138 The Lymphocyte and Lymphocytic Tissue 



showed the proliferation of atypical cells.' 51 These were variable in appear- 

 ance and resembled reticulum cells, lymphoblasts, "splenic tumor cells" 

 of Rich, Lewis, and Wintrobe, and some even resembled Reed-Sternberg 

 cells of Hodgkin's disease. The atypical cells gradually became less common 

 in spleens of patients dying six weeks alter irradiation. 



Abortive recovery occurs in many types of cells. The best description and 

 explanation are given by Puck and Marcus. 43 They found that an isolated 

 HeLa cell irradiated in vitro with 600 r usually underwent four or five 

 divisions with the production of giant and other atypical cells which could 

 not divide. Presumably a similar process occurs in irradiated lymphoid 

 tissue and produces the stage of abortive recovery. It is not known whether 

 the abnormal mitoses and atypical cells in irradiated lymphoid tissue have 

 any relation to the development of postirradiation leukemia. 



Chronic Morphologic Changes in Lymphocytes 



Various types of abnormal lymphocytes may appear in the blood. These 

 morphologically altered lymphocytes differed from the degenerating cells 

 which develop during the acute destructive stage although the differentia- 

 tion is not always clear-cut. Dickie and Hempelmann observed an increase 

 in the number of refractile neutral red granules in supravitally stained 

 lymphocytes of individuals who received 1.5 r per month. 1 -' Watts and 

 Mathieson, however, were not able to find an increase of lymphocytes with 

 refractile cytoplasmic granules in the blood of persons treated with radio- 

 active iodine. ,! " 



Insrram and colleagues 1 * found in blood smears of cyclotron workers a 

 few lymphocytes with bilobed and double nuclei. The workers had re- 

 ceived exposures below the tolerance dose. Differential counts showed that 

 the workers had 7.5 binucleated lymphocytes per 50,000 white blood cells 

 as compared to 1.5 cells per 50,000 in control individuals. These cells were 

 considered to be the result of abnormal mitoses. In persons exposed to 0.2 r 

 per week, the number of binucleated lymphocytes were increased to 5.9 

 per 50,000 white blood cells as compared to 1.4 per 50,000 in control indi- 

 viduals. 13 These lymphocytes were also observed in mice exposed to only 2 r. 

 Lower doses were not tested. The incidence of these cells did not depend 

 on the dosage of irradiation between 2 to 75 r. The binucleated lympho- 

 cytes are the most sensitive indicator of radiation of lymphoid tissue, but the 

 cells are not specific for irradiation. Various other types of abnormal cells 

 have been described in irradiated men and animals: lymphocytes with 

 clover-leaf-shaped nuclei,- lymphoblasts, cells difficult to differentiate from 

 monocytes, 15 and even isolated and clumped reticular cells. 1 "' An unusually 



