Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002874 (aplastic anemia)
 5,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study we have analyzed the activity of Cyclosporin A (CsA) on the "in vitro" production of TNF and IL-3/GM-CSF as a preliminary basis for explaining the successful use of CsA in aplastic patients. Thus, 73 T cell clones, obtained by a limiting dilution technique from the peripheral blood and bone marrow of 3 patients with severe aplastic anemia (SAA), were studied for TNF and IL-3/GM-CSF production as induced by stimulation with 1% PHA plus 1 ng/ml TPA. Lymphokines obtained in this manner were then tested by biological assays. Twelve out of the initial 73 T cell clones were selected for the production of a large quantity of IL-3/GM-CSF and/or TNF. With these clones we studied the ability of CsA to inhibit TNF and IL-3/GM-CSF production, which was stimulated with specific monoclonal antibodies directed against the CD2 and CD3 surface antigens. TNF and IL-3/GM-CSF production displayed a different sensitivity to CsA inhibition. In fact, at 400 ng/ml CsA a residual production of IL-3/GM-CSF was present in all clones tested (CD3: 21.8% and CD2: 14.4% of the maximal IL-3/GM-CSF activity), while secretion of TNF was virtually abrogated at 100 ng/ml. Moreover, the mean ID50 for TNF production was significantly lower than that of IL-3/GM-CSF (CD2: p = 0.028, CD3: p = 0.01). Using specific anti-IL-3 and anti-GM-CSF monoclonal antibodies, we showed that only GM-CSF, and not IL-3, was resistant to CsA inhibition. In conclusion, these results may represent a possible explanation of the successful use of CsA in the treatment of some patients with SAA.
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PMID:Effect of cyclosporin A on T cell clones from severe aplastic anemia: differential sensitivity of TNF and GM-CSF production. 142 30

Chronic exposure of humans to benzene has been shown to have a cytotoxic effect on hematopoietic progenitor cells in intermediate stages of differentiation, which can lead to aplastic anemia and acute myelogenous leukemia. We studied the effect of hydroquinone (HQ), a toxic metabolite of benzene found in the bone marrow, on the human promyelocytic leukemia cell line (HL-60), which can be induced to differentiate to both monocyte and myeloid cells, and thus has been used as a surrogate for a granulocyte/macrophage progenitor cell. Exposure of HL-60 cells to noncytotoxic concentrations of HQ for 3 hours before induction with phorbol myristate acetate (TPA) caused a dose-dependent inhibition of the acquisition of characteristics of monocytic differentiation, such as adherence, nonspecific esterase (NSE) activity, and phagocytosis, but had no effect on cell proliferation. HQ appeared to be affecting maturation beyond the monoblast/promonocyte stages. HQ also prevented differentiation induced by 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]; however, the block occurred after the acquisition of adherence. HQ at concentrations that inhibited monocytic differentiation had no effect on differentiation to granulocytes, suggesting that the block in the differentiation of these bipotential cells is a step unique to the monocytic pathway. HQ was unable to prevent differentiation induced by the macrophage-derived cytokine, interleukin (IL)-1, a differentiation factor for cells of the monocytic lineage.
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PMID:Induced differentiation of HL-60 promyelocytic leukemia cells to monocyte/macrophages is inhibited by hydroquinone, a hematotoxic metabolite of benzene. 173 8