Unreliability of beta-2-microglobulin in early detection of central nervous system relapse in acute lymphoblastic...

The value of serial determination of the cerebrospinal fluid (CSF) beta-2-microglobulin (Beta 2m) level for early detection of acute lymphoblastic leukemia (ALL) in the central nervous system (CNS) has been prospectively studied in 30 children. Beta 2m was determined by micro-ELISA assay. Results demonstrated a sensitivity of 40% (95% confidence interval, 5.3-85.3%) and a predictive value of 8% (95% confidence interval, 1.0-26.0%). In post-irradiation syndrome, as well as in viral infection with cytopathological changes of white cells in CSF, beta 2m values proved to be significantly higher than in incipient CNS relapse, and these conditions, or an unknown cause, are more often associated with beta 2m elevation than CNS relapse. No relation was found between CSF white cell counts and beta 2m levels. It is concluded that beta 2m is not an appropriate test for early detection of CNS involvement in children with acute lymphoblastic leukemia.