30 CONARD, EMOISE, SCOTT, AND MAKAR REsULTs The results are summarized in Table 2, and correlation was due to differences between the younger (15-50 years) and older age groups as a function of age in Figures 1 through 4. Most of the changes noted generally reached a maximum effect in the 40- to 50-year-age group with little further change in the older groups. Therefore most of the age-dependent Response of lymphocytes to phytohemagglutinin stimulation.—The transformation of lymphocytes into blast forms as a result of PHA stimulation in peripheral blood cultures showed a decreasing response with increasing age (Fig. 1) which was well correlated with age (r= 0.89). Lymphocyte cultures in the exposed group showed nosignificant differences from the unexposed group in response to PHA stimulation (p> 0.68). Peripheral blood elements~—-The changes in various blood elements as a function of age: are presented in Tables 1 and 2. In the unexposed population the decreases in lymphocyte levels showed the greatest correlation with age (r=0.91) and appeared to reach a maximum in the 50- to 60-year age group. Slight depressions the values of the various criteria are plotted Table 2. Criteria Correlation with Age and Radiation Exposure. Criterion Unexposed Group Exposed Group Correlation §=-% % dif. with from Change Age UnexSignificance with Age (r Value) posed (p Value) Lymphocyte transformation decrease 0.89 -— 1.1 68 Serum proteins Total serum proteins Albumen Total globulins Alpha-i Alpha-2 Beta Gamma increase decrease increase increase increase increase increase 0.35 0.45 0.58 0.37 0.43 0.32 0.75 — 1.5 +15.0 —17.1 —31.0 —20.0 — §.0 18.3 24 ol 01 ol o1 cs) 0.1 Immunoglobulins A(igaA) D(IgD) M(IgM) G(IgG) Kappa light chains Lambdalight chains K/L ratio increase increase increase increase increase increase increase 0.49 0.20 0.20 0.78 0. 96 0,24 0.41 —17.0 — 3.0 — 4.0 — 8.0 — 3.0 —14.0 + 0.4 05 98 74 22 69 16 T4 Blood findings Hematocrit Sedimentation rate Total jeukocytes Lymphocytes Neutrophils Platelets decrease Inctease decrease decrease increase decrease 0.57 0.72 0.43 0.91 0.44 0.65 + 2.9 +14.4 — 2.5 — 0.1 —13.8 — 8.4 07 08 59 61 04 04 \N VITRO TRANSFORMATION 8a [ ] | f T Ty T z 2 a = oe oO oe Ww =z a oe ee - oa c s i i 30 oo UNEXPOSED ¥270.20-0.16X @---@ EXPOSED 12 72.47 - 0.24% 7 | 20 7 | Le iO 7 ! 20 I 30 I 40 L 50 AGE | 60 ! 70 80 Fig. 1. Age-related change in lymphocyte transformation in peripheral blood cultures showing the mean percentage transformation for each decade with standdrd deviation. (beyond 50 years of age). in platelet counts, white blood counts, and hematocrit were noted but were less strongly correlated with age. An increase in sedimentation, however, was fairly well correlated with age. In the exposed population the meanlevels of neutrophils and platelets were significantly depressed (p<.0.04) below levels of the unexposed population particularly in the older age groups (see Table 2, Fig. 2). The other blood findings were not notably different. Serum protein patterns—The results for serum protein studies as determined by electrophoretic analysis are shown in Figure 3 and Table 2. A slight increase was noted with increasing age in the unexposed Marshallese, but it was notstatistically significant. The gamma globulins increased significantly in older people. Alpha and beta globulin levels tended to show some increases although the correlation with age was notsignificant. Albumen levels tended to decrease slightly in older people. Pronounced differences were noted in the exposed population. The albumen levels were significantly higher and the globulin levels significantly lower than in the unexposed group. Alpha 1, Alpha 2, and gamma globulins showed the most pronounced depression in the exposed group (Table 2). Serum proteins, particularly gammaglobulins showed greatest deficits in the older exposed age groups. The results of the immunodiffusion studies are shown in Table 2 and in Figure 4. Parallel to the increase in serum gamma globulin levels, the immunoglobulins showed increasing