Flow cytometry in hematological nonmalignant disorders

Detection of Nonhematologic Neoplasms in Bone Marrow by Flow Cytometry: A Report of Two Cases

Multiparameter flow cytometry (MFC) is a well-established method for the diagnosis, prognosis, and follow-up of a vast majority of hematological malignancies; however, it can have a major impact on the rapid diagnosis of nonhematopoietic tumor micrometastases in minimally invasive samples such as bone marrow aspirates (BMAs), body fluids, and tissue samples (lymph nodes, fine needle aspirates). Here, we present two cases of bone marrow micrometastases of neuroendocrine origin (one small cell lung carcinoma [SCLC] and one large cell neuroendocrine carcinoma [LCNEC] of the lungs) readily recognized by routine MFC investigation of BMA and review the existing literature on the role of MFC in the diagnosis of solid tumors of neuroendocrine origin. The clinical application of flow cytometry for the diagnosis of solid tumors is limited despite the accumulating evidence of the value of the method. It can be of great value in situations where the patient's clinical status forbids invasive procedures, and a rapid diagnosis is desirable. Flow cytometry is a valuable tool for the detection of both hematological and nonhematologic neoplasms. Future large-scale patient series will probably confirm its role in the screening, diagnosis, and classification of more tumor types.

Routine flow cytometry approach for the evaluation of solid tumor neoplasms and immune cells in minimally invasive samples

BACKGROUND

Multidimensional flow cytometry (MFC) is routinely used for the diagnosis and follow-up of hematolymphoid neoplasms but its contribution to the identification of non-hematolymphoid malignant tumors is limited.

METHODS

The presence of non-hematolymphoid cells in clinical samples obtained via minimally invasive methods was ascertained by using a panel of monoclonal antibodies previously developed in our laboratory comprising a mixture of antibodies: CD9-PacB/CD45-OC515/CD57-FITC/CD56-PE/CD3-PerCP-Cy5.5/CD117-PE-Cy7/CD326-APC/CD81-APC-C750. Histopathological studies were performed using standard techniques.

RESULTS

164 specimens of different origins were included. Malignancy was finally confirmed in 142 (86.5%), while 22 non neoplastic samples were identified. The most frequent diagnosis was small cell lung carcinoma (SCLC) (50%). High sensitivity (S = 98.6%) was reached combining MFC and conventional pathology. Individual markers differed according to the cellular origin of the neoplasm, with neuroendocrine tumors showing a unique immunophenotypic profile (CD56+ CD326+ CD117-/+ and variable tetraspanins expression). Principal component analysis efficiently distinguished SCLC from other tumor samples. In immune cell populations, differences between reactive and malignant biopsies were found in different cell compartments, especially in B cells and Plasma cells. Differences also emerged in the percentage of CD4+ CD8- T cells, CD4-CD8+ T cells and NK cells and these were dependent on the origin of the tumor cells.

CONCLUSIONS

These results support the use of MFC as a rapid and valuable technique to detect non-hematolymphoid tumoral cells in clinical specimens, providing an initial orientation to complement hystopathological studies and allow a more precise diagnosis, especially in neuroendocrine neoplasms. The impact of different immune cell patterns warrants further research.

Development of an algorithm for the identification of leukemic hematolymphoid neoplasms in Primary Care patients

BACKGROUND

Diagnosis of hematolymphoid neoplasm (HLN) requires different technologies which are performed on a patient basis instead of per protocol. We hypothesize that integration of hematimetric and cytological analysis along with multiparametric flow cytometry (MFC) provides a framework to evaluate peripheral blood (PB) samples from Primary Care.

METHODS

Samples from patients with persistent (>3 months) lymphocytosis (>5 × 109/L) and/or monocytosis (>109/L) or the presence of atypical and/or blast cells upon the smear review were analyzed by MFC concurrent to cytological analysis. MFC studies were carried out following standardized procedures.

RESULTS

In a 3-year period, smear review and MFC were performed simultaneously in 350 samples, demonstrating HLN in 194 cases (55.4%). In 156 cases, reactive cell populations were found. The combination of age, absolute lymphocyte count (ALC), hemoglobin and platelets provided the best correlation with MFC for the presence of a chronic lymphoproliferative disorder (CLPD) in lymphocytosis [area under the curve (AUC) 0.891, p < 0.05]. A model evaluating the probability of CLPD has been proposed and validated in an independent cohort.

CONCLUSIONS

A strategy to perform MFC studies following standardized procedures has proven to be useful to evaluate samples from patients in Primary Care centers for HLN diagnosis or reactive conditions, providing a sensitive and rapid clinical orientation and avoiding unnecessary consultations in routine clinical practice. The probability for the presence of CLPD in PB can be calculated and help guide decision-making regarding further testing.

Evaluation of a 10color protocol as part of a 2tube screening panel for flow cytometric assessment of peripheral blood leukocytic subsets

Peripheral blood (PB) immunophenotyping is commonly required for initial evaluation of various suspected disease entities. Several approaches have been proposed. The objective of this work is to explore the value of a 10color protocol developed in our laboratory for flow cytometric assessment of PB leukocytic subsets, as part of a 2tube screening panel. A combination of CD16/CD56/CD34/CD33/CD19/CD4/CD8/CD3/CD20/CD45 antibodies in 1 tube was applied routinely during flow cytometric analysis of PB samples for diagnostic purposes. The protocol was systematically complemented by a 2nd tube with anti-kappa, anti-lambda, CD5, CD19, and CD45 antibodies for adults and selected pediatric patients, and specifically oriented panels when necessary. 25 samples with no detectable neoplastic PB involvement and 31 samples with a hematolymphoid disorder were investigated retrospectively. The contribution of CD33 in the separation of leukocytic populations, as well as the benefits from the simultaneous assessment of CD20/CD19/CD45, CD16/CD56 and the detection of CD34+ cells were examined. The gating strategy with the use of CD33 provided additional information in certain cases. The protocol enabled recognition of differential expression of CD20 and CD45 in CD19+ cells with chronic lymphocytic leukemia phenotype, overall evaluation of NK and NK like T cells, estimation of CD16- granulocytes and CD56/CD16 expression in monocytes, as well as identification of minor cell subsets, such as CD34+ cells. The proposed 10color combination of antibodies analyzed in a standardized manner can offer significant information in the initial evaluation of PB samples, thus, guiding subsequent investigation if needed.

ICCS/ESCCA consensus guidelines to detect GPI-deficient cells in paroxysmal nocturnal hemoglobinuria (PNH) and related disorders part 4 - assay validation and quality assurance

Over the past six years, a diverse group of stakeholders have put forth recommendations regarding the analytical validation of flow cytometric methods and described in detail the differences between cell-based and traditional soluble analyte assay validations. This manuscript is based on these general recommendations as well as the published experience of experts in the area of PNH testing. The goal is to provide practical assay-specific guidelines for the validation of high-sensitivity flow cytometric PNH assays. Examples of the reports and validation data described herein are provided in Supporting Information. © 2017 International Clinical Cytometry Society.

A standardized immune phenotyping and automated data analysis platform for multicenter biomarker studies

The analysis and validation of flow cytometry-based biomarkers in clinical studies are limited by the lack of standardized protocols that are reproducible across multiple centers and suitable for use with either unfractionated blood or cryopreserved PBMCs. Here we report the development of a platform that standardizes a set of flow cytometry panels across multiple centers, with high reproducibility in blood or PBMCs from either healthy subjects or patients 100 days after hematopoietic stem cell transplantation. Inter-center comparisons of replicate samples showed low variation, with interindividual variation exceeding inter-center variation for most populations (coefficients of variability <20% and interclass correlation coefficients >0.75). Exceptions included low-abundance populations defined by markers with indistinct expression boundaries (e.g., plasmablasts, monocyte subsets) or populations defined by markers sensitive to cryopreservation, such as CD62L and CD45RA. Automated gating pipelines were developed and validated on an independent data set, revealing high Spearman's correlations (rs >0.9) with manual analyses. This workflow, which includes pre-formatted antibody cocktails, standardized protocols for acquisition, and validated automated analysis pipelines, can be readily implemented in multicenter clinical trials. This approach facilitates the collection of robust immune phenotyping data and comparison of data from independent studies.

The prognostic value of multiparametric flow cytometry in AL amyloidosis at diagnosis and at the end of first-line treatment

Multiparametric flow cytometry (MFC) in amyloid light-chain (AL) amyloidosis has not been widely adopted and, consequently, there is little information on its clinical relevance. We studied 173 patients with AL amyloidosis who underwent MFC immunophenotyping of bone marrow sample at diagnosis and 82 patients at the end of the first line of treatment (EOT). The number of monotypic plasma cells (PCs) and the polytypic PCs/bone marrow PCs (pPCs/BMPCs) ratio were analyzed. At diagnosis, ≥2.5% monotypic PCs was associated with a shorter progression-free survival (PFS) and overall survival (OS) compared with patients with <2.5% monotypic PCs (2-year PFS 41% vs 56%, P = .007; 2-year OS 55% vs 70%; P = .01). Additionally, patients with a pPCs/BMPCs ratio of ≤5% had a shorter PFS compared with patients with pPCs/BMPCs ratio >5% (2-year PFS 43% vs 55%; P = .02), but without OS difference (2-year OS 60% vs 67%; P = .19). In a multivariate analysis, the monotypic PCs retained an independent prediction for PFS/OS, whereas the pPCs/BMPCs ratio retained significance only for PFS. At EOT, ≥0.1% monotypic PCs was associated with a shorter PFS and OS compared with patients with <0.1% monotypic PCs (2-year PFS 31% vs 87%; P < .0001; 2-year OS 87% vs 98%, P = .02). In a subgroup analysis among patients who attained a very good partial response or better, the monotypic PCs at the 0.1% cutoff was predictive for progression rate but not for PFS/OS. MFC is prognostic for AL amyloidosis at diagnosis and at EOT. MFC may have a role in the definition of hematologic response.