**5.3 Free radical cause lipid peroxidation**

Plasma malondialdehyde and glutathione levels have been used as a determinate of oxidative status in the chronic immunological disorders; systemic lupus erythematosus (SLE) is a complex [100]. 4-Oxo-2-nonenal (ONE) is a highly reactive aldehyde originating from the peroxidation of polyunsaturated fatty acids involved in the pathogenesis of autoimmune disorders [101]. The product of lipid peroxidation is 4-hydroxynonenal (HNE) that acts as specific marker of immunosenescence and aging-related disorders [102].
