Pulsed electromagnetic fields enhance the induction of cytokines by peripheral blood mononuclear cells challenged with phytohemagglutinin.

We evaluated the effects of a 50-Hz pulsed electromagnetic field on the production of cytokines by both resting and mitogen-treated peripheral blood mononuclear cells. Our results demonstrate that after exposure of normal cells to EMFs for 12 h, the levels of neither interleukin-1beta, nor interleukin-2 were increased. Indeed, the concentration of tumor necrosis factor alpha decreased significantly immediately after the exposure period. The results were, however, markedly different when cells were stimulated with phytohemagglutinin immediately before the exposure to EMFs. In this case the levels of cytokines, measured 24 and 48 h after the treatment, were 630 +/- 440 pg/ml and 910 +/- 530 pg/ml for interleukin-1beta, 530 +/- 330 pg/ml, and 860 +/- 560 pg/ml for tumor necrosis factor alpha, respectively. These values were significantly higher (P < 0.05) when compared with the controls. Interleukin-2 levels were significantly higher at the end of the EMF exposure only in supernatants of phytohemagglutinin-stimulated cells and, as a consequence of this increase, the proliferation indexes also were significantly increased 48 h after the EMFs' treatment. The comparison between biological activity and the cytokine antigen present in our samples indicated that the amount of antigen was paralleled by an equal recovery of biological activity. This suggests either the absence of qualitative differences in these proteins or the impairment of both the transcriptional and translational processes.