Purpose Here, we evaluate the sensitivity and specificity of a new 11-parameter flow cytometry (FCM) approach versus conventional cytology (CC) for detecting neoplastic cells in stabilized CSF samples from newly diagnosed aggressive B-cell non-Hodgkin's lymphoma (B-NHL) at high risk of CNS relapse, using a prospective, multicentric study design. Patients and Methods Moreover, we compared the distribution of different subpopulations of CSF leukocytes and the clinico-biologic characteristics of CSF+ versus CSF−, patients, in an attempt to define new algorithms useful for predicting CNS disease. Results Overall, 27 (22%) of 123 patients showed infiltration by FCM, while CC was positive in only seven patients (6%), with three other cases being suspicious (2%). CC+/FCM+ samples typically had more than 20% neoplastic B cells and/or ≥ one neoplastic B cell/μL, while FCM+/CC− samples showed lower levels (P < .0001) of infiltration. Interestingly, in Burkitt lymphoma, presence of CNS disease by FCM could be predicted with a high specificity when increased serum β2-microglobulin and neurological symptoms coexisted, while peripheral blood involvement was the only independent parameter associated with CNS disease in diffuse large B-cell lymphoma, with low predictive value. Conclusion FCM significantly improves the sensitivity of CC for the identification of leptomeningeal disease in aggressive B-NHL at higher risk of CNS disease, particularly in paucicellular samples.

Immunophenotypic characterization of B-cell chronic lymphoproliferative disorders (B-CLPD) is becoming increasingly complex due to usage of progressively larger panels of reagents and a high number of World Health Organization (WHO) entities. Typically, data analysis is performed separately for each stained aliquot of a sample; subsequently, an expert interprets the overall immunophenotypic profile (IP) of neoplastic B-cells and assigns it to specific diagnostic categories. We constructed a principal component analysis (PCA)-based tool to guide immunophenotypic classification of B-CLPD. Three reference groups of immunophenotypic data files—B-cell chronic lymphocytic leukemias (B-CLL; n=10), mantle cell (MCL; n=10) and follicular lymphomas (FL; n=10)—were built. Subsequently, each of the 175 cases studied was evaluated and assigned to either one of the three reference groups or to none of them (other B-CLPD). Most cases (89%) were correctly assigned to their corresponding WHO diagnostic group with overall positive and negative predictive values of 89 and 96%, respectively. The efficiency of the PCA-based approach was particularly high among typical B-CLL, MCL and FL vs other B-CLPD cases. In summary, PCA-guided immunophenotypic classification of B-CLPD is a promising tool for standardized interpretation of tumor IP, their classification into well-defined entities and comprehensive evaluation of antibody panels.

Leptomeningeal disease is an important adverse complication occurring in patients with B and T cell lymphomas and acute leukemias of lymphoid and myeloid origin. Recent reports suggest that multiparameter flow cytometry immunophenotypic assessment of spinal fluid samples could improve the efficiency of detection of CNS involvement, due to its high specificity and greater sensitivity. However, spinal fluid samples are frequently paucicellular with a rapidly decreasing cell viability. Staining of spinal fluid therefore requires dedicated sample storage/transport, staining, and preparation protocols. The Basic Protocol in this unit outlines a consensus multiparameter (3‐ to 8‐color) flow cytometry immunophenotypic protocol for the evaluation of CNS involvement of cerebrospinal fluid (CSF) samples by neoplastic cells. A Support Protocol describing the simultaneous assessment of surface and cytoplasmic antigens is also provided. Finally, in the Alternate Protocol, we describe a method to calculate absolute numbers of both normal and pathological cell subpopulations by adding counting beads to the assay. Curr. Protocol. Cytom. 45:6.25.1‐6.25.16. © 2008 by John Wiley & Sons, Inc.

B‐cell chronic lymphocytic leukemia (B‐CLL) is a well‐defined clinical entity with heterogeneous molecular and cytogenetic features. Here, we analyze the impact of trisomy 12, del(13q), del(17p), and del(11q) as determined by interphase fluorescence in situ hybridization analysis of purified neoplastic B‐CLL cells on their immunophenotype, DNA ploidy status and proliferative rate.Overall, 111 of 180 (62%) B‐CLL cases studied displayed one (50%) or more (12%) genetic abnormalities, del(13q) (35%) being more frequently detected than trisomy 12 (23%) followed by del(11q) (9%) and del(17p) (8%). Trisomy 12 was associated with a higher frequency of DNA aneuploidy, stronger expression of CD19, CD20, CD22, CD24, CD27, CD79b, CD38, and sIg and lower reactivity for CD43 with respect to cytogenetically nonaltered cases. In turn, cases with del(13q) displayed greater reactivity for CD20, FMC7, CD27, CD22, CD5, and bcl2, while del(11q) was associated with brighter expression of CD38, FMC7, CD25, and sIg. Hierarchical clustering analysis of the immunophenotype of B‐CLL cases with cytogenetic abnormalities allowed the identification of three different groups of patients with increasing frequencies of trisomy 12, del(11q), and del(13q). Remarkably, none of the cytogenetic abnormalities analyzed except coexistence of 13q‐ and 17p‐ had a clear impact on the proliferative index of B‐CLL cells. © 2007 Clinical Cytometry Society