Issue Highlights – March 2021

This issue of the journal focuses on flow cytometric detection Sézary syndrome (SS) and mycosis fungoides (MF) in peripheral blood (PB). As outlined editorial (Craig, 2021), cytometry has been used since early 1980's to immunophenotype SS MF, characteristic CD7-negative, CD26-negative was readily adopted by dermatology groups. However, there is frustration among both clinicians cytometrists. second article this series perspective (Guitart, dermatologists oncologists are frustrated variability practice reports, which often lack mention whether an abnormal population present, if phenotype compatible with SS/MF, quantity cells. There also labs, who recognize limitations using individual evaluations for CD7 CD26 use a different multi-parameter immunophenotyping approach evaluate other hematologic malignancies. An international group cytometrists convened address these frustrations, their work three articles issue. The Pulitzer, Horna, & Almeida provides detailed review including definitions major categories cutaneous T-cell lymphoma, diagnosis MF skin PB, role immunophenotyping. Horna colleagues (2021) builds information outline characteristics necessary assay designed PB approach. includes consideration antigens evaluate, strategy analysis, discussion about quantitation populations, reporting, illustrated supplemental examples. prompted letter editor from Roelens et al. describing favorable experience evaluation CD158k MF. reply (Almeida, Norna, authors highlight that others have not reported same success approach, caution antibody recommended available commercially as flow-cytometry reagent. next (Illingworth, al., describes how develop characteristics, instrument set-up, reagent selection assessment staining, validation optimized (including example template), ongoing monitors quality. should help laboratories every step introducing optimal PB. guidelines areas where remaining gaps our knowledge invite further investigation. such provided final issue, Lyapichev report direct comparison aberrancies versus quantification CD26− or CD7− CD4+ T-cells SS/MF patients, confirm former method (recommended group) more accurate staging, particularly patients low stage disease (B0 B1). Hopefully will prompt investigation, decrease widespread experienced