Journal of Gerontology 1971, Vol. 26, No. 1, 28—~-36 . Immunohematological Studies of Marshall Islanders Sixteen Years after Fallout Radiation Exposure’ Robert A. Conard, MD, Charles F. Demoise, PhD, oO x oF § 8= TV SPF a LUOSLMOSPSI SOFEM \ Oo z AHOLISOdSY oO oO sce o dnd. Ww307104 William A. Scott, and Michael Makar’ IX 1954 the people of Rongelap in the Marshall Islands were accidentally exposed to radioactive fallout during the atomic bomb testing program. Fortunately the exposure proved to be sublethal. Numerous reports have documented both the early effects of radiation on blood cells and skin (Cronkite, Bond, Conard, Shulman, Farr, Cohn, Dunham, & Brown- ing, 1955) and the late effects, particularly in regard to growth retardation of children and the development of thyroid nodules and malig- nancies (Conard, Sutow, Colcock, Dobyns, & Paglia, 1969). Among the many studies on this population, the investigation of the possibility that radiation causes premature aging had been of continuing interest, particularly because ’ such findings have been reported in irradiated animals (Furth, Upton, Christenberry, Benedict, & Moshman, 1954). Some 200 unexposed Marshallese people served as an excellent comparison population for these studies, since they are closely related and live in the same environment. For aging studies measurements were made during physical examinations on characteristics considered to be criteria of aging (Conard, 1960; Conard, Lowrey, Eicher, Thompson, & Scott, 1966). Among these were skin elasticity and looseness and hair grayness; accomodation, visual acuity, and arcus senilis of the eyes; hearing loss; nerve and neuromuscular function, vibratory sense, and hand strength; 1 Research supported by U.S. NIH Grant #HD 0199-03, * Medical Department, New York 11973. 28 Atomic Energy Brookhaven National Commission and Laboratory, Upton, responseto light extinction test and rapid movementtest, systolic blood pressure; and levels of blood cholesterol and body potassium (*°K). Most of these criteria showed varying degrees of correlation with age and afforded a means of arriving at a “biological age” score for each individual. However, none of the tests showed any significant indication of premature aging in the exposed group that might be associated with radiation exposure. During the past several years we have extended these studies to include an examination of some aspects of the immune status in the exposed and unexposed Marshallese populations which mightbe indicative of aging and/or radiation exposure. The present studies include measuring transformation and replication of circulating lymphocytes from phytohemagglutinin (PHA) stimulation in culture, quanti- fication of the various serum proteins by electrophoresis, immunodiffusion studies for immunoglobulin levels, and routine enumeration of peripheral blood elements. In contrast to results of previous studies some of the present tests showed differences in the exposed population compared with the unexposed group that mightbe interpreted as radiation effects. Therefore in this report the results in the unexposed population will be treated separately to determine the correlation of these criteria with aging in a normal Marshallese population. The results in the exposed group will then be compared with the unexposed group to evaluate possible radiation effects. The Medical Research Centre Brookhaven National Lal: Upton,.L: L, New York v