TNF and Apathy: Soluble forms ofTNF-α receptors represent reliable markers of this cytokine activity, bindingto and protecting TNF-α from proteolytic degradation, therefore, extendingits effects systemically.15 Wealso investigated the possible association between BDNF and apathy, since there hasbeen a previous report of reduced levels of this neurotrophic factor in subjectswith late-life depression,16 acondition that shares abulic features with apathy.