Autoradiographic demonstration of proliferating cells in cerebrospinal fluid.

The proliferative activity of cells, isolated from 82 human CSF specimens, was examined by 3H-thymidine autoradiography. High labelling indices (LI) were found in acute viral meningitis (up to 8 per cent) and radiculitis (up to 6 per cent). CSF cell proliferation was also shown in the subacute stages of viral diseases and in other inflammatory processes (LI ranging from 0.5 per cent to 3 per cent). Most of the cells labelled from these CSF specimens were large lymphocytes, "lymphoid cells" and plasmacytes. Their presence in CSF is presumed to indicate an immune reaction. By the demonstration of a proliferative activity of these cells, aseptic inflammatory processes can be differentiated from "unspecific" pleocytosis. Because of a correlation between the LI of CSF cells and the stages of some inflammations, this method is suggested for an assessment of pregression or remission of chronic processes, e.g. "chronic meningitis" and multiple sclerosis. It can also be used in experimental research: the same type of mononuclear cells was labelled after having been cultured for 23 hours prior to the incubation with 3H-thymidine. Proliferating tumor cells as well as proliferating non-neoplastic mononuclear cells were demonstrated in CSF from various neoplastic diseases. In the clinical diagnosis of these processes, the method is of limited value. It proved very useful, however, for an assessment of the therapeutic effects of intrathecal cytostatic therapy. CSF specimens from non-inflammatory and non-neoplastic diseases regularly contained very few proliferating cells (LI: less than 0.1).