Vogelaar L, et al. – The clinicians performed this study to compare various characteristics of the immune system in fatigued against non–fatigued patients with inflammatory bowel disease (IBD) in clinical remission. They found significant differences in immune profile between fatigued and non–fatigued patients with IBD in clinical remission, which pointed out to a chronically active and Th1–skewed immune system in patients with fatigue. Whether these immune differences were directly involved in the fatigue complaints via immune–to–brain communication pathways remained to be determined. Accordingly, further exploration of the underlying immune effects related to fatigue was warranted to determine potential treatment options.

• According to the Montreal classification, patients with IBD in clinical remission were phenotyped, and the checklist individual strength-fatigue (CIS-fatigue) was used to evaluate fatigue (CIS-fatigue ≥ 35).
• The clinicians used flow cytometry on peripheral blood samples to investigate differences in leukocyte subsets.
• Using enzyme-linked immunosorbent assay, the expression of various cytokines was determined in stimulated whole blood and serum samples.
• They evaluated differences between fatigued and non-fatigued patients with IBD.

• The clinicians included 55 patients in the fatigue group (FG) and 29 patients in the non-fatigue group (NFG).
• They found no differences in demographic and clinical characteristics between the groups.
• Compared with the NFG, flow cytometry data demonstrated a significantly lower percentage of monocytes (p = 0.011) and a higher percentage of memory T-cells (p = 0.005) and neutrophils (p = 0.033) in the FG.
• In the FG, whole blood stimulation demonstrated increased TNF-α (p = 0.022) and IFN-γ (p = 0.047).
• Compared with NFG, the median serum level was significantly higher for IL-12 (p < 0.001) and IL-10 (p = 0.005) and lower for IL-6 (p = 0.002) in the FG.