*3.4.4. Biomarker*

Oxidative stress is a condition in which there is increased amounts of reactive oxygen or nitrogen species. This condition is now recognized to be a prominent feature of many acute and chronic disease and even in normal ageing process. Lipid peroxidation was found to be one of the biomarkers to assess oxidative stress status in human disease including HIV [23]. A study done by Friis-Moller *et al*. [35] have shown that HIV-infected patients have oxidative imbalance early in the disease; low serum and tissue antioxidants and elevation of peroxidation products. Besides, high plasma levels of malondialdehyde (MDA), reduced plasma gluta‐ thione (GSH) and decreased superoxide dismutase activities were also found [36].
