[Flow cytometry increases the proportion of valuable samples in cerebrospinal fluid with normal cell count in malignant blood diseases]. / La citometría de flujo aumenta la proporción de muestras valorables en líquido cefalorraquídeo con recuento celular normal en hemopatías malignas.

ABSTRACT

BACKGROUND: The alteration of cerebrospinal fluid (CSF) in hematologic neoplasms is a poor prognostic marker. The characteristics of CSF are usually analyzed by flow cytometry or cytology. However, paucicellular CSF samples (≤5 cells/dL) can sometimes be considered unsuitable for analysis due to the low number of events. OBJECTIVE: To evaluate the proportion of samples reported as suitable for analysis obtained by cytometry (FCM) and cytology in paucicellular CSF samples. MATERIAL AND METHODS: 169 samples ofpaucicellular CSF corresponding to 115 patients with hematologic neoplasms were selected. The samples were obtained by lumbar puncture in tubes conditioned with EDTA and Transfix®. We characterized the immunophenotype ofCSF samples with an 8-color panel, and 55 samples (32%) were in a small sample tube (SST). In all cases, monocytes were identified by CD14 labeling and T lymphocytes by CD3 labeling. The acquisition was carried out in a FACSCantoII® cytometer, and the analysis was performed using Infinicyt® software. RESULTS: The proportion of samples suitable for analysis was higher in FCM compared to cytology (98% vs 61%, p < 0.000). We identified the presence of T lymphocytes and/or monocytes in most samples (98% and 90%, respectively). In the SST samples, the number of events recorded in low-volume samples (< 1 mL) was lower than in samples with higher volume (140 vs 556, p < 0.001), with a median of identification of 3 cell populations. CONCLUSION: FCM allows the analysis of a higher proportion ofpaucicellular CSF samples than cytology in hematologic neoplasms study.