Objective      To identify the effect of electromagnetic irradiation on Th1/Th2 cytokine balance.     Methods      A total of 40 Kunming mice were randomly divided into sham control (n=5)

and irradiation groups (1

2

3

5

7

9 and 11 d after 90 mW/cm

2

electromagnetic irradiation for 20 min

n=5 for each time point). The mice were sacrificed at the above correspondingly time points respectively after exposure

and their blood samples and spleen tissues were collected. The expression levels of interferon-gamma (INF-γ) and interleukin-4(IL-4) were detected with RT-PCR for spleen tissues and ELISA for blood samples. The excursion of Th1/Th2 cytokine bala

nce induced by electromagnetic irradiation was analyzed.     Results     INF-γ expression was obviously raised by 90 mW/cm

2

electromagnetic irradiation. Its serum level reached a a peak in 5 d after exposure

with an increase of 135.5% compared with sham control group (P0.01). IL-4 expression had a drawdown tendency by 90 mW/cm electromagnetic irradiation

but it had no significant difference when compared with sham control (P0.05).     Conclusion     Electromagnetic irradiation at 90 mW/cm

2

leads to the Th1/Th2 cytokine balance deflect to Th1.