of 3D B-cell differentiation by multicolor flow cytometry leading to propose reference values for each bone marrow and blood B-cell compartment. This warrants further exploration of normal and pathological human B-cell maturation.

B cell subset distribution in human bone marrow is stable and similar in left and right femur: An instructive case

“…In a recent report the B cell phenotypes in the BM have been assessed. Here, immature CD38 + B cells are described to represent one third of the B cells in the BM [13]. Adding other CD38-expressing cells such as transitional B cells provides comparable percentages as seen for CD27 - CD38 + B cells in our samples (42–44%).…”

“…Adding other CD38-expressing cells such as transitional B cells provides comparable percentages as seen for CD27 - CD38 + B cells in our samples (42–44%). In the report, CD38 - B cells divide into CD27- and CD27 + B cells with the CD27 + being the less frequent subset [13]. Gating the two samples for CD27 + CD20 + conventional memory B cells showed frequencies of 7.24% (left femur) and 9.29% (right femur), respectively.…”

Remembrance of Things Past: Long-Term B Cell Memory After Infection and Vaccination

“…In the blood and bone marrow, human memory B cells can be divided in three main populations: CD19 + CD27 + IgM + IgD + (similar to marginal zone (MZ) B cells), CD19 + CD27 + IgM + IgD − (IgM-ONLY) and class-switched CD19 + CD27 + IgM − (IgG + or IgA + ) (114, 115). An in-depth flow cytometry analysis of human bone marrow and blood samples showed that compared to the blood, the bone marrow was enriched in both MZ and switched B-cells (116). In the spleen, two main phenotypically distinct B cell populations exist and localize to separate areas of the lymphoid tissue.…”

From the Editor: Thank you! Remembrances and Issue Highlights

“…The review by Drs. Seegmiller, His and Craig, as well as the entire review series, are more fully described on the pages just following these by our two Guest Editors (9) Following the first review related to B-cell diagnostics, a greater understanding of how B-cells develop immunophenotypically is the inquiry behind the report by Carrion et al (10), a subject that has been touched upon in the journal's past pages (11,12). Using ninecolor flow cytometry, these investigators studied 32 normal adult bone marrows and 15 normal peripheral blood samples to define eight different B-cell stages in the bone marrow and five different stages in peripheral blood.…”