POS0452 ABNORMALITY OF TYPE I INTERFERON SIGNALLING IN B CELLS IN PRIMARY SJÖGREN´S SYNDROME AND THE IMPACT ON LABORATORY AND CLINICAL FINDINGS

Background

B cell hyperactivity (1), autoantibody production (anti-SS-A, anti-SS-B) and hypergammaglobulinaemia as well as interferon (IFN) signature (2) play a central role in the pathogenesis of primary Sjögren´s Syndrome (pSS). The link between these hallmarks is still elusive. While treatment of pSS remains limited, an improved understanding of IFN and JAK/STAT signalling on B cells may hold promise to improve potential treatment targets and related biomarkers.

Objectives

To investigate downstream molecules of the IFN signalling pathway on B cells and their clinical impact in pSS.

Methods

Peripheral blood from 47 pSS patients and 36 matched healthy controls (HC) was obtained and permeabilized for intracellular staining. Here B and T cell markers were applied together with Signal Transducers and Activators of Transcription 1 (STAT1), STAT2, pSTAT1 and 2, Interferon Regulatory factor 9 (IRF9), IRF7 and IRF1 and analysed by using flow cytometry. Cell subsets and correlations with all markers and clinical information were subjected to statistical analyses.

Results

Compared to HC the pSS group showed significantly elevated STAT1 expression among all B cell subsets (p>0.0001) including naïve (CD27-IgD+), pre-switched (CD27+ IgD+), switched-memory (CD27+IgD-), double negative (CD27- IgD-) B cells and plasmablasts (CD27++ CD38++). Furthermore, IRF9 and STAT2 were increased among most B cell subsets.

Positive correlations were found between STAT1 and IRF9 with Siglec-1 (CD169), an IFN signature marker expressed on the surface of CD14+ monocytes (p>0.0001; r=0.633). Notably, increased levels of IRF9 positively correlates with STAT1.

Upregulated STAT1 and IRF9 within pSS B cells were associated to extraglandular manifestations, high anti-SS-A and anti-SS-B autoantibodies, high anti-nuclear antibody titers (ANA) and rheumatoid factors (IgA, IgM) in pSS patients.

Patients treated with prednisolone showed dose dependent inverse correlations of IRF9 expression among naïve-, memory-, and double negative B cells suggesting its treatment responsiveness.

Conclusion

The current data provide evidence of type I IFN on B cell subsets in pSS. Elevated STAT1, STAT2 and IRF9 expression suggest transcriptionally activity, which was evident in patients with extraglandular manifestations and elevated serologic activity.

Targeting JAK/STAT in pSS could be beneficial for patients with high STAT1 levels leading to a personalized approach for this specific subgroup of patients.

References

[1]Nocturne G, Mariette X. B cells in the pathogenesis of primary Sjögren syndrome. Nature Reviews Rheumatology. 2018;14(3):133-45.

[2]Brkic Z, Maria NI, Helden-Meeuwsen CGv, Merwe JPvd, Daele PLv, Dalm VA, et al. Prevalence of interferon type I signature in CD14 monocytes of patients with Sjögren’s syndrome and association with disease activity and BAFF gene expression. Annals of the Rheumatic Diseases. 2013;72(5):728-35.

Disclosure of Interests

None declared.

Altered increase in STAT1 expression and phosphorylation in severe COVID-19

The interferon pathway, a key antiviral defense mechanism, is being considered as a therapeutic target in COVID‐19. Both, substitution of interferon and JAK/STAT inhibition to limit cytokine storms have been proposed. However, little is known about possible abnormalities in STAT signaling in immune cells during SARS‐CoV‐2 infection. We investigated downstream targets of interferon signaling, including STAT1, STAT2, pSTAT1 and 2, and IRF1, 7 and 9 by flow cytometry in 30 patients with COVID‐19, 17 with mild, and 13 with severe infection. We report upregulation of STAT1 and IRF9 in mild and severe COVID‐19 cases, which correlated with the IFN‐signature assessed by Siglec‐1 (CD169) expression on peripheral monocytes. Interestingly, Siglec‐1 and STAT1 in CD14+ monocytes and plasmablasts showed lower expression among severe cases compared to mild cases. Contrary to the baseline STAT1 expression, the phosphorylation of STAT1 was enhanced in severe COVID‐19 cases, indicating a dysbalanced JAK/STAT signaling that fails to induce transcription of interferon stimulated response elements (ISRE). This abnormality persisted after IFN‐α and IFN‐γ stimulation of PBMCs from patients with severe COVID‐19. Data suggest impaired STAT1 transcriptional upregulation among severely infected patients may represent a potential predictive biomarker and would allow stratification of patients for certain interferon‐pathway targeted treatments.

OP0005 ELEVATED STAT1 EXPRESSION BUT NOT PHOSPHORYLATION IN LUPUS B CELLS CORRELATES WITH DISEASE ACTIVITY AND INCREASED PLASMABLAST SUSCEPTIBILITY

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

Elevated STAT1 expression but not phosphorylation in lupus B cells correlates with disease activity and increased plasmablast susceptibility

Objectives

SLE is characterized by two pathogenic key signatures, type I IFN and B-cell abnormalities. 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). JAK-STAT inhibition is an attractive therapeutic possibility for SLE. 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 with 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), seven primary Sjögren’s (pSS) and 22 SLE patients was analysed by flow cytometry. STAT1 and STAT3 expression and phosphorylation in PBMCs (peripheral blood mononuclear cells) 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. STAT1 activation in plasmablasts was IFNα dependent while monocytes exhibited dependence on IFNγ.

Conclusion

Enhanced expression of STAT1 by B-cell candidates as a 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 a promise to block STAT1 expression and control plasmablast induction in SLE.

Lyssavirus distribution in naturally infected bats from Germany

In Germany, to date three different lyssavirus species are responsible for bat rabies in indigenous bats: the European Bat Lyssaviruses type 1 and 2 (EBLV-1, EBLV-2) and the Bokeloh Bat Lyssavirus (BBLV) for which Eptesicus serotinus, Myotis daubentonii and Myotis nattereri, respectively, are primary hosts. Lyssavirus maintenance, evolution, and epidemiology are still insufficiently explored. Moreover, the small number of bats infected, the nocturnal habits of bats and the limited experimental data still hamper attempts to understand the distribution, prevalence, and in particular transmission of the virus. In an experimental study in E. serotinus a heterogeneous dissemination of EBLV-1 in tissues was detected. However, it is not clear whether the EBLV-1 distribution is similar in naturally infected animals. In an attempt to further analyze virus dissemination and viral loads within naturally infected hosts we investigated tissues of 57 EBLV-1 positive individuals of E. serotinus from Germany by RT-qPCR and compared the results with those obtained experimentally. Additionally, tissue samples were investigated with immunohistochemistry to detect lyssavirus antigen in defined structures. While in individual animals virus RNA was present only in the brain, in the majority of E. serotinus viral RNA was found in various tissues with highest relative viral loads detected in the brain. Interestingly, viral antigen was confirmed in various tissues in the tongue including deep intralingual glands, nerves, muscle cells and lingual papillae. So, the tongue appears to be a prominent site for virus replication and possibly shedding.

Anecortave acetate for the treatment of subfoveal choroidal neovascularization secondary to age-related macular degeneration

PURPOSE

Anecortave acetate is a novel angiostatic cortisene being evaluated clinically for treatment of exudative age-related macular degeneration (ARMD). A randomized, placebo-controlled, efficacy and safety dose duration study of anecortave acetate for depot suspension (3 mg, 15 mg, 30 mg) in this patient population was completed in June 2003. As part of this trial, 128 patients with subfoveal choroidal neovascularization (CNV) secondary to ARMD were enrolled and treated for up to 2 years by 18 clinical sites in the United States and European Union.

METHODS

Study patients were evaluated clinically with detailed ophthalmic examinations, general physical examinations, assessments of best-corrected logMAR visual acuity, and angiographic evaluations. The Digital Angiography Reading Center (New York City, NY) assessed lesion eligibility while the clinical investigators assessed overall patient eligibility prior to treatment. As part of this study, study medication was delivered as a posterior juxtascleral depot using a specially designed curved cannula at 6-month intervals if in the masked investigator's opinion the patient's lesion could benefit from additional treatment.

RESULTS

The 2-year efficacy results of this placebo-controlled study demonstrated that RETAANE 15 mg (anecortave acetate for depot suspension) was statistically superior to placebo for stabilization of vision (<3 logMAR line change from baseline) and for inhibition of neovascular lesion growth. There were no serious treatment-related safety issues associated with either the study medication or the procedure for administration.

CONCLUSIONS

Anecortave acetate 15 mg for depot suspension is clinically efficacious compared to placebo for treatment of subfoveal exudative ARMD lesions when administered at 6-month intervals as a posterior juxtascleral depot.