3H-thymidine autoradiography of the CSF cells in cases of non-neoplastic disease.

Human CSF cells in cases of non-neoplastic disease of the central nervous system (CNS) were examined in vitro by 3H-thymidine autoradiography. Immediately after withdrawl by lumbar or ventricular puncture, the CSF was incubated in a sedimentation chamber at 37 degrees C for 1 hr with an admixture of 3H-thymidine at a concentration of 1-2 muCi/ml CSF. In a few cases the CSF withdrawn was incubated in a glass tube in the same condition as in a sedimentation chamber, and the CSF cells were collected by centrifugation. The CSF cells collected were fixed in methanol and the microautoradiographic procedure was performed. Labeled CSF cells were found in 21 cases out of 22. The average labeling index of the total nucleated cells was 0.22% with the highest labeling of 0.74%. Almost all the labeled cells were thought to be medium to large sized lymphocytes and monocytoids. Peripheral blood was examined by a similar method and the results were compared with those of the CSF. It may be noteworthy that thre exist DNA synthesizing cells in the CSF even in a non-neoplastic state of the CNS, although the number is not large.