Diagnosis of meningeal leukemia using immunoperoxidase methods to demonstrate common acute lymphoblastic leukemia cells in cerebrospinal fluid.

The immunological phenotype of cells in the cerebrospinal fluid (CSF) was determined with immunoperoxidase techniques. A medium was used which allowed cells to stand at room temperature for 24 h without appreciable loss of cells. From 62 patients a total number of 208 CSF specimens were analysed. It proved possible to perform 4 determinations and a control reaction on 2.5 ml of CSF: cell count, cytology, E-rosetting and staining with a monoclonal antibody, provided that more than 1 cell per mm3 were present. This study focussed on the presence of the common acute lymphoblastic leukemia marker (cALL, determined with the monoclonal antibody J5). All 21 CSF specimens containing more than 5% cALL positive cells were from patients with an initial diagnosis of common ALL, 8 of these samples were considered to be normal and 3 uncertain by standard cytological criteria. Six of the 8 samples which were cytologically normal, were from patients who had clear meningeal involvement at diagnosis, or developed a relapse later. There were no patients who developed a meningeal relapse on cytological criteria that was not detected by immunocytology. In one patient a cytological diagnosis of meningeal relapse was not confirmed by immunocytology, this patient is disease free 2 yr later without cytostatic treatment. Immunoperoxidase methods to detect cALL positive cells in CSF are an invaluable aid to the diagnosis of meningeal leukemia.