Lim HB, Cook GG, Barker AT, Coulton LA (2005)

This study investigated the hypothesis that exposure to mobile phone-type radiation causes a nonthermal heat shock protein (HSP) response in human peripheral blood lymphocytes and monocytes".

Blood, collected from volunteers, was exposed to 900 MHz radiation. Three different exposure conditions were investigated:
1. Exposure for 4 hours at an SAR of 0.4, 2.0, or 3.6 W/kg to continuous wave (CW) radiation.
2. Exposure for 20 minutes, 1 hour, or 4 hours to CW radiation at SAR of 2 W/kg or to a GSM-modulated signal at an SAR of 0.4 W/kg.
3. Exposure to CW and GSM-modulated radiation were compared after an exposure of 4 hours at an SAR of 0.4 W/kg.

In each case sham-exposed cells were part of the experiment. Positive (heat-stressed at 42°C) and negative (kept at 37°C) control groups were incubated simultaneously in the same incubator.

Heat cause an increase in the number of cells expressing stress proteins (HSP70, HSP27), measures using flow cytometry, and this increase was dependent on time. However, no statistically significant difference was detected in the number of cells expressing stress proteins after RF-field exposure.