Clinical significance of monoclonal B cells in cerebrospinal fluid

Flow cytometric characterization of cerebrospinal fluid cells

“…It has grave prognostic significance and requires important therapeutic decisions including the administration of intrathecal chemotherapy (6,46). Leptomeningeal localization is diagnosed by conventional cytomorphological analysis through identification of malignant lymphocytes in CSF (31,52). However, this technique has a relatively high rate of false-negative results in up to 60% of cases (22,53).…”

“…However, this technique has a relatively high rate of false-negative results in up to 60% of cases (22,53). Recent reports suggest that multiparameter flow cytometric assessment of CSF samples could improve the efficiency of detection of CNS involvement, due to its high specificity and greater sensitivity (6,52,54). Table 2 gives an overview of studies, which investigated the value of flow cytometry and conventional cytomorphology in detection of CSF involvement in hematological malignancies.…”

“…Blymphocyte clonality can be investigated by flow cytometry by assessing surface immunoglobulin light chain expression on CD19 þ B-lymphocytes and comparison of the ''light chain ratio (LCR)'' or ''kappa/lambda ratio,'' which is determined by dividing the percentage of cells with the dominant light chain by the percentage of cells with the minor light chain (52). Normal ranges for the LCR differ between laboratories.…”

“…Another important point of attention is that not every monoclonal B-cell population in CSF indicates symptomatic CNS disease (42). In patients with indolent hematological disorders, including chronic lymphatic leukemia, malignant B cells in the CSF may represent asymptomatic leptomeningeal involvement and may require treatment only when (new) symptoms arise (52,105,106). At last, clinical follow-up will aid in diagnosing CNS disease.…”

Detection of B‐cell populations with monotypic light chain expression in cerebrospinal fluid specimens from patients with multiple sclerosis by polychromatic flow cytometry

“…In such patients, the detection of a monoclonal B-cell population by flow cytometry might be interpreted as evidence for a B-cell lymphoproliferative disorder. Although the detection of monoclonal B-cell populations by flow cytometry in CSF from patients without lymphoma has been reported in rare cases (9), the specificity of flow cytometric immunophenotyping in the identification of monoclonal B-cell populations in CSF has not been systematically evaluated. We report here three cases in which monotypic immunoglobulin light chain-expressing B-cell populations were detected by polychromatic flow cytometry in CSF from patients without lymphoma, each of whom was ultimately diagnosed with multiple sclerosis upon complete clinical evaluation.…”