In vivo hematologic effects of recombinant interleukin-6 on hematopoiesis and circulating numbers of RBCs and WBCs

TR Ulich, J del Castillo, KZ Guo - 1989 - ashpublications.org
TR Ulich, J del Castillo, KZ Guo
1989ashpublications.org
Abstract Interleukin-6 (IL-6) administered as a single intravenous (IV) injection caused the
following changes in the peripheral circulation of rats:(a) a biphasic neutrophilia with an
initial peak at 1.5 hours and a second sustained wave of neutrophilia between four and 12
hours,(b) a mild lymphocytosis at 0.5 hours and a mild lymphopenia between 1.5 and four
hours, and (c) a reticulocytosis between 12 and 24 hours. The bone marrow showed no
significant changes at 1.5 hours, suggesting that the peripheral neutrophilia at that time is …
Abstract
Interleukin-6 (IL-6) administered as a single intravenous (IV) injection caused the following changes in the peripheral circulation of rats: (a) a biphasic neutrophilia with an initial peak at 1.5 hours and a second sustained wave of neutrophilia between four and 12 hours, (b) a mild lymphocytosis at 0.5 hours and a mild lymphopenia between 1.5 and four hours, and (c) a reticulocytosis between 12 and 24 hours. The bone marrow showed no significant changes at 1.5 hours, suggesting that the peripheral neutrophilia at that time is caused by demargination of intravascular neutrophils and not by release of marrow neutrophils. The bone marrow at 12 hours showed a mild left-shifted myeloid hyperplasia of myeloblasts and promyelocytes and a tremendous erythroid hyperplasia of intermediate and late normoblasts. The bone marrow at 24 hours showed a continued mild myeloid hyperplasia and striking erythroid hyperplasia. In conclusion, IL-6 in vivo acts as a stimulus for myelopoiesis and erythropoiesis and causes accompanying peripheral changes in the number of neutrophils, lymphocytes, and RBCs.
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