ESCCA/ISCCA protocol for the analysis of cerebrospinal fluid by multiparametric flow‐cytometry in hematological malignancies

Abstract

Central nervous system (CNS) involvement is a serious but often underdiagnosed complication of hematological malignancies. Currently, the gold standard to detect CNS involvement is conventional cytology (CC) whose sensitivity though is lower than 50%. Multiparametric flow cytometry (MFC) demonstrated a superior sensitivity over CC, particularly when low levels of CNS infiltrating cells are present. Although prospective studies are few, a positive finding by MFC appears to anticipate an adverse outcome even if CC shows no infiltration. However, the use of MFC to diagnose CNS involvement presents some pitfalls, due to the typical hypocellularity of cerebrospinal fluids (CSF), and low cell vitality. Furthermore, the threshold to be used for defining the MFC positivity is not universally defined. In this paper, a working group of the European Society for Clinical Cell Analysis-ESCCA-and the Italian Society for Clinical Cell Analysis-ISCCA-will discuss the critical aspects of CSF processing, highlighting difficulties in storage and processing of samples, interpretation and reporting of data.

Central nervous system (CNS) involvement has an adverse impact on survival in newly diagnosed adult acute lymphoblastic leukemia (ALL) assessed by flow cytometry

“…This has been described not only in patients with acute lymphoblastic leukemia but also in patients with other hematological malignancies. In a few reports that analyzed patients with non-Hodgkin lymphoma, leptomeningeal involvement was detected by cytometry in 22% of cases as opposed to 8% that were detected by cytology [8,[24][25][26][27][28][29], which strongly correlates with our results. Mitri et al [21] found that flow cytometry reached a sensitivity and specificity of 100% in the detection of leukemic blasts in the leptomeningeal space.…”

Value of cerebrospinal fluid white cell count and protein level in predicting leptomeningeal involvement by systemic aggressive B‐cell lymphoma

“…Samples with MFC deemed suspicious or positive by the reporting haematologist were included as positive, independent of number of abnormal events seen. This approach aligns with recent guidelines, 17 placing emphasis on the pattern of the abnormal events observed, rather than historical abnormal event number cut-offs.…”

Detection of CAR‐T19 cells in peripheral blood and cerebrospinal fluid: An assay applicable to routine diagnostic laboratories

“…CSF samples deteriorate rapidly, and recent guidelines recommend flow cytometry analysis within 1 h of lumbar puncture (Del Principe et al, 2020), which is not always possible. Preserving the CSF samples in transfix™ allows for flow cytometry analysis at a later time point and generally works well, although fixation can sometimes reduce the signal/noise ratio for some antigens and/or antibodies (De Jongste et al, 2014;Del Principe et al, 2020;Johansson et al, 2014). Here, we show that the sCD19F assay works well to detect CAR-T19 cells in fresh, but not transfixed™, CSF samples.…”