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Oxygen radical release by neutrophils of HIV-infected patients
1Department for Clinical Microbiology, Huddinge University Hospital, Sweden.
Abstract:
Neutrophils from asymptomatic HIV-infected patients have an increased Nitroblue tetrazolium (NBT) reduction, that is an increased production of oxygen radicals. Plasma from these patients can activate normal neutrophils to an increased NBT-reduction and the neutrophil activating factor thus seems to be mainly plasma bound. Further, the patients also have increased levels of plasma malondialdehyde and thus an increased lipid peroxidation. Plasma cysteine levels are low, a sign of increased consumption of antioxidants. Treatment of the asymptomatic HIV-infected patients with N-acetylcysteine corrected the plasma cysteine levels and had some beneficial effects, but did not inhibit the increased radical production by the neutrophils.
Insights
Asymptomatic HIV patients show increased neutrophil radical production and oxidative stress. N-acetylcysteine treatment improved antioxidant levels but did not reduce neutrophil hyperactivity, suggesting ongoing oxidative damage in HIV infection.
Area of Science:
- Immunology
- Infectious Diseases
- Biochemistry
Background:
- HIV infection is associated with immune dysregulation and oxidative stress.
- Neutrophils play a critical role in the innate immune response and can contribute to inflammation.
- Oxidative stress, characterized by an imbalance between reactive oxygen species and antioxidants, is implicated in HIV pathogenesis.
Purpose of the Study:
- To investigate neutrophil function and oxidative stress markers in asymptomatic HIV-infected individuals.
- To explore the role of plasma factors in neutrophil activation in HIV.
- To evaluate the impact of N-acetylcysteine (antioxidant) supplementation on neutrophil function and oxidative stress in HIV.
Main Methods:
- Assessed Nitroblue tetrazolium (NBT) reduction in neutrophils to measure oxygen radical production.
- Measured plasma malondialdehyde (MDA) as a marker of lipid peroxidation.
- Quantified plasma cysteine levels as an indicator of antioxidant status.
- Administered N-acetylcysteine to patients and re-evaluated parameters.
Main Results:
- Neutrophils from asymptomatic HIV patients exhibited increased NBT reduction, indicating heightened oxygen radical production.
- Plasma from HIV patients could activate normal neutrophils, suggesting a plasma-bound activating factor.
- Elevated plasma MDA levels indicated increased lipid peroxidation.
- Low plasma cysteine levels suggested increased antioxidant consumption.
- N-acetylcysteine treatment normalized plasma cysteine but did not inhibit increased neutrophil radical production.
Conclusions:
- Asymptomatic HIV infection is characterized by neutrophil activation and increased oxidative stress.
- Plasma factors in HIV-infected individuals contribute to neutrophil hyperactivity.
- While N-acetylcysteine improves antioxidant status, it does not fully resolve the neutrophil oxidative burst in HIV, highlighting the complexity of oxidative stress in this condition.