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Polymorphonuclear leucocyte dysregulation in patients with gram-negative septicaemia assessed by flow cytometry
C Wenisch1, P Parschalk, M Hasenhündl
1Department of Infectious Diseases, University Hospital of Vienna, Austria.
Abstract:
Flow cytometry was used to study phagocytic function and release of reactive oxygen intermediates (ROI) following phagocytosis by granulocytes in 14 patients (six female, eight male) with gram-negative septicaemia prior to, during, and after therapy compared with a group of healthy controls. Phagocytic capacity was assessed by measuring uptake of fluorescein isothiocyanate (FITC)-labelled bacteria. Reactive oxygen generation after phagocytosis was measured by the quantification of dihydrorhodamine 123 converted to rhodamine 123 intracellulary. Compared with results in healthy controls granulocytes of septicaemic patients exhibited a decreased capacity to phagocytize Escherichia coli and to generate reactive oxygen products. Both phagocytosis and ROI production increased after initiation of therapy and normalized within 7 days of treatment. The results suggest that granulocytes do not only participate in, but are also a target of, the septic host inflammatory response.
Insights
Granulocytes in patients with gram-negative septicaemia show impaired phagocytic function and reactive oxygen intermediate (ROI) release. Therapy improved these functions, suggesting granulocytes are both participants and targets in the septic inflammatory response.
Area of Science:
- Immunology
- Hematology
- Infectious Diseases
Background:
- Gram-negative septicaemia is a severe infection characterized by a systemic inflammatory response.
- Granulocytes play a crucial role in combating bacterial infections through phagocytosis and the production of reactive oxygen intermediates (ROI).
- The functional status of granulocytes during septicaemia and the impact of therapy are not fully understood.
Purpose of the Study:
- To investigate the phagocytic capacity and ROI production of granulocytes in patients with gram-negative septicaemia.
- To compare granulocyte function in septic patients with healthy controls.
- To evaluate the effect of therapy on granulocyte function during gram-negative septicaemia.
Main Methods:
- Flow cytometry was utilized to assess granulocyte function.
- Phagocytic capacity was measured by the uptake of fluorescein isothiocyanate (FITC)-labelled Escherichia coli.
- ROI generation was quantified by measuring the conversion of dihydrorhodamine 123 to rhodamine 123.
Main Results:
- Granulocytes from patients with gram-negative septicaemia demonstrated reduced phagocytosis of E. coli and diminished ROI production compared to healthy controls.
- Initiation of therapy led to significant increases in both phagocytosis and ROI production.
- Granulocyte function normalized within 7 days of treatment.
Conclusions:
- Granulocytes exhibit impaired function during gram-negative septicaemia, indicating they are affected by the septic inflammatory response.
- Therapeutic interventions can restore granulocyte phagocytic capacity and ROI generation.
- These findings highlight the complex role of granulocytes in sepsis, acting as both effector cells and targets of the host response.