Significance of the ratio of reticulocyte subpopulations in bone marrow and peripheral blood from patients with myelodysplastic syndromes

Analysis of bone marrow aspiration fluid using automated blood cell counters

Cytomorphological examination of aspirate smears remains the basic method to diagnose hematologic disorders and to evaluate treatment-related changes. Last-generation hematological analyzers can count, besides cells normally circulating in peripheral blood, some types of immature and abnormal cells, such as erythroblasts and immature granulocytes. The complex nature of bone marrow fluid, however, has prevented until now the routine utilization of blood cell counters in this area. Recent studies have shown the possibility of using bone marrow fluid as a substitute for peripheral blood for clinical tests in particular situations and for repetitive cytologic examinations in specific clinical and research fields.

Hematopoiesis in 3 dimensions: human and murine bone marrow architecture visualized by confocal microscopy

In many animals, blood cell production occurs in the bone marrow. Hematopoiesis is complex, requiring self-renewing and pluripotent stem cells, differentiated progenitor and precursor cells, and supportive stroma, adipose tissue, vascular structures, and extracellular matrix. Although imaging is a vital tool in hematology research, the 3-dimensional architecture of the bone marrow tissue in situ remains largely uncharacterized. The major hindrance to imaging the intact marrow is the surrounding bone structures are almost impossible to cut/image through. We have overcome these obstacles and describe a method whereby whole-mounts of bone marrow tissue were immunostained and imaged in 3 dimensions by confocal fluorescence and reflection microscopy. We have successfully mapped by multicolor immunofluorescence the localization pattern of as many as 4 cell features simultaneously over large tiled views and to depths of approximately 150 μm. Three-dimensional images can be assessed qualitatively and quantitatively to appreciate the distribution of cell types and their interrelationships, with minimal perturbations of the tissue. We demonstrate its application to normal mouse and human marrow, to murine models of marrow failure, and to patients with aplastic anemia, myeloid, and lymphoid cell malignancies. The technique should be generally adaptable for basic laboratory investigation and for clinical diagnosis of hematologic diseases.