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The increase of low density subpopulations and CD10 (CALLA) negative neutrophils in severely infected patients
T Morisaki1, T Goya, T Ishimitsu
1First Department of Surgery, Kyushu University School of Medicine, Fukuoka, Japan.
Abstract:
We investigated the changes in polymorphonuclear leukocyte (PMN) subpopulations that accompany severe bacterial infection and examined their usefulness as a parameter for assessing the severity of infection. The Percoll density gradient was used to fractionate neutrophils into subpopulations of high density (1.09-1.10), intermediate density (1.08-1.09), and low density (1.07-1.08) with the majority of neutrophils from normal volunteers being of high density. By contrast, neutrophils from infected patients were of intermediate or low density, while those from severely infected patients showed a high percentage of the low density fraction with functional changes in lower chemotactic and beta-gulcuronidase activity. When each density subpopulation in the normal blood neutrophils was tested, low density PMNs had the lowest chemotaxis and minimal beta-glucuronidase activity. These results indicate that the increase in low density PMNs in patients with severe infection clearly reflects the functional impairment of PMNs. Flow cytometric analysis demonstrated that the neutrophils from severely infected patients had an decrease in CD10 expression. The percentage of CD10 positive PMNs correlated well with the severity of infection and with the clinical course of the patients. Thus, we conclude that PMN-density and CD10 expression change during severe bacterial infection, and that the measurement of PMN-subpopulations may be used to complement the clinical assessment of the severity of infections.
Insights
Changes in polymorphonuclear leukocyte (PMN) subpopulations, specifically increased low-density PMNs and decreased CD10 expression, indicate functional impairment during severe bacterial infections. These changes can help assess infection severity.
Area of Science:
- Immunology
- Hematology
- Infectious Diseases
Background:
- Polymorphonuclear leukocytes (PMNs) play a crucial role in the immune response to bacterial infections.
- Understanding PMN subpopulations and their functional status is vital for diagnosing and managing severe infections.
Purpose of the Study:
- To investigate alterations in PMN subpopulations during severe bacterial infections.
- To evaluate the utility of PMN subpopulations as a marker for infection severity.
Main Methods:
- Fractionation of neutrophils into density subpopulations using Percoll density gradient.
- Assessment of neutrophil function, including chemotaxis and beta-glucuronidase activity.
- Flow cytometric analysis to determine CD10 expression on PMNs.
Main Results:
- Neutrophils from infected patients shifted towards lower density fractions compared to normal volunteers.
- Low-density PMNs exhibited reduced chemotactic and beta-glucuronidase activity.
- Severely infected patients showed a decrease in CD10 expression on PMNs, correlating with infection severity.
Conclusions:
- Increased low-density PMNs reflect functional impairment in severe bacterial infections.
- Decreased CD10 expression on PMNs serves as a reliable indicator of infection severity.
- Measuring PMN subpopulations and CD10 expression can complement clinical assessments of infection severity.