Cytokine production ex vivo: effect of raised body temperature.
Level 3 - non-randomized controlled study
Non-randomized within-subject controlled crossover study in healthy humans
PubMed 7636320 · doi:10.3109/02656739509022469
What was done
Eight healthy volunteers underwent whole-body hyperthermia via a 39.5 °C water bath for 2 hours (elevating rectal temperature to 39.5 °C) and served as their own controls on a separate day during 2-hour immersion in thermoneutral water (34.5 °C). Blood samples collected before, during (at rectal temperatures of 38 °C, 39 °C, and 39.5 °C or matching time points), and 2 hours post-immersion were evaluated. Blood mononuclear cells were stimulated in vitro with lipopolysaccharide or phytohemagglutinin to measure IL-1α, IL-1β, TNF-β, and IFN-γ production in the presence or absence of indomethacin.
What was found
The abstract reports no absolute numeric concentrations. Whole-body hyperthermia did not alter stimulated production of IL-1α, IL-1β, TNF-β, or IFN-γ compared to thermoneutral immersion. Indomethacin addition significantly augmented ex vivo production of TNF-β and IFN-γ under both conditions; however, the indomethacin-augmented TNF-β response declined from baseline during hyperthermia compared to the control condition, while the indomethacin effect on IFN-γ showed no difference between conditions.
Why it matters
Passive heating to fever-range body temperature does not appear to directly suppress or enhance basic ex vivo cytokine synthesis in human mononuclear cells, though it may alter cellular responsiveness to prostaglandin modulation.
Limits
The study evaluated a very small cohort (n = 8) of healthy individuals only. The abstract does not report randomization of condition order, duration between trials, or quantitative measurements and confidence intervals.
Cited by
- contradicts Heating human subjects in a 39°C water bath elevates interferon and TNF levels, and monocytes exposed to LPS produced 10 times higher interferon at 39°C compared to lower temperatures.