CSF Beta₂-Microglobulin in Diagnosis of CNS Leukemia or Lymphoma

To the Editor: We read with interest the recent paper by Mavligit et al. in the September 25 issue. However, we would like to ask the following questions: How many patients were included in the analysis simply because of an elevation of cerebrospinal fluid (CSF) protein that was compatible with neurologic symptoms and signs? Would the P values for differences between the two groups of patients have reached a significant level if the analysis had considered only patients in whom Central-nervous-system (CNS) lymphoma or leukemia had been diagnosed through cytology of the CSF, brain biopsy, or post-mortem examination? The elevation.