31 duced immunological surveillance. Our interest in 100 sideration that impairment of immunityis thought | 30 Antibody response. Three years after exposure a 30 people were tested for antibody responseto pri- ob immunological capacity is related also to the con- | number of exposed and unexposed Rongelap mary and secondary tetanus toxoid inoculations, with a mouse used for toxin-antitoxin assay of serum.®* The difference between the exposed and unexposed groups was notsignificant. Blood ceil changes. The persistent lag in complete recovery of leukocytes was believed to reflect re- duced bone marrowreserve and therefore reduced immunological reserve. The apparent recent recovery of hemopoiesis in the exposed people to control levels may indicate an improvementin their immunological status. Table 18 shows that reductions in lymphocytes and platelets and an increase in sedimentation rates were correlated with in- creasing age in the Marshailese. [mmunoproteins. Immunoelectrophoretic analysis of serum proteins in 1962 showedneither a para- proteinemia nora typical picture of antibody deficiency syndrome,but a high frequency of someof the immunoglobulins was noted.!°** Compiement fixation studies showed the Marshallese to have antibodies to most viruses except Asian influenza (an epidemicofthis disease later occurred in 1972). The antibody titers appeared somewhatlowerin the exposed people. !° Theolder people had higherlevels of gamma globulins but slightly decreased albumin levels (1969). 13.59.60 Immunodiffusion studies showed that the rise in gammaglobulin levels was paralleled by an increase in immunogiobulin.t The increase in IgG moiety was the most pronounced,and it showed significantcorrelation with age (r=0,78). The increase in K light chains was also significantly correlated with age. The immunoglobulin levels were more depressed in the exposed group, particularly those of IgG, IgA, and L light chains (Table 18). However, by 1974 the gammaglobulin levels in the exposed people were nearly the same as in the unexposed (Table 19). Lymphocytefunction. Tests on the phytohemagglutinin (PHA) stimulation of lymphocytes cul*Dr. R.D. Stoner at BNL did these analyses. **Drs. R. Biidler and A. Hassig at the Swiss Red Cross Labora- tory did these analyses. *These studies were done by Drs. J.L. Fahey and R. Woods of the National Cancer [mmunoglobulin Center. 5005128 Percent aging to be associated with the aging process. 7 rr Combined weighted data* TT 2 Exposed e Unexposed = Combined with standard error means _ ° _ r= 0.99** y 30.51 +0.38 x+0.01 x? | ; 80/- : 50- - ) wb J | 30 “Coefficient for age a correlation of each criterion used to weight 99 scores before summing lO ' al 20 _ **Correiation with age 1 30 40 significant at 1% level | 50 60 70 7 poo. 80 90 Age Figure 23. Biological age scores.!2 tured from peripheral blood showed a definite de- crease of responsiveness with increasing age of the individual (Table 18 and Figure 24) but no definite difference between exposed and unexposed groups.°9-69 In a more recent study, acetylation of nuclei of PHA-treated lymphocytes was measured at various times as a function of lymphocyte trans- formation and of aging.5! Decreased acetylation of nuclei is associated with increasing age and is roughly parallel to the decrease in lymphocyte transformation. Total acetate incorporation in the nuciei duringthefirst hour of culture was corre- lated with acetylation of histones, but by 20 hr acetylation of other nuclear materials had also occurred. Chromosome counts. In 1969 chromosomecounts were made on PHA-stimulated lymphocytes cultured from peripheral biood from 78 unexposed and 27 exposed Rongelap peopile.® Both hypodiploid and polyploid levels were found to be related to the subject’s age. Females >50 and exposed males >50 had ~ 1.5 times as many hypodip- loids as did the younger subjects; polyploid levels were sharply reduced in ail subjects >50. Hy-