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Functional defects in phagocytic cells from patients with iron overload
Abstract:
Phagocytic functions were studied in patients with iron overload. Phagocytosis of radiolabelled opsonised Staphylococcus aureus by mononuclear (MN) leucocytes and polymorphonuclear (PMN) leucocytes was measured in 15 and 16 patients, respectively. The intracellular killing capacity of MN and PMN leucocytes of seven and nine patients, respectively, and chemotaxis of PMN leucocytes of eight patients, were assessed also. These cellular functions were compared with phagocytic functions of controls tested on the same day, and with the normal ranges of phagocytic cell functions obtained with MN and PMN leucocytes from 48 and 59 healthy donors, respectively. One or more phagocytic functions were impaired in 62.5 per cent of the patients. Comparison of the various phagocytic functions in patients and simultaneously tested controls showed a significant decrease of the mean phagocytic capacity of the patients' MN and PMN leucocytes (P less than 0.015 and P less than 0.03, respectively), as well as the mean bactericidal activity of the MN leucocytes (P less than 0.05) and the mean chemotactic responsiveness of the PMN leucocytes (P less than 0.025). Patients with excess iron must be regarded as compromised hosts, not only because of the increased availability of iron for bacterial growth, but also because of the associated functional impairment of monocytes and granulocytes.
Insights
Patients with iron overload exhibit impaired phagocytic functions, compromising their immune response. This study highlights reduced monocyte and granulocyte activity in individuals with excess iron, increasing infection risk.
Area of Science:
- Immunology
- Hematology
Background:
- Iron overload can affect immune cell function.
- Understanding phagocytic cell performance in iron overload is crucial for assessing host defense.
Purpose of the Study:
- To investigate phagocytic functions in patients with iron overload.
- To assess the impact of excess iron on monocyte and granulocyte activity.
Main Methods:
- Measured phagocytosis of Staphylococcus aureus by mononuclear (MN) and polymorphonuclear (PMN) leucocytes.
- Assessed intracellular killing capacity and PMN leucocyte chemotaxis.
- Compared patient functions with healthy controls and established normal ranges.
Main Results:
- 62.5% of patients showed impaired phagocytic functions.
- Significant decreases observed in MN and PMN leucocyte phagocytic capacity.
- Reduced bactericidal activity of MN leucocytes and chemotactic responsiveness of PMN leucocytes noted.
Conclusions:
- Patients with iron overload have compromised immune systems due to impaired monocyte and granulocyte function.
- Excess iron not only promotes bacterial growth but also weakens cellular immunity.
- Individuals with iron overload are considered compromised hosts, susceptible to infections.