Fatigue in patients with systemic lupus erythematosus: lack of associations to serum cytokines, antiphospholipid antibodies, or other disease characteristics.

OBJECTIVE: To determine if fatigue in patients with systemic lupus erythematosus (SLE) is associated with levels of serum cytokines, antiphospholipid antibodies (aPL), or other disease features.
METHODS: In a cross sectional study 57 Caucasian patients with SLE were subjected to clinical neurological examination and cerebral magnetic resonance imaging (MRI). Fatigue was evaluated by Fatigue Severity Scale (FSS) and disease activity by SLE Disease Activity Index (SLEDAI). Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 2 (IL-2), IL-6, IL-10, transforming growth factor-beta (TGF-beta), interferon-alpha (IFN-alpha), anticardiolipin antibody (aCL) IgG and IgM, as well as anti-beta2-glycoprotein I antibody (anti-beta2-GPI) IgG and IgM were analyzed by ELISA.
RESULTS: Four of 5 patients with SLE had fatigue (FSS score > or = 3). There were no associations between fatigue and any sociodemographic variables, medication for SLE, disease activity, cerebral infarcts, serum cytokines, aCL or beta2-GPI antibodies, or any routine hematological, biochemical, or immunological tests.
CONCLUSION: Fatigue is a common phenomenon in patients with SLE. There is no association to disease activity or other markers of disease or inflammation. Fatigue is a complex phenomenon, and cytokine involvement in brain tissue not reflected by cytokine serum concentrations in this study cannot be excluded. Alternatively, psychosocial factors may well be the dominant predictor of fatigue in patients with SLE.