-ll- not recognizable carly. It seems likely that the relative depression of the peripheral blood elements noted in the exposed Marshallese is probably a continuing manifestation of incomplete recovery of the hematopoietic injury originally sustained. Therefore if such an effect, is a part of the aging process, it has been present since exposure since we have noted continuing depression of blood elements on annual examinations. The significant depression of the serum globulins and increase in serum albumens in the exposed population is a notable finding. The derpression in the gamma and alpha globulins and particularly in the IgA moiety and to a lesser extent in the IgG group and the L light chains.would seem to indicate a reduction in relative immunological "capacity or at least lowered antibody reserves in the exposed people. The tendency for the depression of these moieties to be relatively greater in the older age groups may imply a radiation-induced aging effect. Since these _ . studies were not carried out earlier it is not possible to say when these changes developed. However, at 3 years post exposure the people were challenged with tetanus toxoid and primary and secondary responses were found not to be , significantly different in the exposed compared with the unexposed population (Conard, Meyer, Rall, Lowrey, Bach, Cannon, Carter, Eicher, & Hechter, 1958). Also in spite of slight depression of blood elements and reduced serum globulin levels the exposed Marshallese people, based on our observations over a 15 year period since the accident, have not been observed to have any recognizable impairment of immunological capacity based on the incidence or susceptibility to illness or diseases. Lf the serum protein changes are a recent development then such deficiency may yet become apparent if the people are faced with a virulent antigenic challenge in the future. |