80 The Lymphocyte and Lymphocytic Tissue 



tinguishable from other connective tissue macrophages. The hypertrophy 

 of these cells is accompanied by morphologic changes. If the study of 

 the inflammatory process had begun after the 25 hour stage interval, it 

 would be difficult to demonstrate lymphocytic origin of the macrophages. 



During the period of transformation, the lymphocyte develops an in- 

 crease in cytoplasmic and nuclear mass. This is accompanied by evidence 

 of increased phagocytic ability and a marked change in the appearance 

 of the nuclear pattern. The nuclear membrane becomes increasingly 

 irregular, the coarse chromatin particles are divided into smaller angular 

 pieces, and there is an increase in parachromatin. The latter is due in part 

 to an increase in the number of mitochondria and other cytoplasmic consti- 

 tuents. The blister-supravital technique confirms these findings by the 

 continuous direct observation of these changes on individual cells. 



Phagocytosis by small lymphocytes per se has been documented. Al- 

 though poor, this ability is genuine. The small amount of cytoplasm is one 

 limiting factor. It is of interest that in the area of inflammation, they often 

 show an increase in phagocytosis that is greater than the proportional in- 

 crease in cytoplasmic mass. 



Although this may be related to the various cytochemical changes, such 

 as the increase in mitochondria, the specific relation to these alterations 

 has not been clearly defined. 



The number of leukocytes in the peripheral blood will affect the quality 

 and quantity of the inflammatory exudate. In the patient with monocytic 

 leukemia, as well as in animals with a monocytosis, if monocytes are 

 present in sufficient number, they can represent the chief source of hemato- 

 genous macrophages. The nuclear changes characteristic of monocytes, 

 their increased si/e, precocious phagocytosis, etc., are evident during the 

 early hours of the response. Lymphopenia, without a concurrent monocyto- 

 sis, will lead to a marked decrease in the number of lymphocytogenous 

 macrophages. Recently Page and Good 6 reported that in neutrophenic sub- 

 jects the entire leukocytic cycle is interrupted. Thus, the variations in 

 circulating leukocytes can markedly influence the chain of events in the 

 complex reaction to injury called inflammation. 



SUMMARY 



The lymphocytes play a dynamic role in inflammation. They partake in 

 many interrelated functions. In the defensive functions concerned with 

 phagocytosis, the lymphocytes are an important source of motile macro- 

 phages. The transformation of lymphocytes into macrophages in acute 

 inflammation has been described and discussed. 



