Identification of Reed-Berezovsky-Sternberg cells in lymphatic nodes in classic Hodgkin's lymphoma by flow cytometry: a clinical case series

Despite their B cell origin, Reed-Berezovsky-Sternberg tumor cells (RBS) in classic Hodgkin's lymphoma (cHL) demonstrate an absolutely unique phenotype. Immunohistochemistry of RBS cells is positive for CD15 antigen in most of cases, CD30, PAX-5; they do not express the T cell antigen CD3, В cell CD19, and in most cases are negative for the B cell antigen CD20, as well as for common leukocyte antigen CD45. Taking into account such unequivocal immunophenotype, RBS cells can be identified by multiparameter flow cytometry. Thus, J.R. Fromm et al. (2006, 2014) have convincingly shown the possibility to identify RBS cells in a puncture and/or biopsy sample of lymphatic nodes in cHL and were of the fair opinion that such rather simple and reproducible technique as flow cytometry could be an additional diagnostic instrument in cHL. We have tested the technique proposed by J.R. Fromm et al. for the assessment of lymphatic node involvement in cHL and used 8 to 10-parameter flow cytometry for detection RBS cells in cHL in 8 biopsy samples of a lymphatic node, and confirmed the feasibility to identify RBS cells by high performance flow cytometry. We also performed morphological and immunohistochemical assessment of the biopsy samples of lymphatic nodes from patients with suspected cHL. The study included clinical cases with immunohistochemically confirmed cHL (n = 8), and the control samples were from those with other diagnoses than Hodgkin's lymphoma. In all cases of cHL we found RBS cells. In future we plan to analyze larger case samples by flow cytometry.