Tnf Alpha As A Growth Factor In The Myelodysplastic Syndromes

It has been postulated that TNF alpha plays a dual role in myelodysplasia: triggering the extensive apoptosis which characterizes myelodysplastic (MDS) marrows and stimulating proliferation thereby contributing to the marrow hyperplasia which is also usually present. MDS marrow specimens were placed into liquid culture or were cloned in the presence or absence of TNF alpha with or without IL3. When added to liquid culture containing IL3, TNF alpha increased the number of cells in 4 of 6 cultures. TNF alpha directly stimulated proliferation in 3 of 4 marrows which produced clonal growth in vitro. Considering all of the culture studies together, TNF alpha stimulated the proliferation of almost one half of the marrows which were studied. The failure of this cytokine to produce stimulation in all of the cultures reflects the heterogeneity of the myelodysplastic states.