%0 Generic %1 gobba2013natural %A GOBBA, F %A KORPINEN, L %A BORELLA, P %A BARGELLINI, A %D 2013 %K Extremely Field Frequency Killer Low MF) Magnetic Natural average blood cells exposure lymphocytes occupational peripheral time weighted %T Natural Killer activity in Peripheral Blood Lymphocytes of Workers Exposed to Different Levels of Extremely Low Frequency-Magnetic Fields (ELF-EMF) %X Extremely Low Frequency -Magnetic Fields (ELF-MF) are considered as possibly carcinogenic to humans (Group 2B IARC). The mechanism(s) are still unknown, but some data suggests a possible role in promotion or progression. Natural Killer (NK) cells play a major role in the control of cancer development: an adverse effect by ELF-MF on NK function has been hypothesized. Within a large study on the ELF-MF exposure of more than 500 workers, we selected 54 workers exposed to different levels of ELF-MF in various activities, but not to known factors which interfere with the immune system. Individual exposure was monitored both at work and during non-working hours for 2 days using personal dosimeters; ELF-MF levels in the workers were expressed as Time Weighted Average (TWA) values. NK activity was also measured in peripheral blood lymphocytes (PBL) and expressed both as a percentage of the lysis at different ratios between effector cells (NK cells) and target cells (E:T ratios) and as the number of lytic units in 107 cells (LU/107 cells). In the entire group, the occupational exposure estimated as the mean of individual TWA during working hours, was 0.58 μT (SD 0.80). The mean TWA environmental exposure was 0.04 μT (SD 0.02), i.e. less than 1/10 of the occupational value. Accordingly, in the examined group, the relative contribution of the environmental component to the overall exposure was considered as scarcely significant, and given no further consideration. According to the occupational TWA levels, workers were classified as low exposed (26 subjects, TWA :::; 0.2 μT) and higher exposed workers (28 subjects; TWA > 0.2 μT). In the higher exposed workers, a trend to reduced NK activity was observed compared to low exposed, but the difference was not significant (p > 0.05). A subgroup of workers exposed to ELF-MF levels exceeding 1 μT (highest exposed workers; 14 subjects) was then selected, with no difference observed between the low and highest exposed subjects in the main personal variables. The NK activity in highest exposed vs. low exposed workers was compared: considering both E:T ratios from 12: 1 to 50: 1 and LU, a significant reduction in NK activity was observed. Multivariate analysis confirmed a significant negative correlation between exposure and LU, while no correlation was evidenced with other personal characteristics. Our results suggest that an occupational exposure to ELF-MF, at least at TWA levels that exceed 1 μT, may induce a reduction in NK activity in PBL. The biological significance of these changes is still to be elucidated, but ELF-MFs are considered possibly carcinogenic, and existing data suggests that they can act as promoters. Due to the role of NK activity in the host defence against cancer, the results obtained in this study in workers exposed to ELF-MF levels exceeding 1 μT are in agreement with this hypothesis. The results presented here need confirmation, therefore further investigation in this field is needed.

@conference{gobba2013natural, abstract = {Extremely Low Frequency -Magnetic Fields (ELF-MF) are considered as possibly carcinogenic to humans (Group 2B IARC). The mechanism(s) are still unknown, but some data suggests a possible role in promotion or progression. Natural Killer (NK) cells play a major role in the control of cancer development: an adverse effect by ELF-MF on NK function has been hypothesized. Within a large study on the ELF-MF exposure of more than 500 workers, we selected 54 workers exposed to different levels of ELF-MF in various activities, but not to known factors which interfere with the immune system. Individual exposure was monitored both at work and during non-working hours for 2 days using personal dosimeters; ELF-MF levels in the workers were expressed as Time Weighted Average (TWA) values. NK activity was also measured in peripheral blood lymphocytes (PBL) and expressed both as a percentage of the lysis at different ratios between effector cells (NK cells) and target cells (E:T ratios) and as the number of lytic units in 107 cells (LU/107 cells). In the entire group, the occupational exposure estimated as the mean of individual TWA during working hours, was 0.58 μT (SD 0.80). The mean TWA environmental exposure was 0.04 μT (SD 0.02), i.e. less than 1/10 of the occupational value. Accordingly, in the examined group, the relative contribution of the environmental component to the overall exposure was considered as scarcely significant, and given no further consideration. According to the occupational TWA levels, workers were classified as low exposed (26 subjects, TWA :::; 0.2 μT) and higher exposed workers (28 subjects; TWA > 0.2 μT). In the higher exposed workers, a trend to reduced NK activity was observed compared to low exposed, but the difference was not significant (p > 0.05). A subgroup of workers exposed to ELF-MF levels exceeding 1 μT (highest exposed workers; 14 subjects) was then selected, with no difference observed between the low and highest exposed subjects in the main personal variables. The NK activity in highest exposed vs. low exposed workers was compared: considering both E:T ratios from 12: 1 to 50: 1 and LU, a significant reduction in NK activity was observed. Multivariate analysis confirmed a significant negative correlation between exposure and LU, while no correlation was evidenced with other personal characteristics. Our results suggest that an occupational exposure to ELF-MF, at least at TWA levels that exceed 1 μT, may induce a reduction in NK activity in PBL. The biological significance of these changes is still to be elucidated, but ELF-MFs are considered possibly carcinogenic, and existing data suggests that they can act as promoters. Due to the role of NK activity in the host defence against cancer, the results obtained in this study in workers exposed to ELF-MF levels exceeding 1 μT are in agreement with this hypothesis. The results presented here need confirmation, therefore further investigation in this field is needed.}, added-at = {2021-02-12T13:05:41.000+0100}, author = {GOBBA, F and KORPINEN, L and BORELLA, P and BARGELLINI, A}, biburl = {https://www.bibsonomy.org/bibtex/284da714496e54812e1efae594ec7f614/ceps}, interhash = {5f67038a11d406feeb9592e036228f26}, intrahash = {84da714496e54812e1efae594ec7f614}, keywords = {Extremely Field Frequency Killer Low MF) Magnetic Natural average blood cells exposure lymphocytes occupational peripheral time weighted}, timestamp = {2023-12-21T15:14:13.000+0100}, title = {Natural Killer activity in Peripheral Blood Lymphocytes of Workers Exposed to Different Levels of Extremely Low Frequency-Magnetic Fields (ELF-EMF)}, year = 2013 }