Acute effects of recombinant human interleukin-6 on endocrine and central nervous sleep functions in healthy men.
Level 2 - randomized trial
Individual controlled crossover clinical trial in humans
PubMed 9589658 · doi:10.1210/jcem.83.5.4795
What was done
Sixteen healthy men participated in two 14-hour overnight sessions (1800 to 0800 h) receiving either placebo or subcutaneous recombinant human interleukin-6 (0.5 µg/kg body weight) at 1900 h in a controlled crossover design. Repeated blood draws were taken to measure plasma ACTH, cortisol, GH, TSH, C-reactive protein, and cytokines (IL-2, IL-8, IFN-α, IFN-γ). Nocturnal sleep recordings were collected from 2300 to 0700 h, along with assessments of mood and body temperature.
What was found
The abstract reports directions and p-values but no exact baseline or absolute numerical values: - IL-6 induced a prolonged increase in plasma ACTH and cortisol (P < 0.001) and decreased TSH concentrations (P < 0.01). - C-reactive protein concentrations markedly increased 12.5 h after administration (P < 0.001). - Slow-wave sleep decreased in the first half and increased in the second half of sleep, while REM sleep during the entire night was significantly decreased. - Body temperature rose slightly, and subjects reported fatigue, feeling more inactive, and reduced concentration capacity. - IL-6 did not alter serum concentrations of IL-2, IL-8, IFN-α, or IFN-γ.
Why it matters
This study provides experimental evidence in humans that acute IL-6 elevation directly activates the pituitary-adrenal axis, alters sleep architecture, and contributes to sickness-related behavioral changes.
Limits
The sample was small (n = 16) and limited to healthy young men. The abstract does not provide exact numerical effect sizes or confidence intervals, and only a single acute low dose was tested.
Cited by
- supports Interleukin-6 (IL-6) can directly re-trigger the hypothalamic-pituitary-adrenal (HPA) axis without the presence of an external stressor.