title: Measurement of lymphocyte aggregation by flow cytometry-physiological implications in chronic lymphocytic leukemia.
abstract: Cellular aggregation is a physiological response of lymphocytes to various extracellular stimuli. Currently, lymphocytes aggregation is only evaluated qualitatively or by semiquantitative methods. In this study, we assessed the capacity of flow cytometry to measure lymphocytes aggregation in a quantitative, accurate, and reproducible manner, and examined the significance of aggregation responses in various lymphoproliferative diseases.
  
  
  
  Extracellular triggers such as anti-CD19 antibodies or phorbol ester were utilized to induce lymphoid cells aggregation in a concentration dependent manner. Aggregation was quantified by flow cytometry based on the forward or side scatter (SSC), or by dark-field SSC of aggregates measured by ImageStreamX. Accuracy, reproducibility, and limitations of the methodology were evaluated. Aggregation responses were measured in various types of lymphoproliferative diseases, and correlated with immunophenotyping and IGHV mutational status in chronic lymphocytic leukemia.
  
  
  
  Lymphoid aggregates provoked by extracellular stimuli elevate the forward and SSC signals relatively to the number of cells in each event. Aggregation responses vary among different types of lymphoproliferative diseases. Moreover, elevated levels of CD19-induced aggregation are associated with aberrant chronic lymphocytic leukemia characteristics, but not with IGHV mutational status of the disease
  
  
  
  We have demonstrated that flow cytometry can provide accurate and reproducible measurement of both primary as well as T and B cell lines aggregation in response to extracellular stimuli. The use of quantitative evaluation of activation driven or other cellular aggregation may provide an analytical tool to elucidate biochemical and molecular mechanisms associated with lymphoproliferative diseases. © 2015 International Clinical Cytometry Society.
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.|Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel.
authors.forename: Nili
authors.initials: N
authors.lastname: Dezorella
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.
authors.forename: Sigi
authors.initials: S
authors.lastname: Kay
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.
authors.forename: Shoshana
authors.initials: S
authors.lastname: Baron
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.
authors.forename: Mika
authors.initials: M
authors.lastname: Shapiro
authors.affiliation: The Biological Services Department, Life Sciences Faculty, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Ziv
authors.initials: Z
authors.lastname: Porat
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.
authors.forename: Varda
authors.initials: V
authors.lastname: Deutsch
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.|Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel.
authors.forename: Yair
authors.initials: Y
authors.lastname: Herishanu
authors.affiliation: The Department of Hematology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel, 64239.|Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel.
authors.forename: Ben-Zion
authors.initials: BZ
authors.lastname: Katz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis* / Q000276:immunology; D008232:Lymphoproliferative Disorders / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D008875:Middle Aged; D015203:Reproducibility of Results
chemical_list: D015703:Antigens, CD
keywords: CD19; aggregation; chronic lymphocytic leukemia; flow cytometry; lymphocytes; side scatter