DNA SINGLE-CELL CYTOMETRY IN LYMPHOCYTIC PLEOCYTOSIS OF THE CEREBROSPINAL-FLUID

The value of DNA single-cell cytometry for the detection of neoplasia in Feulgen-stained cerebrospinal fluid cytological specimens was teste d on 34 cases of Non-Hodgkin's lymphoma or leukemia and on 66 cases of viral or bacterial meningitis as a disease control group. The DNA con tent of 200 randomly chosen nuclei was measured on one pre-existing, c ytologically representative slide per case, using a TV-image analysis system TAS-plus (Leitz, Germany). Neoplasia was diagnosed, if at least three nuclei with a DNA content above 5c (5cEE greater-than-or-equal- to 3) were found. The sensitivity investigating only one slide per cas e was 79.4% (27/34), the specificity 78.8% (52/66). Three lymphomas an d 7 inflammatory cases were classified as suspicious (0 < 5cEE < 3). I n 4 lymphoma cases (11.8%) a false-negative diagnosis and in 7 cases ( 10.6%) of viral meningitis a false-positive diagnosis were made. No fa lse-positive diagnosis occurred in bacterial meningitis. While the fal se-negative diagnoses may be due to the only slightly increased number of cells in cerebrospinal fluid, no final explanation for increased D NA values after viral infection can be given. Therefore, before using DNA single-cell cytometry to proove the malignant character of lymphoc ytic pleocytosis in cerebrospinal fluid, viral meningitis has to be cl inically excluded.