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Updated: Aug 8, 2026
Femoral Bone Marrow Aspiration in Live Mice
Published on: July 5, 2014
Visualizing the marrow granulocyte reserve
Abstract:
The MGR, the pool of band and segmented neutrophils from which sudden demands for extra blood neutrophils are met, has been studied by measuring blood neutrophil increments following administration of endotoxin, corticosteroids, or etiocholanolone. Alternatively its size may be estimated from marrow differential counts with or without estimates of marrow mass. In 34 studies of 31 patients with diverse causes of neutropenia, measurements were made of the MGR comparing endotoxin response and differential counts of marrow aspirates coupled with estimates of absolute marrow mass derived from EIT rate. Responses to endotoxin were normal in 10 studies and subnormal in 24. The factor which best predicted endotoxin response was the percent of marrow neutrophils and neutrophil precursors which were band and segmented forms. All responders to endotoxin had greater than 25% marrow neutrophils and neutrophil precursors that were band and segmented; 20 to 21 subjects with less than a normal response to endotoxin had less than 25%. These studies suggest that no further information is gained by measuring endotoxin response in neutropenic patients who have a reduced percent of band forms and segmented neutrophils in marrow aspirates.
Insights
The marrow granulocyte reserve (MGR) was assessed in neutropenic patients. Marrow differential counts, specifically the percentage of band and segmented neutrophils, effectively predict endotoxin response, simplifying MGR assessment.
Area of Science:
- Hematology
- Immunology
- Cell Biology
Background:
- The marrow granulocyte reserve (MGR) is crucial for meeting sudden demands for blood neutrophils.
- Assessing MGR traditionally involves measuring blood neutrophil increments after stimuli or estimating marrow size.
- Neutropenia, a condition of low neutrophil count, necessitates understanding MGR function.
Purpose of the Study:
- To evaluate the MGR in patients with neutropenia.
- To compare MGR assessment methods: endotoxin response vs. marrow differential counts.
- To identify predictors of endotoxin response in neutropenic individuals.
Main Methods:
- Conducted 34 studies on 31 patients with diverse causes of neutropenia.
- Measured MGR by comparing endotoxin response with marrow differential counts and estimated marrow mass.
- Analyzed the correlation between marrow neutrophil precursor percentages and endotoxin response.
Main Results:
- Endotoxin responses were normal in 10 studies and subnormal in 24.
- The percentage of band and segmented neutrophils and their precursors in the marrow best predicted endotoxin response.
- Marrow neutrophils and precursors >25% (band and segmented) correlated with normal endotoxin response; <25% correlated with subnormal response.
Conclusions:
- Marrow differential counts, specifically the percentage of band and segmented neutrophils, are reliable indicators of MGR.
- Measuring endotoxin response provides no additional information when marrow aspirates show a reduced percentage of band and segmented neutrophils.
- Simplified MGR assessment is possible using marrow differential counts in neutropenic patients.
