CLASTOGENIC FACTORS IN THE PLASMA OF CHILDREN EXPOSED AT CHERNOBYL

Clastogenic factors (CFs), as they were described previously in accide ntally or therapeutically irradiated persons, in A-bomb survivors and in liquidators of the Chernobyl nuclear power plant, were also detecte d in the plasma of Chernobyl-exposed children. A high percentage of pl asma ultrafiltrates from 170 children, immigrated to Israel in 1990, e xerted clastogenic effects in test cultures set up with blood from hea lthy donors. The differences were highly significant in comparison to children immigrated from 'clean' cities of the former Soviet Union or children born in Israel. The percentage of CF-positive children and th e mean values of the adjusted clastogenic scores (ACS) were higher for those coming from Gomel and Mozyr, which are high exposure sites (IAE A measurements), compared to those coming from Kiev. There was no corr elation between residual 137-Caesium body burden and presence of CFs. However, both measurements were not done at the same time (in 1990 and 1992-1994, respectively). Also no relationship could be revealed betw een enlargement of the thyroid gland and CF-positivity. CFs are not on ly observed after irradiation, but in a variety of chronic inflammator y diseases with autoimmune reactions. They were also described in the congenital breakage syndromes, which are hereditary diseases with the highest cancer incidence in humans. Whether the clastogenic effects co ntinuously produced by circulating CFs represent a risk factor for mal ignant late effects deserves further study and follow-up. Since CF for mation and CF action are mediated by superoxide radicals, prophylactic treatment with antioxidants may be suggested for Chernobyl-exposed ch ildren, whose plasma induces a strongly positive CF-test.