"Monocytic" Cells of Normal Blood, Schilling and Naegeli Leukemia, and Leukemic Reticuloendotheliosis in Slide Chambers

1. The study of living blood cells in slide chambers by phase microscopy and cinemicrography adds useful morphologic, developmental and physiologic data complementary to other methods for studying blood cells.

2. Normal monocytes were characterized by flattening in fresh serum with minimal ameboid motility, by ectoplasmic veils waving in the medium, and by transformation to fully developed macrophages in 5-7 days.

3. Cells from four patients with acute monocytic leukemia (Schilling type) showed only slight differences in morphology, development and function from normal monocytes in the slide chamber.

4. Monocytoid cells from four patients with myelomonocytic leukemia (Naegeli type), in the slide chamber, resembled those from two patients with leukemic reticuloendotheliosis in morphology, development and function, but differed from normal monocytes and cells of acute monocytic (Schilling) leukemia. The monocytoid cells were labeled "reticulum" cells with the implication that they were related to the primitive hematopoietic reticulum cell.

5. The "reticulum" cell in the slide chamber differed from the monocyte in having a coarse nuclear chromatin pattern with clumping of chromatin, larger numbers of varying sized cytoplasmic granules, less ectoplasm, development of characteristic star-shaped macrophage forms without ectoplasmic veils, and in exhibiting a considerable ameboid motility as opposed to the sluggish veil waving of the monocyte.

6. Speculation as to the significance of the "reticulum" cell has been presented with the suggestion that this cell precedes the blast cell in hematopoiesis. In Naegeli leukemia, unknown factors may cause alterations in the type of cell released from the marrow. There may also be shifts in emphasis between myeloblast and pre-myeloblast proliferation which become reflected in the cells appearing in the peripheral blood.