[Suppression of tumor immunity by electromagnetic fields and glucocorticoids in mice with implanted Ehrlich carcinoma].
BACKGROUND
The immune system plays a major role in the origin, growth and evolution of tumors; factors that decrease the immune response in any way can cause higher tumor incidence and its faster or uncontrolled growth and evolution.


METHODS
The research included 18 healthy male Han: NMRI mice, weighing between 25 and 30g, with ten-day-old tumor deposits, divided into three groups consisting of six mice each. The first group was continuously exposed to extremely low frequency electromagnetic fields (intensity 70-320 microT). The second group was treated with high doses of corticosteroids (dexamethasone). The control group was not treated with corticosteroids, nor was exposed to extremely low frequency electromagnetic fields. The exposure period lasted for ten days. The criteria used to evaluate tumor immunity were: histological findings of leukocyte infiltration around the tumor cells and white blood cell count.


RESULTS
The control group presented with excellent immune response to tumor cells. Lymphoplasmacytic infiltrates widely surrounded the tumor. Numerous tumor cells showed signs of cell death. The results showed that exposure of animals to high doses of glucocorticoids resulted in extremely decreased leukocyte infiltration in the tumor tissue (single lymphocytes), while exposure to extremely low frequency electromagnetic fields significantly decreased leukocyte infiltration in comparison to the control group. Comparison of white blood cell count in treated groups revealed that the white blood cell count in both treated groups was decreased, compared with the control group.


CONCLUSIONS
Extremely low frequency electromagnetic fields significantly suppress the immune response to tumor cells. Dexamethasone treatment resulted in almost complete absence of immune response to tumor cells. Electromagnetic fields and dexamethasone both decrease the white blood cell count.
Knezević
Dusko
D
Medicinski fakultet Novi Sad.