IL6 and systemic lupus erythematosus: The reduction of HRQoL in the absence of obvious physical manifestations may result from the persistent immune dysfunction in SLE; which contributes to the upregulation of proinflammatory cytokines, such as interleukin 6 (IL-6) and tumour necrosis factor α (TNF-α), which have been associated with fatigue, irritability, depressive moods and social withdrawal [14].