Lymphocyte and granulocyte enzyme activity in patients with Down's syndrome.

N UMEROUS REPORTS have been published demonstrating an increase in the activity of white blood cell enzymes among patients with trisomic Down’s syndrome.’ Hook and Engel2 have suggested that the level of enzyme activity is dependent upon cell age and that a shortened lifespan of the leukocyte in Down’s syndrome might result in the presence of younger white blood cells with higher enzyme levels. Two recent studies with conflicting results have attempted to answer this question. Gaibraith and Valberg,3 using the technic of labeling leukocytes in vitro with radioactive diisopropyl fiuorophosphate ( DFP32 ) to study the granubocyte half-life, the blood granulocyte mass, and the granulocyte turnover rate were unable to demonstrate any difference between normals and four patients with Down’s syndrome. On the other hand, Raab et al.,4 using comparable technics involving DFP32 labeling in trisomic Down’s syndrome, were able to demonstrate an increase in granulocyte turnover rate. In an attempt to demonstrate which white blood cell component might be responsible for the elevation in enzyme activities in Down’s syndrome, we have utilized the method of Rabinowitz5 in the separation of lymphocytes and granulocytes in Garvin’s glass bead columns.6