FlowCytoNews
Flow cytometry, gated weekly.
ISSUE #4 · MONDAY EDITION · THE LITERATURE · OCT 12, 2026
Welcome to the Monday edition of FlowCytoNews. Monday is The Literature: the cytometry papers and preprints that went online in the last two weeks, who did the work, and the number that matters from each abstract. Wednesday brings On the Calendar and Friday brings Industry Moves. This fortnight: flow MRD as an early endpoint in 2,623 AML patients, a synthetic control for myeloma trial assays, and why a third of DLBCL biopsies come back flow-negative. Tell us what we missed — hit reply.
■ The Literature
No new OMIP appeared in Cytometry Part A this fortnight, and Cytometry Part B has not yet published the first panel in its clinical series.
In 2,623 AML patients, flow MRD negativity tracked survival patient by patient
Bruno Paiva (Clínica Universidad de Navarra, Pamplona) and Pau Montesinos (Hospital La Fe, Valencia) for the PETHEMA group analyzed flow cytometry MRD in 2,623 patients with AML treated with intensive therapy. "MRD was detected in 68% of patients and presence of MRD levels ≥0.01-<0.1% associated with inferior OS." MRD-negative complete remission at the 0.01% cutoff "showed independent prognostic value and was significantly correlated with OS at the individual patient-level (Global odds ratio 1.23; 95% CI, 1.02-1.40)." The caveat is in the abstract too: "significance was lost in specific subgroups defined by genetic risk and post-consolidation treatment." No industry co-authors.
▪ Leukemia · Oct 8 · 10.1038/s41375-026-03153-4
Why it matters: The case for MRD as an early endpoint rests on it predicting survival for the individual patient, not just across groups. This is that analysis for flow at 0.01%. It also says 0.01–0.1% is not a safe zone, so do not report low-positive results as "negative".
An engineered myeloma control replaced the MM.1S cell line in BCMA and GPRC5D trial assays
Dhong Hyun Lee and Justine Dell'Aringa (Bristol Myers Squibb, Seattle) and six co-authors from Slingshot Biosciences (Emeryville, CA) evaluated a synthetic cell mimic built with Slingshot's TruCytes technology as an assay control for myeloma flow panels. The usual control falls short: "Although MM.1S shows strong expression of the key markers BCMA and GPRC5D, it lacks CD45 and CD19 which are needed for PC and B cell identification." The mimic carries separate plasma-cell and B-cell populations. "Qualification studies demonstrated intra- and inter-assay precision (%CV ≤20%), robust inter-instrument reproducibility, post-reconstitution stability up to 7 days at 4°C, and closed-vial storage stability of up to 13 months at -20°C." All ten authors are from the two companies.
▪ Cytometry Part B · Oct 5 · 10.1002/cyto.b.70075
Why it matters: Trial assays for bispecifics and CAR-Ts that target BCMA and GPRC5D run for years across sites. A control has to gate like the patient sample and stay stable between lots; this paper sets out the qualification data a sponsor would ask for.
Nine labs, one protocol: what lymphocyte-subset precision looks like when it is harmonized
Lin Xiao and Wei Cui (Cancer Hospital, Chinese Academy of Medical Sciences, Beijing), with co-authors Xu Wu and Gong Cheng of BD Biosciences ("Department of BD Biosciences, Becton Dickinson and Company, Shanghai, China"), ran "205 whole blood samples and 54 quality control samples at two levels from nine clinical laboratories across five regions in China" on a single-platform protocol. "Intra-assay and inter-assay coefficients of variation were below 8% and 6% for RC, below 10% and 9% for AC, respectively." Stability: "Whole blood remained stable for 24 hours post-collection (RC bias <14%; AC bias ≤15%), and processed samples for 48 hours post-staining (RC bias <13%; AC bias <19%)."
▪ Translational Research · Oct 8 · 10.1016/j.trsl.2026.10.003
Why it matters: These are ready-made acceptance criteria for a T/B/NK verification, and the stability windows tell you how long a courier delay you can tolerate before absolute counts drift.
Flow found DLBCL in only two-thirds of biopsies, and viability explained much of the gap
Victor Pas, Mattias Hofmans and Stijn Lambrecht (Ghent University Hospital) reviewed 53 samples from patients diagnosed with diffuse large B-cell lymphoma. "Detection rate was found at 67.9%. Average viability was 57% when disease was detected on FCM, and 28% when it was not. Detection rate in lymphoid samples was 85%, and in non-lymphoid tissue 57%." Large cells also confuse the usual gates: side scatter was high in most cases, and "light chain restriction was not detected in 19%." No industry co-authors.
▪ Acta Clinica Belgica · Oct 7 · 10.1080/17843286.2026.2742317
Why it matters: A flow-negative tissue sample with poor viability is not a negative result. See Bench Notes for how to report it.
Flow showed BCMA and GPRC5D vary within the same patient, and a trispecific covered both
Chloe O'Neill and Niels van de Donk (Amsterdam UMC), with four Johnson & Johnson co-authors (Spring House, PA, and Beerse, Belgium; the study was J&J-funded), report that "Using flow cytometry, we found that BCMA and GPRC5D expression is highly heterogeneous within and between patients." The BCMA/GPRC5D trispecific antibody ramantamig "effectively induced MM cell lysis in 32 BM samples from MM patients (mean lysis with 0.4 nM: 60%), demonstrating superior cytotoxic activity compared to BCMA- and GPRC5D-mono-targeting BsAbs (13% and 5%, respectively)."
▪ HemaSphere · Oct 7 · 10.1002/hem3.70487
Why it matters: Antigen-loss relapse after BCMA or GPRC5D therapy is called by flow. Report target-antigen intensity per population, not only percent positive, because a dim subpopulation is the one that escapes.
Also out
Myeloma immune microenvironment by mass cytometry. Hongwei Tang and Linda Baughn (Mayo Clinic) profiled "128 bone marrow aspirates" by mass cytometry and scRNA-seq across plasma cell disorders in self-identified Black and other patients, validated in "286 patients with MM from the MMRF Immune Atlas." — Blood · Oct 5 · 10.1182/blood.2026033998
CD8 T cells in Hodgkin lymphoma shift after PD-1 blockade. Matthew Salaciak and Nathalie Johnson (McGill; Lady Davis Institute, Montreal) validated a shift from TCF1⁺ to CX3CR1⁺ "intermediately exhausted" CD8 T cells "by flow cytometry in 11 relapsed cHL patients (pre- and post anti-PD1) and 6 healthy age-matched controls." — Cancer Immunology Research · Sep 28 · 10.1158/2326-6066.CIR-26-0127
Flow MRD guided stopping therapy in CLL. Ahmad Alhuraiji (Kuwait Cancer Control Center) and Nitin Jain (MD Anderson) added venetoclax to BTK inhibitors in 8 patients with persistent flow MRD; "4 of 6 evaluable patients (66%) achieved undetectable MRD." — Leukemia & Lymphoma · Oct 1 · 10.1080/10428194.2026.2741763
A protocol set for CD8 exhaustion in LCMV. Dominique Stark and Annette Oxenius (ETH Zurich) cover virus prep, tetramers, adoptive transfer, high-parameter staining, restimulation and sorting, "to support harmonization and optimization of workflows." — Current Protocols · Sep 29 · 10.1002/cpz1.70445
Single-EV flow of amniotic fluid without ultracentrifugation. Rui Gan and Jiahui Guo (Jinan University, Guangzhou) use double size-exclusion chromatography; it "yielded significantly more particles than conventional UC, while maintaining a comparable level of purity." — Analytical Methods · Oct 1 · 10.1039/d6ay00963h
Counting gold nanoparticles per cell by CyTOF. Quy Van-Chanh Le and Ivan Kempson (Adelaide University) found a monocyte subpopulation with "almost 2 orders of magnitude greater association than NK cell median." — Analytical and Bioanalytical Chemistry · Sep 28 · 10.1007/s00216-026-06842-2
"Overall concordance may overstate peripheral blood MRD performance in AML remission." A letter from Ercan Yılmaz and Erdem Topal (Inonu University, Malatya). No abstract online, so title only. — Cytometry Part B · Oct 7 · 10.1002/cyto.b.70079
A 15-color spectral panel for human leukocytes. Sarah Fidai and Ankit Saxena (Rutgers), a chapter in the Immunophenotyping volume of Methods in Molecular Biology. — Methods Mol Biol · Oct 1 · 10.1007/978-1-0716-5607-5_19
Preprints
AML's expanded CD8 T cells look NK-like, not exhausted. Yunli Chu and P. Brent Ferrell (Vanderbilt) ran mass cytometry on "bone marrow samples from 46 newly diagnosed AML patients"; CD8 T cells "were skewed toward terminally differentiated effector memory cells re-expressing CD45RA (TEMRAs), while canonically exhausted T cell populations were rare." — bioRxiv · Oct 2 · 10.64898/2026.09.30.755147
Brain tissue for suspension mass cytometry: skip the Percoll. Caroline Roe and Andra Dingman (CU Anschutz), with Jonathan Irish: Percoll cleanup gave an "average decrease of 88%" in viable cells, while cryopreservation kept population proportions (grey matter "r = 0.95"). — bioRxiv · Sep 28 · 10.64898/2026.09.22.753505
Reading signaling state from Golgi shape by imaging flow. SIGMA, from Mengchen Fan and Pulin Che (UAB), "achieved 90.02% cell-level accuracy" across four signaling cascades in fibroblasts. — bioRxiv · Oct 2 · 10.64898/2026.10.01.756010
■ Bench Notes
Report a low-viability tissue as non-diagnostic, not negative
In the Ghent DLBCL series (10.1080/17843286.2026.2742317), average viability was 57% when flow found the lymphoma and 28% when it missed it. To keep a dead sample from becoming a false reassurance:
Put a viability dye in every tissue tube and gate on live cells before you look for a clone. Record the viable fraction in the report, not only in the worksheet.
Set a lab threshold for a non-diagnostic result. Below it, a negative becomes "insufficient viable cells for exclusion of lymphoma", with a comment recommending histology. Base the threshold on your own discordant cases.
Look outside the lymphocyte gate. Large-cell lymphomas sit at high side scatter; open a CD19 or CD20 versus side-scatter plot across the full scatter range before you call the B cells polytypic.
Do not rely on light chains alone. Restriction was absent in 19% of the Ghent cases; add an aberrancy screen (for example CD10, loss of CD20 intensity, or abnormal CD38) and correlate with morphology.
Watch the clock. For blood, the nine-lab study above found counts stable for 24 hours after collection and 48 hours after staining (10.1016/j.trsl.2026.10.003). For tissue, log receipt time and note any processing delay in the report.
What did we miss? Hit reply — corrections run at the top of the next edition. If a colleague signs out lymphoma or runs MRD, forward this to them.
— Josh