Myeloid differentiation in long term culture of human peripheral blood

• Published in: Experimental hematology 2000-12, Vol.28 (12), p.1501-1501
• Main Authors: Bigi, Giuseppe, Vanoli, Massimo, Pomati, Mauro
• Format: Article
• Language: English
• ISSN: 0301-472X; 1873-2399
• DOI: 10.1016/S0301-472X(00)00585-3

The amount of blood cells in the body is under the control of humoral and cellular factors that are trying to maintain the homeostatic equilibrium through adaptive responses. Previous observations have induced us to study these phenomena in a more detailed way. 20–25ml of peripheral blood of three healthy subjects were cultured as described (1). The tissue culture medium is made of RPMI 1640, 10% of fetal calf serum and 1% of L-Glutamine: this medium does not contain any cytokine, growth or differentiation factors. After 45 days it was possible to observe into the culture the differentiation of round cells, Myeloperoxidase and Sudan black positive, α-Naphthyl Acetate Esterase negative indicating a myeloid phenotype. These cells are multiplying in vitro and their amount involved in the phenomenon is between 30–40%. Apparently they do not follow any differentiation lineage. Some time it is possible to observe in a cytospin preparation some eosinophils, but we could never observe a neutrophil or a basophil. These cells seem to persist in an immature state. The central question left behind, after the long time in culture, is about their origin. The role of different cells must be very critical: the way they react to each other must be relevant. The attempt to give an explanation would be consitent with precursor cells that survive into the culture, probably as a small lymphocyte morphology, then assuming their true morphology as soon as the microenviroment of the culture reaches the trigger point. This phenomenon appear to be quite similar to what we already described (1). While it seems to add more options to the myeloid lineage complexity it emphasizes the interplay of the cells and the cytokines they produce. It should be very interesting to find out “what” allows the cells to persist in their immature state. (1) Bigi G.: Stem Cells Activity in Human Peripheral Blood. Leukemia 1, 623–626: 1987.