HUMAN NATURAL-KILLER CYTOTOXIC ACTIVITY IS NOT AFFECTED BY IN-VITRO EXPOSURE TO 50-HZ SINUSOIDAL MAGNETIC-FIELDS

Epidemiological studies have suggested, but not demonstrated, a role o f exposure to 50/60-Hz magnetic fields in increasing cancer risk in ma n (workers and the general population). A possible target of magnetic fields is the immune system. In particular, it is known that an import ant defence against cancer is represented by natural killer (NK) cells capable of killing cancer cell targets. To test this hypothesis, huma n NK cells, stimulated or not with phytohaemagglutinin or interleukin 2, were exposed to 50-Hz sinusoidal magnetic fields before or during t he cytotoxicity test, and then mixed with a variety of target cancer c ell lines (Daudi, Raji, U937, H14, IGROV, SW626, K562, HL60). The expe riments were performed in two laboratories (Rome and Modena) by means of two different exposure systems. The results of both laboratories su ggest that 50-Hz sinusoidal magnetic fields with flux densities up to 10 mT do not affect the cytotoxic activity of human NK cells.