Aberrant B Cell Selection and Activation in Systemic Lupus Erythematosus

Background:Systemic lupus erythematosus (SLE) is characterized by two pathogenic key signatures, type I interferon (IFN) (1.) and B-cell abnormalities (2.). How these signatures are interrelated is not known. Type I-II IFN trigger activation of Janus kinase (JAK) – signal transducer and activator of transcription (STAT).Objectives:JAK-STAT inhibition is an attractive therapeutic possibility for SLE (3.). We assess STAT1 and STAT3 expression and phosphorylation at baseline and after IFN type I and II stimulation in B-cell subpopulations of SLE patients compared to other autoimmune diseases and healthy controls (HD) and related it to disease activity.Methods:Expression of STAT1, pSTAT1, STAT3 and pSTAT3 in B and T-cells of 21 HD, 10 rheumatoid arthritis (RA), 7 primary Sjögren’s (pSS) and 22 SLE patients was analyzed by flow cytometry. STAT1 and STAT3 expression and phosphorylation in PBMCs of SLE patients and HD after IFNα and IFNγ incubation were further investigated.Results:SLE patients showed substantially higher STAT1 but not pSTAT1 in B and T-cell subsets. Increased STAT1 expression in B cell subsets correlated significantly with SLEDAI and Siglec-1 on monocytes, a type I IFN marker (4.). STAT1 activation in plasmablasts was IFNα dependent while monocytes exhibited dependence on IFNγ.Figure 1.Significantly increased expression of STAT1 by SLE B cells(A) Representative histograms of baseline expression of STAT1, pSTAT1, STAT3 and pSTAT3 in CD19+ B cells of SLE patients (orange), HD (black) and isotype controls (grey). (B) Baseline expression of STAT1 and pSTAT1 or (C) STAT3 and pSTAT3 in CD20+CD27-, CD20+CD27+ and CD20lowCD27high B-lineage cells from SLE (orange) patients compared to those from HD (black). Mann Whitney test; ****p≤0.0001.Figure 2.Correlation of STAT1 expression by SLE B cells correlates with type I IFN signature (Siglec-1, CD169) and clinical activity (SLEDAI).Correlation of STAT1 expression in CD20+CD27- näive (p<0.0001, r=0.8766), CD20+CD27+ memory (p<0.0001, r=0.8556) and CD20lowCD27high (p<0.0001, r=0.9396) B cells from SLE patients with (A) Siglec-1 (CD169) expression on CD14+ cells as parameter of type I IFN signature and (B) lupus disease activity (SLEDAI score). Spearman rank coefficient (r) was calculated to identify correlations between these parameters. *p≤0.05, **p≤0.01. (C) STAT1 expression in B cell subsets of a previously undiagnosed, active SLE patient who was subsequently treated with two dosages of prednisolone and reanalyzed.Conclusion:Enhanced expression of STAT1 by B-cells candidates as key node of two immunopathogenic signatures (type I IFN and B-cells) related to important immunopathogenic pathways and lupus activity. We show that STAT1 is activated upon IFNα exposure in SLE plasmablasts. Thus, Jak inhibitors, targeting JAK-STAT pathways, hold promise to block STAT1 expression and control plasmablast induction in SLE.References:[1]Baechler EC, Batliwalla FM, Karypis G, Gaffney PM, Ortmann WA, Espe KJ, et al. Interferon-inducible gene expression signature in peripheral blood cells of patients with severe lupus. Proc Natl Acad Sci U S A. 2003;100(5):2610-5.[2]Lino AC, Dorner T, Bar-Or A, Fillatreau S. Cytokine-producing B cells: a translational view on their roles in human and mouse autoimmune diseases. Immunol Rev. 2016;269(1):130-44.[3]Dorner T, Lipsky PE. Beyond pan-B-cell-directed therapy - new avenues and insights into the pathogenesis of SLE. Nat Rev Rheumatol. 2016;12(11):645-57.[4]Biesen R, Demir C, Barkhudarova F, Grun JR, Steinbrich-Zollner M, Backhaus M, et al. Sialic acid-binding Ig-like lectin 1 expression in inflammatory and resident monocytes is a potential biomarker for monitoring disease activity and success of therapy in systemic lupus erythematosus. Arthritis Rheum. 2008;58(4):1136-45.Disclosure of Interests:Arman Aue: None declared, Franziska Szelinski: None declared, Sarah Weißenberg: None declared, Annika Wiedemann: None declared, Thomas Rose: None declared, Andreia Lino: None declared, Thomas Dörner Grant/research support from: Janssen, Novartis, Roche, UCB, Consultant of: Abbvie, Celgene, Eli Lilly, Roche, Janssen, EMD, Speakers bureau: Eli Lilly, Roche, Samsung, Janssen

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The expansion of activated naive DNA autoreactive B cells and its association with disease activity in systemic lupus erythematosus patients

Arthritis Research & Therapy ◽

10.1186/s13075-021-02557-0 ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

Kittikorn Wangriatisak ◽

Chokchai Thanadetsuntorn ◽

Thamonwan Krittayapoositpot ◽

Chaniya Leepiyasakulchai ◽

Thanitta Suangtamai ◽

...

Keyword(s):

Systemic Lupus Erythematosus ◽

B Cells ◽

Disease Activity ◽

B Cell ◽

Lupus Erythematosus ◽

Systemic Lupus ◽

Autoreactive B Cells ◽

Dsdna Antibody ◽

Cell Subpopulations ◽

B Cell Subsets

Abstract Background Autoreactive B cells are well recognized as key participants in the pathogenesis of systemic lupus erythematosus (SLE). However, elucidating the particular subset of B cells in producing anti-dsDNA antibodies is limited due to their B cell heterogeneity. This study aimed to identify peripheral B cell subpopulations that display autoreactivity to DNA and contribute to lupus pathogenesis. Methods Flow cytometry was used to detect total B cell subsets (n = 20) and DNA autoreactive B cells (n = 15) in SLE patients’ peripheral blood. Clinical disease activities were assessed in SLE patients using modified SLEDAI-2 K and used for correlation analyses with expanded B cell subsets and DNA autoreactive B cells. Results The increases of circulating double negative 2 (DN2) and activated naïve (aNAV) B cells were significantly observed in SLE patients. Expanded B cell subsets and DNA autoreactive B cells represented a high proportion of aNAV B cells with overexpression of CD69 and CD86. The frequencies of aNAV B cells in total B cell populations were significantly correlated with modified SLEDAI-2 K scores. Further analysis showed that expansion of aNAV DNA autoreactive B cells was more related to disease activity and serum anti-dsDNA antibody levels than to total aNAV B cells. Conclusion Our study demonstrated an expansion of aNAV B cells in SLE patients. The association between the frequency of aNAV B cells and disease activity patients suggested that these expanded B cells may play a role in SLE pathogenesis.

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OP0039 ALPN-303, AN ENHANCED, POTENT DUAL BAFF/APRIL ANTAGONIST ENGINEERED BY DIRECTED EVOLUTION FOR THE TREATMENT OF SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND OTHER B CELL-RELATED AUTOIMMUNE DISEASES

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.727 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 21.2-21

Author(s):

S. R. Dillon ◽

L. S. Evans ◽

K. E. Lewis ◽

J. Yang ◽

M. W. Rixon ◽

...

Keyword(s):

Systemic Lupus Erythematosus ◽

Autoimmune Diseases ◽

B Cell ◽

Directed Evolution ◽

Human Lymphocyte ◽

Lupus Erythematosus ◽

Plasma Cells ◽

Systemic Lupus ◽

Cynomolgus Monkeys

Background:BAFF and APRIL are TNF superfamily members that form homo- and heteromultimers that bind TACI and BCMA on B cells; BAFF also binds BAFF-R. BAFF and APRIL support B cell development, differentiation, and survival, particularly for plasmablasts and plasma cells, and play critical roles in the pathogenesis of B cell-related autoimmune diseases. In nonclinical models, inhibition of either BAFF or APRIL alone mediates relatively modest effects, whereas their co-neutralization dramatically reduces B cell function, including antibody production. Fc fusions of wild-type (WT) TACI (e.g. atacicept and telitacicept) target both BAFF and APRIL and have demonstrated promising clinical potential in e.g. systemic lupus erythematosus (SLE) and IgA nephropathy but have not yet clearly exhibited long-term and/or complete disease remissions.Objectives:To generate a dual BAFF/APRIL antagonist with inhibitory activity superior to WT TACI and BCMA and with the potential to improve clinical outcomes in B cell-mediated diseases.Methods:Our directed evolution platform was used to identify a potent variant TNFR domain (vTD) of TACI that exhibits significantly enhanced affinity for BAFF and APRIL as compared to WT TACI; this TACI vTD domain was fused to a human IgG Fc to generate the therapeutic candidate ALPN-303. ALPN-303 was evaluated for functional activity in: 1) human lymphocyte assays, 2) the NOD.Aec1Aec2 spontaneous model of Sjogren’s syndrome (SjS), 3) the bm12-induced mouse model of lupus, 4) the (NZB/NZW)F1 spontaneous model of lupus, and 5) preclinical rodent and cynomolgus monkey pharmacokinetic/pharmacodynamic studies.Results:ALPN-303 inhibited BAFF- and APRIL-mediated signaling in vitro in human lymphocyte assays, with significantly lower IC50 values than WT TACI-Fc and belimumab comparators. In all mouse models evaluated, administration of ALPN-303 rapidly and significantly reduced key lymphocyte subsets including plasma cells, germinal center B cells, and follicular T helper cells. ALPN-303 significantly reduced autoantibodies and sialadenitis in the spontaneous SjS model, inhibited glomerular IgG deposition in the bm12-induced model of lupus, and potently suppressed anti-dsDNA autoAbs, blood urea nitrogen levels, proteinuria, sialadenitis, kidney lesions, and renal immune complex deposition in the NZB/W lupus model. As compared to WT TACI-Fc, ALPN-303 exhibited higher serum exposure and significantly and persistently decreased titers of serum IgM, IgG, and IgA antibodies in mice and cynomolgus monkeys (Figure 1).Figure 1.ALPN-303 induces more potent suppression, as compared to WT TACI-Fc, of serum immunoglobulins following a single 9 mg/kg IV infusion (on Day 0; arrows) in female cynomolgus monkeys.Conclusion:ALPN-303 is a potent BAFF/APRIL antagonist derived from our directed evolution platform that consistently demonstrates encouraging immunomodulatory activity and efficacy in vitro and in vivo, superior in preclinical studies to anti-BAFF antibody and WT TACI-Fc. This novel Fc fusion molecule demonstrates favorable preliminary developability characteristics, including higher serum exposures and more potent immunosuppressive activities, which may enable lower clinical doses and/or longer dosing intervals than WT TACI-Fc therapeutics. ALPN-303 may thus be an attractive development candidate for the treatment of multiple autoimmune and inflammatory diseases, particularly B cell-related diseases such as SLE, SjS, and other connective tissue diseases. Preclinical development is underway to enable the initiation of clinical trials later this year.Disclosure of Interests:Stacey R. Dillon Shareholder of: Alpine Immune Sciences, Bristol Myers Squibb, Employee of: Alpine Immune Sciences, Bristol Myers Squibb, Lawrence S. Evans Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Katherine E. Lewis Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Jing Yang Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Mark W. Rixon Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Joe Kuijper Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Dan Demonte Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Janhavi Bhandari Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Steve Levin Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Kayla Kleist Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Sherri Mudri Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Susan Bort Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Daniel Ardourel Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Michelle A. Seaberg Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Rachel Wang Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Chelsea Gudgeon Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Russell Sanderson Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Martin F. Wolfson Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Jan Hillson Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences, Stanford L. Peng Shareholder of: Alpine Immune Sciences, Employee of: Alpine Immune Sciences

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AB0818 ADVERSE EVENTS UNDER B-CELL DIRECTED THERAPIES IN A LARGE SINGLE-CENTER COHORT OF PATIENTS WITH RHEUMATOID ARTHRITIS, SYSTEMIC LUPUS ERYTHEMATOSUS, ANCA-ASSOCIATED VASCULITIS AND RENAL DISEASES

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.1214 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 1433.1-1433

Author(s):

J. G. Rademacher ◽

V. Korendovych ◽

P. Korsten

Keyword(s):

Rheumatoid Arthritis ◽

Systemic Lupus Erythematosus ◽

Adverse Events ◽

B Cell ◽

Clinical Data ◽

Lupus Erythematosus ◽

Infectious Complications ◽

Single Center ◽

Systemic Lupus ◽

Anca Associated Vasculitis

Background:The anti-CD20 antibody rituximab (RTX) is approved for the treatment of rheumatoid arthritis (RA) and ANCA-associated vasculitis (AAV). In addition, RTX is used in a wide range of autoimmune diseases. Belimumab (BEL) is an anti-BAFF antibody approved for the treatment of non-renal systemic lupus erythematosus (SLE) in Europe. These agents are generally well-tolerated but severe adverse events (AEs) can occur. The frequency of and factors associated with AEs are currently unknown.Objectives:To identify adverse events with the use of B-cell directed therapies in a large population of RA, AAV, and SLE.Methods:This is a single-center retrospective cohort study using routine clinical data over a ten-year period (2010-2020). We recorded epidemiological and clinical data of patients receiving either BEL or RTX. Data included age, gender, type of disease, number and efficacy of infusions, patient-years and concomitant treatment. Patient records were screened for AEs, such as infections, anaphylaxis, occurrence of malignant disease, laboratory abnormalities and immunoglobulin (Ig) deficiency. Between group comparisons were performed.Results:Database screening yielded 445 patients treated with RTX and 23 with BEL. After exclusion of patients with incomplete data, 425 RTX and 23 BEL patients were analyzed.Our preliminary analysis of a sample of 60 of these 448 patients (184 patient-years) resulted in 43 patients (72%) with RA, 8 patients with AAV (13%), 5 patients with a renal disease, and 4 patients with mixed connective tissue disease, as well 23 SLE patients. 46 (77%) were female. In RA, a median of 13 treatments of 1000 mg were administered, corresponding to 3.37 patient-years per patient. Primary non-response occurred in 2 patients, secondary non-response in 13 patients. For AAV, a median of 8.4 treatments were given (3.3 patient-years), no treatment failure was detected. SLE patients received a median of 15 treatments.15 patients had infectious complications during treatment, 11 needed treatment. Herpes zoster infection occurred in 3 patients with RA. Three of the 8 patients with AAV had an infection requiring treatment. In SLE patients, only 2 developed infectious complications, and no Ig-deficiency occurred.Lymphopenia was the most common laboratory abnormality detected in 25 patients with RTX, 19 of whom had RA. Ig deficiency was common in RA, affecting 30% of patients. Deficiency of IgM and IgG was recognized in 5 patients each; 1 patient had low levels IgA.Neither the maintenance prednisolone dosage nor Ig deficiency were associated with risk for infection. However, lymphopenia appeared to be associated with risk for infection.Conclusion:Our preliminary data observe a 184 patient-year period. RTX and BEL were generally associated with few AEs. RA patients frequently had laboratory abnormalities (lymphopenia, Ig-deficiency) which did not necessarily translate to clinical events. Infections were more common in AAV, BEL was the best tolerated B-cell directed agent. Overall, our data are reassuring, but we suggest a more careful vigilance in AAV patients.Disclosure of Interests:Jan-Gerd Rademacher: None declared, Viktor Korendovych: None declared, PETER KORSTEN Speakers bureau: Abbvie, Sanofi Aventis, GSK, Chugai, Boehringer-Ingelheim, Novartis, Consultant of: Lilly, Gilead, Boehringer-Ingelheim, Novartis, GSK, Grant/research support from: GSK

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