oe : * OT ro te ae ex eli gS RR St . ar ‘#6 ‘ . stows ae ete Zia - am * ‘ a gale gy . ® + TON . BBA dineda ie ae Pe te Tas we Re aMit AB le ane Pada oF «out ~ P * Pe. . at a? 4 7 4 eeFR oa ie esathathads > * gp ce W. H. ADAMS: LATE MEDICAL CONSEQUENCES OF EXPOSURE TO RADIOACTIVE differences were noted in serum protein electrophoretic studies in 1957, 1974, or 1982. Lymphocyte counts were significantly lower in the exposed Rongelap population in 1985, but in most years this was not found. = Ophthaimologic Examinations In 1981 ophthalmologic examinations revealed the presence in several individuals of lesions compatible with ocular toxoplasmosis. Toxoplasma gondii is an intracellular protozoan whichis most commonly disseminated among humansvia cat feces or inadequately cooked pork. It elicits both humoral and cellular immune responses, and medical complications are more severe in those individuals with a suppressed immune mechanism. Because of the potential risk of toxoplasmosis to exposed persons, a serologic survey for Toxoplasma antibodies was performed in 1982 (Table 1) (17). It was determined that nearly 100% ofthe Marshallese population had been infected with Toxoplasma, a finding to be expected on the basis of investigations by others in tropical regions. However, neither antibody titers nor ocular examination provided evidence that the exposed population was at unusual risk for toxoplasmosis or its complications. Another ubiquitous and serious infection, particularly in tropical areas, is viral hepatitis, including hepatitis B. This disease was also evaluated by a serologic survey (Table 2) (18). Again, nearly 100% of Marshallese examined had evidence of past exposure to hepatitis B. However, neither antibodytiters or the presence of hepatitis B surface antigen suggested an increase in risk of 30 hepatitis B complications among the Rongelap exposed population when compared with the unexposed. Anotherclinical marker of immune competenceis the ability to respond to skin test challenge with several antigens. Therefore, a survey of skin test responsiveness to Mycobacterium a community, has shown ap; middle - Ailingnae; tuberculosis and Candida was undertaken (Table 3). No evidence was foundto indicate inadequacy of the delayed hypersensitivity response among the Rongelap population. F any cell type (8). ied (Figure 3). There has been no evidence to date of autoimmune disorders. Rheumatoid arthritis has yet to be diagnosed with certainty, and a survey for rheumatoid factor uncovered only one positivetiter, a prevalence of 0.4% compared to 4-40% reported for various age groups in the U.S. The relative scarcity of diseases of purported autoimmune etiology extends to thyroid disease as well. Radiation-induced thyroid hypofunction, diagnosed in several exposed Rongelap individuals, was 1 of exposed Marshallese rid not found to be increased amony Japanese A-bomb survivors. This difference reflects the larger allenges oftetanusloxc sed persons,although the radiation dose absorbed by thyroids of the Marshallese, a consequenceofingestion of radioiodines. The question arises as to whether thyroid hypofunction might also reflect some immunologic le primary response wa “ iral and a battery of vira damageto the thyroid. ‘That damage is mediated, in part, by circulating autoantibodies that are . oy . . . . : : : apparently cytotoxic. Antimicrosomal antibodies are important in the diagnosis of autoimmune stformed. ‘The Rongelap thyroiditis, a disease process commonly progressing to hypothyroidism. Antithyroglobulin . 1 “tanus > sc 1 Ss es tested. No significant Lo . . ore . . ‘ . . . . cop 7 . 277