bomb,159.554 Some findings in the Japanese tend to support radiation etiologyinthis Marshallese boy. Ia his case the latent period was quite lung, but the in- cidence of leukemia in Japan is sull (after > 25 years) higher amony the exposed group than among the general population. iso, the iculence has been higher among those exposed in chiide hood, particularly males, in whom the granulocyte fort of leukemia bas been pres alent: and the supe forihas been more presalout in cases with banger latent periods and lower exposures!?2 On the basis of 2 cases per year per million people per rad among the exposed Japanese, the expectancy among the exposed Manrhailese would be a total of about 0.33 cases. However, the normal incidence of leukemia in the Marshallese, from the sketchy statistics available, appears to be low, about 20 Cases per vear per tuillion compared with 60 to 7U in the U.S.. thus the nuriber of spontaneous cases expected alnong the expuscd Afarshallese would be a total of 0.02 to 04007, Whe ratio of radiation. induced to spontaneous expectancy (0.35:0.02 of 0.33:0.067) indicates that chances are about 3 to 13 tines as vreat that this Marshallese case was radianion-induced as that i was spontancous, Review of the hematological data on subject No. 34 over the 18-year period before the develop. nent of deukeiuia is of interest. The greater degree of hematologic depression in hin thaw inthe other exposed bova indicates cither a greater radiation dose to the hematapaictic tissues or greater scusie Livity oF proclivily to marrow depression. (None of the peripheral granulocyte levels in the other boys, exposed or unes posed, ploticd individually, were as low as his.) Perhaps his radiation dose was actually greater, since he was the vounuest Ron clomonacytic leukemias.” Vhe syndrose ts characterized by various findings, not all necesily precnt such asaaiuiia with erychrocyle aboard ies, Thrombocytopenia, atypical platelets in the petipheral blood, and neutropenia. + Chrome. solne abnormalities are reported in about half the cases. 195 fsolated neutropenia is an occasional pre- kukemic finding; in the case reported here, the relative neutropenia is the only finding that might be considered as preleukemic. I the preleukemic phase is considered to date back te near the tine of radiation exposure in this case, then it had a longer course thats is usually nated. 4 The possibility thatthe granulocytic reserve was reduced io subject No. 3d asa resale of radiation exposure was indicated by his granulocyte respute being lower than that af his peers ia response to challenge by childhood infections. One might spec. Ulite that the frequent infections to which the Macsbatles: are exposcd may have played a role in accelerating the deselupaient of a radiation. induced mutant lewkemic clone, Vhis would be similar in some wave to the role thought to be played by the thyroidestuuulating barmone in en: hancing the development of tumors in rachationinjuced thyroid: glands, as has been seen in the Marshallese vears afier exposure of their thyroid thank to radioiadine from the fallout. The above in closer contact with the Cillout source on the findings do net rule out the possibility of a viral cliologyfor this leukemia. radimensitivity. kemia, complete hematological examinations on gelap child exposed and may therefore have been ground. Being younger might alsa imply greater Ta view of the later development of the granulucytic formof leukemia, it is of interest that the carly bone marrow injury was characterized by having the greatest effect on the granulocytes, with the thrambocytic and lymphocytic cells less af fected and the erythrocytic cells least. "The erythrocytic system did not show evidence of failure until Because of the development of this case of leu. the exposed Marshatiose population are now belig carcied out sciniannually tastead of annually, B. OTHER MALIGNANCIES Malignancies ather than thyroid cancer and leukemia (see ‘Table 35) appeared to have a higher ok el near death. In spite of the long-teran findings, worbid evidence of the disease: was not apparent until the last few sont, One year before tbe dig. mais Of leukemia the peripheral blood cells appeared normal except for a possible increase in atypical monocytes, A preleukemic syndrome has been described for acing cascs of panlyinphoacytic leukemias. (4154 Linnan and Saarni!?* state that the frequency of the syndrome may be as high as two cases in five and that prelcukemie findings “reflect the carly sage of tayeloprolilerative disorders which will eventually fulfill the eriteria to be cliwsiticd as my. iin Gents after radiation treatment for ankylosing spondy titis,?#* etc.), and its etiological role was established without question by the high incidence of leukemia ia the Japanese exposed to the atom