EULAR 2026 Highlights – SLE and APS

Belimumab step-down dose spacing in patients with systemic lupus erythematosus in persistent clinical remission: experience from a multicentre cohort

Abstract format and assignment number: Poster presentation, POS1052

Presenting author: A. Bartoletti (Italy)

This multicentre retrospective study (Milan Lupus Consortium, 4 centres) evaluated the feasibility and safety of belimumab (BEL) dose spacing and withdrawal in SLE patients in long-standing remission. Among 152 BEL-treated patients, 22 (14.5%) underwent spacing. These patients had longer remission duration (64 vs 25 months), less serological activity and lower glucocorticoid use. No SLE flares occurred during follow-up; seven discontinued BEL for sustained remission. Progressive dose spacing with close monitoring appears safe in selected patients.

Single-cell and spatial transcriptomic profiling reveals systemic and tissue immune remodeling in SLE treated with anifrolumab

Abstract format and assignment number: Poster presentation, POS0672

Presenting author: I. Martínez-Garcia (Spain)

This study combined single-cell (CITE-seq) and spatial transcriptomics (CosMx) to map how anifrolumab remodels immunity in SLE, profiling PBMCs from 15 patients and skin from three across treatment. At flare, naïve CD4/CD8 T cells were expanded; after treatment they contracted while effector-memory T cells rose. Interferon signaling was downregulated across B cells, T cells and myeloid populations, with interferon scores and IFN-producing skin cells normalizing by 12 months. Anifrolumab coordinately restored systemic and tissue immune homeostasis.

Memantine improves neuropsychological function in systemic lupus erythematosus: results from a phase II randomized, double-blind, placebo-controlled trial

Abstract format and assignment number: Poster presentation, POS0701

Presenting author: L. Crofford (USA)

ClearMEMory (NCT03527472), a phase II randomized, double-blind, placebo-controlled trial, tested whether memantine (up to 40 mg/day) improves objective neuropsychological performance in SLE. Fifty-six patients were randomized (26 memantine, 30 placebo). In the per-protocol analysis, improvement in RBANS Total Scale Index Score was greater with memantine than placebo (p=0.032), with more responders (67% vs 36%) and greater immediate-memory gains. Memantine meaningfully improved objective neuropsychological function, though fewer patients tolerated the maximum dose.

Significance of residual proteinuria in the management of lupus nephritis – insights from a prospective multi-national, longitudinal cohort study

Abstract format and assignment number: Oral presentation, OP095

Presenting author: J. Kikuchi (Japan)

Using the Asia Pacific Lupus Collaboration cohort (2,477 lupus nephritis patients, 13 countries), this study examined the prognostic significance of time-averaged proteinuria (TAM UPCR). Higher TAM UPCR predicted greater renal decline: TAM UPCR >0.1 g/mmol outside LLDAS-50 independently increased the risk of creatinine doubling, severe flares and damage accrual. Even low-grade elevation was associated with adverse outcomes, while LLDAS-50 was protective. Findings support combined targets of LLDAS attainment and minimal residual proteinuria in lupus nephritis.

Toward a “virtual biopsy”: in vivo LC-OCT characterization of acute, subacute, and chronic cutaneous lupus erythematosus and differential diagnosis with rosacea: a pilot study

Abstract format and assignment number: Oral presentation, OP099

Presenting author: R. Ventura (Italy)

This pilot study assessed line-field confocal optical coherence tomography (LC-OCT) as a non-invasive “virtual biopsy” for cutaneous lupus erythematosus (CLE). Forty-five participants were imaged (30 CLE—16 acute, 5 subacute, 9 chronic—and 15 rosacea). LC-OCT revealed layer-specific, stage-dependent signatures: interface-dermatitis features strongly distinguished acute CLE, whereas rosacea showed a vascular-folliculocentric profile with Demodex mites. LC-OCT captured histopathologic correlates in vivo and separated CLE from rosacea, suggesting a role in reducing unnecessary biopsies.

The single-cell multi-omic profiling of placental trophoblast differentiation in obstetric antiphospholipid syndrome

Abstract format and assignment number: Poster presentation, POS0038

Presenting author: R. Gao (China)

Using CITE-seq and spatial transcriptomics (with organoid and immunofluorescence validation), this study mapped placental trophoblast differentiation in obstetric antiphospholipid syndrome (OAPS). In OAPS with severe pre-eclampsia and/or fetal growth restriction, extravillous trophoblast differentiation was inhibited and syncytiotrophoblast differentiation enhanced, with reduced EVT transcription factors (DLX5/6, ZNF439). Enhanced pro-inflammatory crosstalk between CCR2+ macrophages, CD16bright NK cells, cytotoxic T cells and trophoblast was identified. Promoting trophoblast differentiation and curbing inflammation may offer new OAPS treatment strategies.

Predictors of thrombotic recurrence in antiphospholipid syndrome: the role of aPL profile and aGAPSS score

Abstract format and assignment number: Poster presentation, POS0042

Presenting author: V. Lainis (Greece)

This retrospective Greek cohort study examined predictors of thrombotic recurrence in 100 patients with APS classified by the 2023 ACR/EULAR criteria. During follow-up, 44% experienced a new thrombotic event. On multivariable analysis, lupus anticoagulant positivity (OR 3.46), triple positivity (OR 5.54), double positivity (OR 3.45) and a higher aGAPSS at diagnosis (OR 1.43) independently predicted recurrence. Triple positivity was the sole independent predictor of multiple thrombotic events, identifying a particularly high-risk group.

Effectiveness and safety of primary thromboprophylaxis in antiphospholipid antibody carriers by serological 2023 ACR/EULAR domains

Abstract format and assignment number: Poster presentation, POS0044

Presenting author: R. Gálvez-Sánchez (Spain)

This study assessed primary thromboprophylaxis in 985 asymptomatic antiphospholipid antibody carriers, classified by 2023 ACR/EULAR serological domains, over a median 2.84 years. Low-dose aspirin improved thrombotic-free survival (HR 0.51) without increasing bleeding, and remained protective even in carriers with fewer than three laboratory points (HR 0.53). P2Y12 inhibitors showed no thrombotic benefit and were linked to higher arterial events, minor bleeding and reduced bleeding-free survival. Aspirin may safely lower thrombotic risk in these carriers.

Anti-myosin Va antibodies: a novel pathogenic autoantibody in antiphospholipid syndrome

Abstract format and assignment number: Oral abstract presentation, OP0297

Presenting author: H. Jiang (China)

Using a 20,000-protein proteome microarray with targeted validation, this study identified anti-myosin Va antibodies (aMYO5A) as a novel autoantibody in antiphospholipid syndrome (APS). Serum aMYO5A was significantly elevated in APS and seronegative APS versus controls and independently associated with thrombotic risk. Mechanistically, purified aMYO5A activated endothelial cells via p38 MAPK/NF-κB, upregulating adhesion molecules, and shortened thrombus formation in vivo. Anti-MYO5A expands the serological spectrum of APS with diagnostic and prothrombotic relevance.

Morbidity and mortality in primary versus secondary antiphospholipid syndrome: a single-center study using the 2023 ACR/EULAR criteria

Abstract format and assignment number: Oral abstract presentation, OP0304

Presenting author: R. Meidan (Israel)

This single-center study compared morbidity and mortality between primary (PAPS) and secondary (SAPS) antiphospholipid syndrome in 210 patients reclassified by the 2023 ACR/EULAR criteria. Despite similar thrombotic recurrence and antibody profiles, SAPS patients had more catastrophic APS (11.9% vs 2.7%) and higher mortality (22.0% vs 10.6%). On multivariable analysis, secondary APS (HR 5.28), renal disease and older age at first event independently predicted death. Concomitant SLE marks a worse prognosis warranting tailored risk stratification.