Circulating erythroblast abnormality associated with systemic pathologies may indicate bone marrow damage

Background: The circulating rare cell population is diverse and rich in diagnostic information. Its characterization and clinical exploitation by cell-based liquid biopsy is an ongoing research task. Bone marrow is one of the major contributors to the peripheral blood rare cell population and, consequently, determines individual rare cell profiles thus depending on bone marrow health status. Bone marrow damage has been associated with aggressive or late-stage systemic diseases and egress of various bone marrow cells into the blood circulation. The association of quantity and heterogeneity of circulating erythroblast with bone marrow damage is of particular interest. Methods: Circulating CD71^high/CD45-/Hoechst^high blast cells from healthy, noncancer-and cancer-afflicted donors were enriched by CD45 depletion and analyzed by immunofluorescence microscopy. Results: A new finding of aberrant and mitotic circulating erythroid-like cells that appear similar across blood donors afflicted with various systemic pathologies is reported. Further presented is a classification of said erythroblast-like cells in nine subcategories according to morphological differences between phenotypically similar cells. Conclusion: Aberrant and mitotic bone marrow-derived rare circulating erythroid-like cells can be detected in the blood of afflicted individuals but not in healthy donors, suggesting the cause of bone marrow damage.