EFB Dengue Literature Review

Atypical B Cell

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Atypical B Cell

Umbrella / hub page. This is the organizing entry point for the wiki’s central cell population — the atypical / age-associated B cell cluster and its sub-states. It maps the field’s overlapping labels onto the precise nomenclature and routes to the detailed pages; it does not restate their content. For the canonical sub-population pages see Double-Negative B Cell, DN2 B Cell, DN3 B Cell, and the EF precursor Activated Naive B Cell.

Overview

“Atypical B cells” (AtB), “age-associated B cells” (ABCs), “T-bet⁺ B cells,” “CD11c⁺ B cells,” and “double-negative (DN) B cells” are overlapping labels for a B cell cluster that expands outside the conventional naive→GC→memory axis — typically CD21⁻, often IgD⁻CD27⁻, T-bet⁺, CD11c⁺, FCRL5⁺ — and is generated substantially through the extrafollicular pathway. This cluster, together with the Plasmablast it can feed, is the cellular spine of the wiki: the compartment whose expansion is tracked across SLE, malaria, COVID-19, and dengue, and whose antibody output connects to the autoantibody and ADE questions (see the cross-wiki bridge in ../bridge-wiki/).

The labels are not synonyms for one cell. Sanz (2025) argues the “atypical B cell” term is actively misleading: cells thus labelled are a normal component of immune responses (not atypical), their nature/derivation/function depend on immunological context, and inconsistent marker schemes (CD27⁻, CD21lo, CD11c⁺, T-bet⁺, FcRL5⁺ — used alone or combined, often without IgD) conflate at least five distinct populations. This wiki therefore uses DN nomenclature as the precise classification and treats “atypical / age-associated B cell” as the field-level umbrella term, not a cell identity (see Sanz2025 - Human Atypical B Cells Overview, invited review).

Synonymy map (field term → precise population)

Field / umbrella termPrecise population (this wiki)Defining markers
“Atypical B cell” (AtB) — broadthe whole cluster belowcontext-dependent; ≥5 populations (Sanz2025)
Age-associated B cell (ABC) — heterogeneous supersetAge-Associated B Cell (CD27⁺ + IgD⁺ + predominantly IgD⁻CD27⁻); only its IgD⁻CD27⁻ subset maps to DN2T-bet⁺, CD11c⁺ (murine origin)
“DN / double-negative”Double-Negative B Cell (IgD⁻CD27⁻)IgD⁻CD27⁻; subdivided below
EF effector / pre-plasmablastDN2 B CellCXCR5⁻CD21⁻CD11c⁺CD19^hi, T-bet⁺, FCRL5⁺
pre-plasmablast (T-bet⁻)DN3 B CellCXCR5⁻CD21⁻CD11c⁻T-bet⁻
activated naive (EF precursor)Activated Naive B CellIgD⁺CD27⁻CD21⁻CD11c⁺CD24⁻
“alternative lineage” (atBC1–3, MBC1)transcriptomic superset of the aboveT-bet/CD11c/FCRL5; CD11c best single marker
HIV “tissue-like memory” (Moir et al.)maps onto this cluster (Cancro2020)CD21⁻CD27⁻; BCR-hyporesponsive, TLR9-responsive
Malaria “atypical memory” (Weiss et al. 2009)maps onto this cluster (Cancro2020)IFN-γ-driven; diverse V_H usage
VAT “inflammatory B cells” / “late memory B cells” (Frasca/Blomberg)maps onto this cluster (Cancro2020)T-bet⁺CD21⁻; rise with age; correlate with ABC numbers
⚠ “DN MBC” in the CD80/PD-L2 literatureNOT this cluster — see the false-friend note belowCD80⁻PD-L2⁻; an origin proxy, not an atypical marker

⚠ False friend — two unrelated “DN”s. A large murine memory literature (Shlomchik lab and the GC-fate-mapping field) subsets MBCs on CD80 and PD-L2 into DP (CD80⁺PD-L2⁺), SP (CD80⁻PD-L2⁺), and DN (CD80⁻PD-L2⁻). In that scheme DP is enriched for GC-derived MBCs and “DN” consists almost exclusively of GC-independent early MBCs — the label is a proxy for developmental origin, and has nothing to do with IgD or CD27 (see Glaros2025 - Multilayered Identity of B Cell Memory, review). This wiki’s Double-Negative B Cell means IgD⁻CD27⁻. The two axes are independent and the collision is a live misreading hazard when importing murine memory papers: a “DN MBC” in that literature is a quiescent, low-SHM, largely unswitched cell, roughly the opposite of the activated CD21⁻CD11c⁺ effector this wiki tracks.

Key Points from Literature

  • The label conflates ≥5 populations; context determines identity. Naïve-derived EF effectors (aNAV/DN2), resting CD27⁻ memory (DN1), pre-plasmablasts (DN3), CD11c⁺ switched-memory ABC, and tissue-resident FcRL4⁺ cells have all been called “atypical.” Phenotype does not fix function across diseases (see Sanz2025 - Human Atypical B Cells Overview, review).

  • Abundant at baseline, not a pathology-only population. Transcriptomically defined “alternative lineage” B cells are ~20% of B cells in healthy non-exposed donors — far above the ~5% DN frequency reported by flow cytometry, because the conventional CD21⁻CD27⁻ gate captures only 44.7% of them; CD11c is the best single surface marker (see Sutton2021 - Alternative Lineage B Cells in Vaccination and Infection, n=4 CITE-seq). Infection and autoimmunity amplify, not create, this compartment.

  • T-bet and CD11c are the unifying axis. Across SLE, COVID-19, and malaria the cluster is defined by T-bet (TBX21) and CD11c (ITGAX), with FCRL5 and loss of CXCR5 (see T-bet, CD11c, FCRL5; Jenks2018 - DN2 B Cells and EF Pathway in SLE, Sutton2021 - Alternative Lineage B Cells in Vaccination and Infection).

  • First dengue evidence. CD21⁻CD11c⁺ B cells within the IgD⁻CD27⁻ gate (DN2-phenotype) are expanded in acute dengue, driven by the Tph→IL-21 axis — the first demonstration of this cluster in dengue (see Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue, n=170 acute dengue, multi-color FCM). DENV-specific CD27⁻CD21⁻ “atypical” memory also selectively accumulates with repeat DENV exposure (see Singh2026 - DENV-Specific Memory B Cell Subsets, n=18 pediatric).

  • Why this cluster anchors the wiki’s antibody-output question. Its output is characteristically near-germline, cross-reactive, and polyreactive — the property that links (in the bridge-wiki/ synthesis) to autoantibodies (molecular mimicry) on one face and non-neutralizing/ADE antibodies on the other. The atypical/plasmablast compartment is the proposed cellular source; the link is SLE-imported and unproven in dengue (see ../bridge-wiki/).

  • “ABC” is a superset that only partly overlaps “DN” — the labels are not interchangeable. The age-associated B cell population comprises CD27⁺, IgD⁺, and predominantly IgD⁻CD27⁻ cells; only the IgD⁻CD27⁻ subset corresponds to DN2. CD27⁺ and IgD⁺ ABCs are not DN, and DN subsets lacking CD11c/T-bet (DN1, DN3, DN4) are not ABCs (see Lamprinou2026 - ABCs and DN B Cells, opinion, citing Tangye 2023 / Jenks 2018). This refines the ABC row of the synonymy map above: in current usage “ABC” denotes murine cells, with human DN2 as the closest counterpart — but the correspondence is partial and context-dependent, and detailed ABC-specific biology now lives on Age-Associated B Cell.

  • ABCs are antigen-experienced and at least partly T-help-dependent — not inflammatory bystanders. Converging lines: ABCs are found within the antigen-specific pool after immunization in mice and humans; some express classical MBC markers; some carry somatically hypermutated BCRs; they respond to antigen restimulation; ABC frequencies fall significantly in patients with CD40/CD40L mutations; and ABCs do not develop in mice with a fixed BCR specificity under steady state. In autoimmunity they are proposed to derive from self-antigen-engaged B cells — anergic B cells can be converted into ABCs and acquire the phenotype more readily than naive B cells in vitro (see Glaros2025 - Multilayered Identity of B Cell Memory, review, citing mouse + human primaries). This settles a question the “bystander of inflammation” framing left open, and it matters for dengue: an antigen-driven, T-help-dependent population is one whose expansion should track DENV antigen load and Tph help (cf. Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue).

  • The expansion is acute-competent and self-resolving, not only chronic. ABCs expand during acute infections in mice and humans and after vaccination in humans, then contract over weeks to months (see Glaros2025 - Multilayered Identity of B Cell Memory, review). This is the kinetic frame a d5–8 acute dengue pilot needs — a transient expansion on a resolving trajectory, not a chronic accumulation.

  • A conserved transcriptional programme spans immune contexts. ABCs from individuals with malaria, HIV, and autoimmune disease show similar transcriptional profiles, arguing for a shared differentiation trajectory rather than disease-specific phenocopies (see Glaros2025 - Multilayered Identity of B Cell Memory, review, citing Holla 2021 cross-disease human transcriptomics). This is the strongest evidence yet against the “merely similar look-alikes” position under Contradictions below — though it remains transcriptomic correlation across chronic settings, with dengue untested.

  • ★ ZEB2 is now the leading candidate for the cross-context ABC driver, in both mice and humans — and is dual-edged. B-cell-specific Zeb2 deletion improved disease in a lupus mouse model but decreased GCBC numbers during persistent Plasmodium infection, i.e. the same population is pathogenic in autoimmunity and supportive of humoral immunity in persistent infection (see Glaros2025 - Multilayered Identity of B Cell Memory, review, citing two 2024 primaries). No dengue study has stained ZEB2.

  • ★ T-bet is not strictly required. CD11c⁺ ABCs still arise in infection and autoimmune models in the absence of T-bet (review, citing two mouse conditional-KO studies). Panel consequence: a T-bet-gated ABC definition will undercount a T-bet-independent CD11c⁺ fraction of unknown size — keep CD11c as the primary axis and T-bet as confirmatory (consistent with Sutton2021 - Alternative Lineage B Cells in Vaccination and Infection, where CD11c was the best single surface marker). Relevant to B Cell Panel Variant 1 Panel 4.

  • ★ In acute viral infection, most antigen-specific ABCs are generated GC-independently. GC-specific genetic fate mapping in mice assigns the majority of antigen-specific ABCs to a GC-independent pathway (see Glaros2025 - Multilayered Identity of B Cell Memory, review, citing Song 2022, mouse, one acute viral infection model). The review’s own caveat travels with the claim: whether this holds across other ABC-generating contexts “remains to be elucidated.” This is the strongest external support the wiki holds for its central premise — and it is murine.

  • ★ ABCs’ apparent inability to become plasma cells is substantially an assay artefact. The foundational “limited PC differentiation” results used soluble anti-Ig; ABCs’ high inhibitory-receptor load (FcγRIIB, and per the review FCRL5) blocks BCR signalling from soluble antigen, whereas membrane-associated antigen physically excludes the inhibitory receptors from the immune synapse and permits PC differentiation (see Glaros2025 - Multilayered Identity of B Cell Memory, review, citing Ambegaonkar 2020 — primary abstract independently verified at ingest). Positive evidence in the same direction: ABCs express PC-associated genes and show increased PC propensity in T cell coculture. See the reframed contradiction below.

  • But ABCs are functionally plastic, not obligate pre-plasmablasts. Adoptive transfer within an autoimmune mouse strain shows ABCs can additionally differentiate into GCBCs and self-renew (see Glaros2025 - Multilayered Identity of B Cell Memory, review, citing Nickerson 2023, mouse adoptive transfer). Whether the plasticity tracks prior antigenic stimulation is unresolved, as is whether ABCs act mainly via PC differentiation, antigen presentation to T cells, or both.

  • ⚠ A constraint on the cells→autoantibody bridge. The verified Ambegaonkar 2020 abstract states atypical MBCs “robustly respond to antigens that associate with cell surfaces, such as antigens in immune complexes, but are unable to respond to fully soluble antigens, such as self-antigens.” The bridge-wiki/ thesis proposes this cluster as the cellular source of dengue autoantibodies; if these cells are constitutionally poor responders to soluble self-antigen, the mechanism must route through membrane-associated or immune-complexed self-antigen. Secondary dengue is immune-complex-rich, so this is a redirection rather than a refutation — but it should be stated, not assumed away.

  • Cancro’s synonymy additions: human DN, HIV “tissue-like memory,” malaria “atypical memory,” and VAT “inflammatory”/“late memory” B cells. Cancro2020 extends the field-term list mapped onto this cluster (added to the table above): human “double-negative (DN)” cells (Ettinger and Sanz groups); HIV “tissue-like memory” B cells (Moir et al.), which lack both CD21 and CD27, are hyporesponsive to BCR cross-linking yet proliferate robustly to TLR9 (initially read as “exhausted”), with T-bet demonstrated later; malaria “atypical memory” B cells (Weiss et al. 2009), IFN-γ-driven with diverse V_H gene usage; and Frasca/Blomberg’s visceral-adipose-tissue T-bet⁺CD21⁻ “inflammatory B cells” / “late memory B cells,” which increase with age and correlate with ABC numbers (see Cancro2020 - Age-Associated B Cells, review — no original data; human and mouse, mixed).

  • ★ At least three populations sit inside a single ABC/atypical gate (F4) — direct murine confirmation of this page’s conflation problem. Within the murine CD21⁻CD23⁻ splenic pool, only ~2/3 of cells are T-bet⁺, and of those only about half are CD11c⁺ — so a single-axis “ABC” gate contains at least three overlapping-but-distinct populations. This reinforces the Sanz2025 ≥5-population conflation warning above, from an independent (murine, marker-quantitative) angle (see Cancro2020 - Age-Associated B Cells, review — no original data; mouse, splenic).

  • Many unique transcriptional characteristics are shared between murine and human ABCs, part of Cancro’s case for treating human DN cells as the ABC counterpart — while the review elsewhere cautions that phenotypic overlap does not guarantee transcriptomic identity, consistent with this wiki’s existing “ABC ≈ DN2 phenotypically, not transcriptomically” position (see Cancro2020 - Age-Associated B Cells, review — no original data; mouse and human).

  • A fourth naming scheme, orthogonal to DN1-4: DN^low / DN^int / DN^hi by CD19 intensity. Szelinski et al. (2022) subdivide the IgD⁻CD27⁻ compartment by CD19 staining intensity plus CXCR5 rather than by CD11c/CD21/T-bet: DN^int (CD19^int CXCR5⁺), DN^hi (CD19^hi CXCR5⁻), DN^low (CD19^low CXCR5⁻). ⚠ Beckers’ body text prints DN^low as CXCR5⁺; Table 1 of the same review and Szelinski’s own title (“antigen-experienced CXCR5⁻CD19low B cells”) both say CXCR5⁻ — the wiki reads the body text as a typo. On the CXCR5⁻ reading, DN^low lands in DN3 territory rather than constituting a fourth population. DN^int and DN^hi map approximately onto DN1 and DN2. DN^low is presented as a new antigen-experienced subset, increased in SLE, that lacks CD11c yet shares the phenotype and transcriptome of plasmablasts. DN^low + DN^hi are reported elevated in SLE, pSS, RA and COVID-19 (see Beckers2023 - Origins and Functions of DN B Cells, review, citing Szelinski 2022).

  • ★ Why DN^low matters more than another label: it is a candidate effector subset that CD11c-gated panels cannot see. Every DN2-focused gating strategy in this wiki uses CD11c as the effector discriminator. A CD11c⁻, plasmablast-transcriptome population in the DN compartment is assigned to DN3 by the standard scheme — which is exactly where Sanz2025 already places Szelinski’s cells — so it is missed by any panel that treats DN3 as a residual bin rather than an effector one. This is a different failure mode from the Sutton2021 - Alternative Lineage B Cells in Vaccination and Infection CITE-seq finding (where CD11c was the superior marker and CD21⁻CD27⁻ was the deficient one) — here CD11c itself is the marker that fails. Neither claim is independently validated in this wiki’s corpus and they point in opposite directions; both are open. See DN3 B Cell, CD11c, Conventional Flow Cytometry.

  • Review-level restatement of the overlap problem: DN B cells “overlap to some extent with CD21^-/low or CD11c^hi age-associated B cells (ABCs) or atypical memory B cells,” and DN cells have additionally been described using CD11c, CD21, T-bet and CXCR5 in varying combinations. The review’s own stated remedy — “the identification of DN subsets using uniform classifications and phenotypes is crucial to take the next step” — matches the Sanz2025 position already on this page, from an independent group (see Beckers2023 - Origins and Functions of DN B Cells, review).

  • ⚠ [2026-08-27] Another incompatible “ABC-like” definition enters the literature — this one CD27-POSITIVE. In IgG4-related disease, an “ABC-like” population was gated as IgD⁻CD27⁺CXCR5⁻, explicitly including both CD11c⁺ and CD11c⁻ cells (“given the many definitions of ABC cells”), with no T-bet. It expanded in disease while classic CXCR5⁺ switched memory contracted (both p<0.01, n=38). This population is CD27-positive and therefore does not intersect the DN compartment at all, and it is neither the CD11c⁺T-bet⁺ ABC of the murine literature nor the DN2 of the SLE literature. It is a third thing wearing the same name — a concrete addition to this page’s synonymy problem, and a reason to check the actual gate before pooling any “ABC” frequency across studies (see Allard-Chamard2023 - DN3 B Cells Infiltrate Inflamed Tissues, n=38, 13-colour FCM).

  • ★ The umbrella spans at least two phenotypically opposite cells — stated here in 2019, six years before the consensus said the same. The reciprocal FcRL4/FCRL5 pattern between HIV and SLE DN cells is direct phenotypic evidence for an anergic FcRL4⁺ HIV/mucosal type and an activated FcRL5⁺CD11c⁺ SLE effector type under one label; the review contrasts them explicitly, calling the SLE cells activated effectors and noting the HIV cells “are thought to be anergic”. Its conclusion is that “the present ABC assignment non-specifically integrates multiple B cell populations” (see Sanz2019 - Consistent Classification of Human B Cell Populations, review — no original data), figure adapted from Jenks2018 - DN2 B Cells and EF Pathway in SLE). This matters for scope: the wiki’s infectious-disease case is partly built by transfer from autoimmunity, and this review says the transfer is not phenotypically free. Compare Eisenbarth2025 - A Roadmap for Defining Extrafollicular B Cell Responses, which reaches the same conclusion by a different route and recommends retiring the acronym.

  • ★ A mechanism for conditional PC capacity: T-bet is permissive, not instructive. The wiki’s defensible middle position on atypical B cell PC output is conditional capacity (see Contradictions). Stone supplies a candidate mechanism for the condition. T-bet does not induce the PC programme at all — it represses the IFN-γ-driven inflammatory brake (NF-κB, TLR, STAT/IRF) that otherwise holds an activated B cell in an effector state. Adding an NF-κB activator or TLR7/9 ligands to wild-type Be1 cultures reproduced the Tbx21^−/−^ ASC defect without affecting proliferation (see Stone2019 - T-bet Promotes ASC Differentiation by Limiting IFN-gamma Inflammation, mouse, in vitro, ≥2–4 independent experiments). ⚠ Mouse Be1/Be2 co-culture, not human atypical B cells — the model is proposed for, not demonstrated in, the population this page describes.

  • Necessity for formation and necessity for output are separate questions. Stone’s data indicate T-bet is required for ASC differentiation in a type-1 cytokine environment but dispensable in an IL-4-dominated one, and required for memory B cell differentiation but not memory maintenance (see Stone2019 - T-bet Promotes ASC Differentiation by Limiting IFN-gamma Inflammation, mouse). Set against the evidence that CD11c⁺ ABCs still form without T-bet (Du 2019 / Levack 2020 via Glaros2025 - Multilayered Identity of B Cell Memory), this means the wiki should not use evidence about ABC formation to settle questions about ABC output, or vice versa. See T-bet Contradictions.

  • The in vitro-generated human T-bet^hi^ population is explicitly equated with the mouse ABC cluster by its authors. The IFN-γ-driven CD11c^hi^CXCR5^neg^ B_DN_ product is described as similar both to the DN2 cells of SLE patients and to “the CD11c^hi^ Age-Associated B cells (ABCs) that accumulate in aged and autoimmune mice and humans” (see Zumaquero2019 - IFN-gamma Programs T-bet-hi B Cells for ASC Differentiation, human, n=20 HD + n=40 SLE + in vitro reconstruction). This matters for the synonymy map on this page: it is a constructive identification — the same phenotype was built from ordinary naive B cells with a defined cytokine set — rather than an inference from marker overlap between two observed populations. It supports the wiki’s position that the atypical/ABC/DN2 labels describe a reachable state, and see Sanz2019 - Consistent Classification of Human B Cell Populations for the corollary that several different starting populations converge on it.

  • Class switching without affinity maturation is a repertoire signature of the atypical compartment, shown here in fate-mapped cells rather than inferred. Full-length Ig sequencing of murine T-bet⁺CD11c⁺ B cells found 41.6% of sequences mutated vs 61.5% in GC, total mutation load 0.64% vs 0.99%, CDR replacement mutations 0.66% vs 1.21% at similar silent frequencies, and <10% clonal overlap with GC B cells with early bifurcation in lineage trees — while isotype usage was indistinguishable from GC (see Song2022 - Tfh Outside Germinal Centers Drive T-bet CD11c B Cells, mouse, LCMV-Armstrong, Ig-seq n=3 mice). ⚠ Murine and acute; the human atypical populations this page otherwise describes come from chronic infection and autoimmunity.

Contradictions & Debates

  • Is “atypical B cell” a useful category at all? Sanz2025 argues no — the precise DN / alternative-lineage nomenclature should replace it. This page keeps “atypical” only as a field-recognisable umbrella; the sub-pages remain the actual units of evidence.

  • Are the cross-disease populations identical or merely similar? Whether DN2/atypical cells in SLE, dengue, COVID-19, and malaria are the same population or phenotypic look-alikes is unresolved (see Sanz2025 - Human Atypical B Cells Overview, Double-Negative B Cell).

  • Obligate pre-plasmablasts, or alternative memory? Sutton2021 finds no PC-maintenance genes in atBC clusters (challenging the EF pre-plasmablast model outside SLE), reconciled as context-dependent (see DN2 B Cell, Sutton2021 - Alternative Lineage B Cells in Vaccination and Infection). [2026-08-16] A third position now exists. Glaros2025 - Multilayered Identity of B Cell Memory attributes the functional half of this debate largely to stimulation mode: the classic “ABCs differentiate poorly into PCs” results used soluble anti-Ig, which ABCs cannot respond to because of their inhibitory-receptor load, while membrane-associated antigen restores PC differentiation. This does not dissolve the contradiction — Sutton’s finding is transcriptomic (no PC-programme genes at steady state), not a stimulation assay, so the two are not in direct conflict — but it means the field’s functional prior was built on an assay that systematically disadvantaged the cell type under test. Current best reading: ABCs are capable of PC differentiation under the right antigen presentation, primed for it in some contexts (PC-gene expression, T-coculture propensity), and yet plastic rather than committed (they can also become GCBCs and self-renew). “Obligate pre-plasmablast” is the position with the least support.

  • Is T-bet a defining feature or a frequent correlate? This page and T-bet describe T-bet as the unifying axis with CD11c. Glaros2025 - Multilayered Identity of B Cell Memory reports CD11c⁺ ABCs arising without T-bet in both infection and autoimmune models, and promotes ZEB2 as the shared programme-imposing factor instead. Not a flat contradiction — T-bet remains the dominant correlate in human disease cohorts — but the wiki should stop treating T-bet positivity as definitional and treat it as a confirmatory marker of one (major) ABC state.

  • Is ABC even the same as DN2 where they overlap? Even within the shared T-bet⁺CD11c⁺ phenotype, comparative transcriptomics show ABCs are distinct from other CD11c⁺ subsets including DN2 — elevated cytokine/chemokine expression not seen in the others (see Age-Associated B Cell, Lamprinou2026 - ABCs and DN B Cells, opinion, citing Maul 2021). So the “ABC ≈ DN2” shorthand is a phenotypic approximation, not a transcriptomic identity.

  • DN granularity: three subsets or four? Most wiki pages (after Sanz2025) use DN1/DN2/DN3; Lamprinou2026 - ABCs and DN B Cells uses a four-subset scheme adding DN4 (CXCR5⁺CD11c⁻T-bet⁻, allergy-associated) — ⚠ but that phenotype is contradicted by the primary: Allard-Chamard2023 - DN3 B Cells Infiltrate Inflamed Tissues gates DN4 as CXCR5⁺CD11c⁺ (Fig. 1B/1C and the tissue marker-validation panel Fig. 6C); CXCR5⁺CD11c⁻ is DN1’s phenotype. See the boxed note and Contradictions entry on Double-Negative B Cell — the wiki does not resolve it. This is nomenclature drift rather than a factual contradiction, but it adds DN4 to the wiki’s vocabulary (detailed on Double-Negative B Cell).

  • ★ A second, independent call to retire the term — this one from a twelve-author consensus including Sanz himself. The “is atypical a useful category” debate above rested on Sanz2025 alone. Eisenbarth2025 - A Roadmap for Defining Extrafollicular B Cell Responses places “atypical B cells” in its Box 1 tier of “terms to avoid or carefully define because of potential confusion”, on two grounds. First, the acronym ABC has four incompatible expansions in current use — age-associated, autoimmunity-associated, atypical, and activated (CD71⁺) B cells — which name overlapping but non-identical populations. Second, and more pointedly: “atypical is subjective in regard to what B cells are expected to express.” The category is defined by deviation from an unstated norm, so it cannot be stable across studies with different panels. The Perspective’s operative recommendation is “ABC should not be used to infer an EF origin” — the specific inference this wiki has to be most careful about. This page’s existing framing (umbrella term retained for field-recognisability; sub-pages carry the evidence) survives, but the umbrella should now be described as contested by consensus rather than merely by one review (see Eisenbarth2025 - A Roadmap for Defining Extrafollicular B Cell Responses, consensus Perspective, 12 authors, no primary data).

Age-Associated B Cell, Double-Negative B Cell, DN2 B Cell, DN3 B Cell, Activated Naive B Cell, Plasmablast, T-bet, ZEB2, CD11c, FCRL5, CXCR5, Extrafollicular Response, Memory B Cell, Early Memory B Cell, Tissue-Resident Memory B Cell

Analysis: Why DN B Cells Matter - Disease Relevance and Infectious Disease Case — why this cluster matters in disease and what the corpus does and does not support in infection; includes the protective/pro-immunity counter-case and the autoimmunity→infection transfer problem., GC-Independent Response

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