AVALIAÇÃO IMUNOLÓGICA DOS INDIVÍDUOS EXPOSTOS À RADIAÇÃO IONIZANTE DO 137Cs, NO ACIDENTE RADIOATIVO DE GOIÂNIA (BRASIL).

Abstract

On September 13, 1987, it happened in Goiânia the largest radioactive accident of the western hemisphere. A capsule containing Cesium 137 (137Cs), originating from an unit of radiotherapy, was violated contaminating more than 200 people and taking 4 individuals to death. From the beginning of the accident, the health of the involved individuals started to be a constant concern of the authorities and mainly of Leide das Neves Foundation created to support and to attend involved people. The present study had for objective to evaluate, in the exposed patients to 137Cs in the accident of Goiânia, if this exposition induced immunological alterations such as the production of anti-nuclear antibodies against HEp-2 cells and rheumatoid factor, alteration in the global counting of leukocytes and in the values of serum immunoglobulins (IgG, IgM and IgA). It is known that the exhibition to ionizing radiation induces damages to ADN, resulting sometimes in mutation, mainly in the cells that present larger mitotic activity, like cells of the skin, intestinal covering and hematopoietic organs. With base in studies in the exposed patients to 137Cs, starting from the evaluation of the frequency of mutations, the possibility of an increase of carcinogenesis risk was considered in those individuals. Data obtained in studies of other radioactive accidents as that of Chernobyl and atomic bomb of Hiroshima and Nagasaki, demonstrate that radiation, besides acute effects, induces bone marrow alterations, larger predisposition to cancer development, thyroid auto-immune disease, gastritis, infectious diseases, among other illnesses. It has been suggested that abnormalities in the immunological response contribute to the appearance of those diseases, as alterations in the proportions of T cells and B cells, in serum antibodies levels, in cellular response and even in the production of autoantibodies. In this study, exposed patients did not presented more reactivity to auto-antigens, and did not presented no significant positivity to rheumatoid factor. Moretheless, we observed an increase in the global leukocyte number/mm3 in exposed individuals and also an increase in IgM level in individuals exposed to the lesser doses of ionizing radiation.