Shedding of CD9 antigen into cerebrospinal fluid by acute lymphoblastic
leukemia cells
Y Komada, H Ochiai, K Shimizu, E Azuma, H Kamiya and M Sakurai
Department of Pediatrics, Mie University School of Medicine, Japan.
The accurate identification of small numbers of leukemic cells in the
cerebrospinal fluid (CSF) presents a diagnostic problem in the treatment of
acute lymphoblastic leukemia (ALL). We demonstrated that soluble CD9
antigen was shed into CSF obtained from children with ALL, using
enzyme-linked immunosorbent assay (ELISA), which used the activity of CD9
antigen to bind the Ricinus communis agglutinin (RCA1) and a monoclonal
antibody, SJ-9A4, simultaneously. Using RCA1/SJ-9A4 ELISA, CD9 antigen was
detectable in CSF but not in plasma from 12 cases of CD9+ ALL in central
nervous system (CNS) relapse. However, CD9 antigen was not released into
CSF from 11 cases of CD9- ALL with CNS involvement, 136 cases of CD9+ ALL
in complete remission (CR), 29 cases of CD9- ALL in CR, or 21 cases of
aseptic meningitis. Interestingly, the levels of CD9 antigen were elevated
in CSF from 7 of 10 CD9+ ALL patients without cytologically proven CNS
involvement at diagnosis, with subsequent return to undetectable levels
after initial induction chemotherapy was begun. In addition, sequential
analysis of CSF from a 5-year-old boy with CD9+ ALL in CNS relapse showed
that levels of CD9 antigen correlated well with the number of leukemic
cells in CSF. Serial quantitative analysis of CD9 antigen in CSF could be
useful to detect the proliferation of residual leukemic cells before the
clinical manifestation.
Volume 76,
Issue 1,
pp. 112-116,
07/01/1990
Copyright © 1990 by The American Society of Hematology
