Cerebrospinal fluid beta-2-microglobulin in adult patients with acute leukemia or lymphoma: a useful marker in early diagnosis and monitoring of CNS-involvement.

Beta-2-microglobulin (B2m) was measured in the cerebrospinal fluid (CSF) and serum from 18 adults with acute lymphoblastic leukemia, acute myeloblastic leukemia or lymphoma in order to detect early central nervous system (CNS) involvement or relapse. Six had CNS-involvement documented by neurologic symptoms and tumor cells in the CSF. Their CSF-B2m-concentrations were significantly higher before intrathecal chemotherapy than in those without this complication (P less than 0.01). During therapy CSF-B2m levels fell rapidly to normal values on repeated measurements. The study demonstrates that serial determination of CSF-B2m alone may be a useful and sensitive marker of CNS-dissemination in acute leukemia and malignant lymphoma. Using the criteria of CSF-B2m greater than 160 nmol/l as a positive diagnostic test the sensitivity of the test was 100%, the specificity was 76%. The same values for the CSF/serum-ratio greater than 1 were 75% and 64%, respectively.