There is increasing evidence of an association of parathyroid adenomas and hyperparathyroidism with radiation exposure to the head and neck regions. !° Two persons from Utirik and one of the comparison population had mildly elevated serum calcium levels of 10.9-11.2 mg/dl. These are to be rechecked whenthe individuals appear for reexamination. There were no low serum albumin levels which could have resulted in the masking of hypercalcemia. ; Serum Protein Electrophoresis. Monoclonal increases in serum globulins can occasionally be benign, but they are also seen in association with myeloma, lymphoma, and solid tumors. No monoclonalspikes were found on serum protein electrophoresis. A decrease in gammaglobulin is a frequent finding in the lymphoproliferative disorders. The normal range for gamma globulin is from 0.50 to 1.40 g/dl. The lowest value found in the Marshallese was 1.20 g/dl. There were no significant differences in mean gamma globulin values among the exposure groups (Table 2). IMMUNE STATUS In 1957 thefirst of several tests for evaluating the immune function of exposed Marshallese was performed.” The serologic responses to primary-and secondary challenges of tetanus toxoid were found notto be significantly different between exposed and unexposed persons, although the range of titers was great, the number of persons tested was small, and the primary response was somewhat lowerin the exposed. In 1959 complementfixation tests fora battery of viral and rickettsial diseases (including influenza, mumps, and adenovirus) were performed. The Rongelap group had lower mean titers than the comparison group for most of the complement-fixing antibodies tested.'? No significant differences were noted in serum protein electrophoretic studies in 1957. In 1969, however, exposed persons had a mean gammaglobulin level 18.3% below that of the comparison group (p = 0.01).”” In 1974 this difference was not noted.'® The gammaglobulin levels measured in 1982, shown in Table 2, again reveal no statistically significant differences among exposure groups. Also included in Table 2 are the mean 1982 lymphocyte counts; the Ailingnae valuesare, by t-test analysis, significantly lower than that of the comparison group (p < 0.05). Ophthalmologic examinations in 1981 revealed the presence in several individuals of lesions compatible with ocular toxoplasmosis. Toxoplasma gondii is an intracellular protozoan which is most commonly disseminated among humans via cat feces or inadequately cooked pork.It elicits both humoral and cellular immuneresponses, and medical complications are more commonly severe in thoseindividuals with a suppressed immune mechanism.” Because of the potential risk of toxoplasmosis to exposed persons, a serologic survey for toxo- plasma antibodies was performed on 517 Mar- shallese sera collected at the time of the annual examinations in 1982. Table 2 Grouped values (+ SD) for serum gamma globulin and lymphocyte count, 1982. Nostatistically significant difference between exposed and unexposed groups was found for gamma globulin, but lymphocytes were lower (p <0.05) for the Ailingnae group(t-test). Ronegelap Ailingnae Utirik Comparison GammaGlobulin g/dl* (n) 1.91+0.41 (46) 1.81+0.24 1.98+0.45 (93) 1.96+0.48 (92) Lymphocytes/ ul (n) 2778791 (47) 1983+653 (10) 2865+904 (93) 2732+793 (99) *Normal range at Brookhaven National Laboratory — 0.50 to 1.40 g/dl.