Peridialytic Serum Cytokine Levels and Their Relationship with Postdialysis Fatigue and Recovery in Patients on Chronic Hemodialysis

Background: The etiology of postdialysis fatigue (PDF), an intermittent but debilitating fatigue occurring in 40-80% of chronic hemodialysis (HD) patients after HD treatment, is still unclear. In other illnesses, such as inflammatory diseases, mounting evidence points toward the involvement of the immune system in the development of fatigue symptoms. Altered serum levels of inflammatory cytokines have also been shown in chronic HD patients and positive associations between interleukin-6 (IL-6) and fatigue symptoms in general in this patient population have been recently reported. Therefore, we investigated whether fatigue specifically occurring after HD (PDF) or the time needed to recover from HD treatment (TIRD) were related to pre- and postdialysis serum levels of pro- and anti-inflammatory cytokines (i.e. IL-1β, IL-6, TNF-α and IL-10) or their intradialytic changes (if any).\r\nMethods: Serum levels of IL-1β, IL-6, TNF-α and IL-10 were measured immediately before and after HD in 45 chronic HD patients using commercially available kits on an ELLA™ automated immunoassay system. The presence and severity of PDF as well as TIRD duration were assessed by self-report measures.\r\nResults: Thirty-three patients (74%) reported PDF, with a median PDF severity index of 3.30 [IQR: 3.00-4.30] on a scale from 1 to 5. Median TIRD was 120 min [IQR: 60-480]. PDF severity correlated strongly with TIRD, rs=0.85, p<0.001. Only predialysis IL-10 serum levels significantly and positively correlated with PDF severity (rs=0.43, p=0.003). Postdialysis cytokine levels and their intradialytic changes were not significantly related to PDF or TIRD.\r\nConclusions: The present study does not support the hypothesis that the immune system may be involved in the development of PDF or TIRD. The positive, but counterintuitive relation between predialysis anti-inflammatory IL-10 levels and PDF severity warrants further research. However, the present findings do not necessarily undermine the previously found positive relationship between IL-6 levels and chronically fatigue experience in HD patients, as fatigue as response to treatment may have other determinants than a more chronically fatigue.