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Release of polymorphonuclear leukocytes from the bone marrow by interleukin-8
T Terashima1, D English, J C Hogg
1Pulmonary Research Laboratory, University of British Columbia, St. Paul's Hospital, Vancouver, Canada.
Blood
|July 29, 1998
Summary
Interleukin-8 (IL-8) rapidly mobilizes polymorphonuclear leukocytes (PMN) from bone marrow sinusoids into circulation. This study quantifies PMN release and transit time, revealing sinusoidal release as the primary mechanism for IL-8-induced granulocytosis.
Area of Science:
- Hematology
- Immunology
- Cell Biology
Background:
- Interleukin-8 (IL-8) is known to induce granulocytosis.
- The precise mechanism of IL-8-mediated polymorphonuclear leukocyte (PMN) release from bone marrow (BM) requires further quantification.
- Understanding PMN kinetics is crucial for inflammatory and immune response studies.
Purpose of the Study:
- To quantify the release of PMN from BM induced by IL-8.
- To measure the transit time of PMN through the BM after IL-8 administration.
- To identify the specific BM compartment from which IL-8 mobilizes PMN.
Main Methods:
- Rabbits received 5'-bromo-2'-deoxyuridine (BrdU) to label dividing PMN in BM.
- Intravenous IL-8 administration followed by monitoring of circulating PMN and BrdU-labeled PMN (PMNBrdU).
- Quantification of PMNBrdU in hematopoietic and sinusoidal compartments of the BM.
Main Results:
- IL-8 caused transient granulocytopenia followed by significant granulocytosis.
- Increased numbers of band cells and circulating PMNBrdU were observed post-IL-8.
- PMN transit time through mitotic and postmitotic BM pools remained unaffected.
- A decrease in PMNBrdU within the BM sinusoids indicated rapid release from this compartment.
Conclusions:
- IL-8 rapidly mobilizes PMN primarily from the bone marrow venous sinusoids.
- The sinusoidal pool of PMN is the main source for IL-8-induced granulocytosis.
- PMN transit time through the BM is not altered by IL-8, suggesting a direct mobilization mechanism.