ELEVATION OF CEREBROSPINAL-FLUID SOLUBLE CD27 LEVELS IN PATIENTS WITHMENINGEAL LOCALIZATION OF LYMPHOID MALIGNANCIES

Diagnosis of meningeal localization of lymphoid malignancies by means of cytologic examination of the cerebrospinal fluid (CSF) can be diffi cult. Thus far no reliable CSF tumor markers have been identified. CD2 7 is a transmembrane disulfide-linked 55-kD homodimer present on most peripheral blood T cells and on a subset of B cells. CD27 is also expr essed on human malignant B cells and high levels of soluble CD27 can b e present in the serum of patients with B-cell malignancies. The aim o f this study is to determine prospectively the diagnostic value of CSF sCD27 as a tumor marker in patients with meningeal localization of ly mphoid malignancies. CSF sCD27 levels were determined by sandwich enzy me-linked immunosorbent assay. The optimal cut-off value using receive r operator characteristics curves was found to be 10 U/mL. sCD27 level s were normal in all 50 control patients (lumbar disc protrusion) and in 39 of 40 samples obtained from patients with either solid tumors or acute myeloid leukemia. Of 104 CSF samples from 70 children with acut e lymphoblastic leukemia (ALL) or non-Hodgkin's lymphoma (NHL) undergo ing routine central nervous system (CNS) staging, sCD27 was false posi tive and false negative in only one sample each. In 70 samples from 45 patients suspected of meningeal localization of ALL or NHL, the sCD27 test had an excellent sensitivity (100%) and specificity (82%). In 7 patients with positive CSF studied longitudinally, sCD27 levels correl ated very well with remission and relapse. sCD27 levels were not nonsp ecifically increased by the administration of cytostatic drugs. Finall y. sCD27 was also elevated in the 4 patients studied with primary cent ral nervous system lymphoma (PCNSL). CSF sCD27 is a promising tumor ma rker in patients with either meningeal localization of lymphoid malign ancies or PCNSL, and can be useful in the differential diagnosis of CN S involvement by either lymphoid malignancies or solid tumors. (C) 199 6 by The American Society of Hematology.