Ultrastructural and cytochemical characterization of human cord blood cells

As part of a study to identify the characteristics of cord blood cells, we examined their morphological features by electron microscopy. Additionally, we cultured CD34-positive cells derived from cord blood and from bone marrow to perform morphological observations, as well as cytochemical examinations following the peroxidase reaction. Compared with normal peripheral blood cells, cord blood cells frequently showed immature morphology and a unique ultrastructure, such as nuclear pockets in neutrophils, several crystalloids in a single eosinophilic granule, and deformed nuclei in lymphocytes. In contrast to bone marrow cells, cord blood cells yielded a large number of cells of immature myelo-monocytic lineages in cell culture, and demonstrated a weaker peroxidase reaction. We identified that cord blood cells were different from normal peripheral blood cells and bone marrow cells, confirming the functional differences that were previously assumed.