The main outcome measures were lipopolysaccharide-stimulated production of proinflammatory cytokines interleukin-6 ( IL-6 ) , tumor necrosis factor alpha ( TNF - ) , and interleukin-1 ( IL-1 ) , and scores on the Multidimensional Fatigue Symptom Inventory-Short Form ( MFSI-SF ) , the vitality scale from the Medical Outcomes Study 36-item Short Form ( SF-36 ) , and the Center for Epidemiological Studies-Depression ( CES-D ) scale .