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Objectives Emerging evidence demonstrates that aPS-PT associate with thrombotic events. Genetic predisposition, including HLA-DRB1 alleles, is known to contribute to the occurrence of conventional aPL [anti-β2glycoprotein-I (anti-β2GPI) and aCL]. We investigated associations between aPS-PT and HLA-DRB1* alleles and thrombosis in SLE. Conventional aPL were included for comparison. Methods We included 341 consecutive SLE patients, with information on general cardiovascular risk factors, including blood lipids, LA and thrombotic events. aPS/PT, anti-β2GPI and aCL of IgA/G/M isotypes and LA were quantified. Results aPS/PT antibodies associated positively with HLA-DRB1*13 [odds ratio (OR) 2.7, P = 0.002], whereas anti-β2GPI and aCL antibodies associated primarily with HLA-DRB1*04 (OR 2.5, P = 0.0005). These associations remained after adjustment for age, gender and other HLA-DRB1* alleles. HLA-DRB1*13, but not DRB1*04, remained as an independent risk factor for thrombosis and APS after adjustment for aPL and cardiovascular risk factors. The association between DRB1*13 and thrombosis was mediated by aPS-PT positivity. HLA-DRB1*03, on the other hand, associated negatively with thrombotic events as well as all aPL using both uni- and multivariate analyses. HLA-DRB1*03 had a thrombo-protective effect in aPL-positive patients. Additionally, HLA-DRB1*03 was associated with a favourable lipid profile regarding high-density lipoprotein and triglycerides. Conclusions HLA-DRB1*13 confers risk for both aPS-PT and thrombotic events in lupus. The association between HLA-DRB1*13 and thrombosis is largely, but not totally, mediated through aPS-PT. HLA-DRB1*03 was negatively associated with aPL and positively with favourable lipid levels. Thus, HLA-DRB1*03 seems to identify a subgroup of SLE patients with reduced vascular risk.

ObjectiveLupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE). The pathogenesis is incompletely understood and diagnostic biomarkers are scarce. We investigated interleukin (IL) 16 as a potential biomarker for LN in a well-characterised cohort of patients with SLE.MethodsWe measured urinary (u-) and plasma (p-) levels of IL-16 in predefined patient groups using ELISA: LN (n=84), active non-renal SLE (n=63), inactive non-renal SLE (n=73) and matched population controls (n=48). The LN group included patients with recent biopsy-confirmed proliferative (PLN, n=47), mesangioproliferative (MES, n=11) and membranous (MLN, n=26) LN. Renal expression of IL-16 was investigated by immunohistochemistry. Associations between IL-16 measurements and clinical parameters and the diagnostic value for LN were explored.Resultsp-IL-16 was detected in all investigated cases and high p-IL-16 levels were observed in patients with active SLE. u-IL-16 was detected (dt-u-IL-16) in 47.6% of patients with LN, while only up to 17.8% had dt-u-IL-16 in other groups. In the LN group, 68% of patients with PLN had dt-u-IL-16, while the proportions in the MLN and MES groups were lower (11.5% and 45.5%, respectively). The highest u-IL-16 levels were detected in the PLN group. In the regression model, u-IL-16 levels differentiated PLN from other LN patient subgroups (area under the curve 0.775–0.896, pConclusionsWe demonstrate that detectable u-IL-16 can differentiate patients with PLN from those with less severe LN subtypes and active non-renal SLE. Our findings suggest that u-IL-16 could be used as a screening tool at suspicion of severe LN. Furthermore, the high IL-16 levels in plasma, urine and kidney tissue imply that IL-16 could be explored as a therapeutic target in SLE.

Background Low levels of total C4b-binding protein (C4BPt), a circulating inhibitor of the classical/lectin complement pathways, were observed in patients with antiphospholipid antibodies (aPLs) and during warfarin treatment. Objectives To investigate the associations between aPL and C4BPt in patients with persistently positive (++) aPL, with/without clinical manifestations and systemic lupus erythematosus (SLE), and in controls. Furthermore, we explored the impact of anticoagulation on C4BPt and in relation to complement activation. Methods In a cross-sectional design we investigated defined subgroups: primary (p) antiphospholipid syndrome (APS, N = 67), aPL++ individuals without clinical manifestations (aPL carriers, N = 15), SLE-aPL++ (N = 118, among them, secondary [s] APS, N = 56), aPL negative (−) SLE (SLE-aPL−, N = 291), and 322 controls. Clinical characteristics, including treatment, were tabulated. C4BPt was determined with a magnetic bead method. Complement proteins (C1q, C2, C3, C4, C3a, C3dg, sC5b-9, factor I [FI]) were measured. A mediation analysis was performed to decompose the total effect of aPL++ on C4BPt into the direct and indirect effects of aPL++ through warfarin. Results Overall, C4BPt is 20% decreased in aPL++ patients, regardless of SLE, APS, clinical manifestations, and aPL profile. C4BPt levels associate positively with complement proteins C1q, C2, C3, and C4, and negatively with complement activation product C3dg. In the SLE group, warfarin treatment contributes to approximately half of the C4BPt reduction (9%) Conclusion Both aPLs and warfarin are associated with C4BPt reduction. Complement activation in aPL++ patients may partly be explained by impaired inhibition through depressed C4BPt levels. Further studies are needed to understand the clinical implications.

Objective The heterogeneity of systemic lupus erythematosus (SLE) constitutes clinical and therapeutical challenges. We therefore studied whether unrecognized disease subgroups can be identified by using autoantibody profiling together with HLA-DRB1 alleles and immunological and clinical data. Methods An unsupervised cluster analysis was performed based on detection of 13 SLE-associated autoantibodies (double-stranded DNA, nucleosomes, ribosomal P, ribonucleoprotein [RNP] 68, RNPA, Smith [Sm], Sm/RNP, Sjogren's syndrome antigen A [SSA]/Ro52, SSA/Ro60, Sjogren's syndrome antigen B [SSB]/La, cardiolipin [CL]-Immunoglobulin G [IgG], CL-Immunoglobulin M [IgM], and β2 glycoprotein I [β2 GPI]-IgG) in 911 patients with SLE from two cohorts. We evaluated whether each SLE subgroup is associated with HLA-DRB1 alleles, clinical manifestations (n = 743), and cytokine levels in circulation (n = 446). Results Our analysis identified four subgroups among the patients with SLE. Subgroup 1 (29.3%) was dominated by anti-SSA/Ro60/Ro52/SSB autoantibodies and was strongly associated with HLA-DRB1*03 (odds ratio [OR] = 4.73; 95% confidence interval [CI] = 4.52-4.94). Discoid lesions were more common for this disease subgroup (OR = 1.71, 95% CI = 1.18-2.47). Subgroup 2 (28.7%) was dominated by anti-nucleosome/SmRNP/DNA/RNPA autoantibodies and associated with HLA-DRB1*15 (OR = 1.62, 95% CI = 1.41-1.84). Nephritis was most common in this subgroup (OR = 1.61, 95% CI = 1.14-2.26). Subgroup 3 (23.8%) was characterized by anti-s2 GPI-IgG/anti-CL-IgG/IgM autoantibodies and a higher frequency of HLA-DRB1*04 compared with the other patients with SLE. Vascular events were more common in Subgroup 3 (OR = 1.74, 95% CI = 1.2-2.5). Subgroup 4 (18.2%) was negative for the investigated autoantibodies, and this subgroup was not associated with HLA-DRB1. Additionally, the levels of eight cytokines significantly differed among the disease subgroups. Conclusion Our findings suggest that four fairly distinct subgroups can be identified on the basis of the autoantibody profile in SLE. These four SLE subgroups differ regarding associations with HLA-DRB1 alleles and immunological and clinical features, suggesting dissimilar disease pathways.

ObjectivePatients with SLE have increased risk of myocardial infarction (MI). Few studies have investigated the characteristics of SLE-related MIs. We compared characteristics of and risk factors for MI between SLE patients with MI (MI-SLE), MI patients without SLE (MI-non-SLE) and SLE patients without MI (non-MI-SLE) to understand underlying mechanisms.MethodsWe identified patients with a first-time MI in the Karolinska SLE cohort. These patients were individually matched for age and gender with MI-non-SLE and non-MI-SLE controls in a ratio of 1:1:1. Retrospective medical file review was performed. Paired statistics were used as appropriate.ResultsThirty-four MI-SLE patients (88% females) with a median age of 61 years were included. These patients had increased number of coronary arteries involved (p=0.04), and ≥50% coronary atherosclerosis/occlusion was numerically more common compared with MI-non-SLE controls (88% vs 66%; p=0.07). The left anterior descending artery was most commonly involved (73% vs 59%; p=0.11) and decreased (ConclusionIn the great majority of cases, MIs in SLE are associated with coronary atherosclerosis. Furthermore, MIs in SLE are commonly preceded by symptomatic vascular disease, calling for attentive surveillance of cardiovascular disease and its risk factors and early atheroprotective treatment.

Objective: Accumulating evidence supports an impaired health-related quality of life (HRQoL) in patients with systemic lupus erythematosus (SLE). We investigated the effects of 2 biologic treatments on HRQoL of patients with SLE. Methods: Patients with SLE from the Karolinska University Hospital treated with belimumab (n = 34) or rituximab (n = 35) were included; normative values derived from Swedish population-based controls matched for age and sex were used for the purpose of comparisons. Data were collected prospectively at treatment initiation and at months 3, 6, 12, and 24, using the Short Form 36 (SF-36) health questionnaire, the Functional Assessment of Chronic Illness Therapy–Fatigue (FACIT-Fatigue) scale, the EuroQol 5-dimension (EQ-5D) instrument, and the Stanford Health Assessment Questionnaire disability index (HAQ DI). Results: Substantial decrements from Swedish norms were observed across all SF-36 domains at baseline. Patients treated with belimumab reported gradual improvements in the SF-36 physical component summary (significant from month 12; P = 0.023) and FACIT-Fatigue (significant by month 24; P = 0.001), no changes in EQ-5D scores, and improvements in HAQ DI by month 6 (P = 0.014). Patients treated with rituximab showed rapid improvements in the SF-36 mental component summary and FACIT-Fatigue by month 3 (P = 0.031 and P = 0.007, respectively), as well as improvements in EQ-5D at month 6 (P = 0.016) and HAQ DI at month 3 (P = 0.033). Based on baseline evaluations, patients receiving antimalarial agents (n = 33) performed better in the SF-36 social functioning (P = 0.022) and mental health (P = 0.023) domains compared to patients who did not receive antimalarial agents (n = 36). Conclusion: Our results corroborated previous findings of considerable HRQoL impairments in patients with SLE. Patients' perceptions of HRQoL showed discrepant patterns over time in the 2 treatment groups and could provide additional information along with the clinical evaluation of biologic therapy in SLE. Further survey on the effects of antimalarial agents on the HRQoL of patients with SLE in larger cohorts is merited.

Objectives Antiphosphatidylserine/prothrombin complex antibodies (aPS/PT) are risk factors for thrombosis, yet further validation of their clinical relevance in different ethnic groups is required. We investigated the performance of aPS/PT of IgA/G/M isotypes among Sudanese and Swedish systemic lupus erythematosus (SLE) patients. Methods Consecutive SLE patients/matched controls from Sudan (n = 91/102) and Sweden (n = 332/163) were included. All patients fulfilled the 1982 ACR SLE classification criteria. IgA/G/M of aPS/PT, anti-cardiolipin and anti-β2glycoprotein I (anti-β2GPI) were tested in both cohorts, and lupus anticoagulant (LA) also in the Swedish cohort. Clinical antiphospholipid syndrome-related events and atherosclerosis, measured as carotid plaques were assessed for associations. Univariate and multivariate analyses adjusting for cardiovascular risk factors were performed. Results Sudanese SLE patients had higher levels of IgM aPS/PT, but using national cut-offs, the frequency of positivity was similar to Swedish patients for all isotypes. Among Swedish patients, all isotypes of aPS/PT associated with venous thromboembolism (VTE), while only IgA aPS/PT associated with arterial thrombosis (AT). aPS/PT antibodies associated strongly with LA and they were, independently, the best predictor for VTE. Double positivity for aPS/PT and anti-β2GPI associated with higher VTE risk than the conventional triple positivity. Carotid plaques did not associate with any antiphospholipid antibody. Conclusions IgA aPS/PT associated with AT, and the association of IgG/M aPS/PT with VTE outperforms LA and criteria antiphospholipid antibodies in Swedish SLE patients. Furthermore, double positivity for aPS/PT and anti-β2GPI performed better than conventional triple positivity. Future studies need to address if aPS/PT can replace LA, as this would simplify clinical procedures.

ObjectivesStudies on repeat renal biopsies in membranous LN (MLN) are limited, and evaluation of treatment response is mainly based on proteinuria. EM of renal biopsies from rituximab (RTX)-treated MLN patients has revealed resorption of sub-epithelial ICs. Whether resorption phenomena are useful for treatment evaluation, or differs between treatment regimens is not known. We studied EM findings and clinical treatment response in MLN patients after RTX vs conventional immunosuppressive treatment.MethodsTwenty-four patients with MLN and renal biopsies performed before and after treatment were included in this retrospective observational study. Laboratory data were collected at both biopsy occasions. Seven patients had received RTX and 17 had received conventional treatment (CYC, MMF or AZA). Electron micrographs of renal tissue were scored using an arbitrary scale (0–3) for the level of sub-epithelial ICs, resorption of ICs and podocyte fusion.ResultsSub-epithelial ICs decreased after treatment, however not significantly and with no difference between treatments. The resorption phenomena increased after RTX (P = 0.028), but not after conventional therapy (P = 0.29). Six out of seven (86%) RTX-treated patients had increased resorption vs 7/17 (41%) after conventional therapies (P = 0.047). Clinical responders had more pronounced resorption of ICs vs non-responders (P = 0.022).ConclusionsWe report increased resorption of ICs in repeat renal biopsies in MLN, especially after RTX treatment. Increased resorption phenomena were associated with clinical response, suggesting that EM findings may be useful for treatment evaluation in MLN. Although of limited size, the study indicates that RTX is effective both clinically and at a tissue level.

Background Belimumab is approved for the treatment of systemic lupus erythematosus (SLE) since 2011. We investigated whether belimumab treatment impacts on levels of cytokines and autoantibodies of interest in SLE, as well as circulating immune complexes (ICs). Methods Longitudinally collected serum samples from 78 belimumab-treated SLE patients from the Karolinska, Skane and Linkoping University Hospitals were analysed. Serum cytokine levels and nuclear antigen autoantibody specificities were determined using addressable laser bead immunoassay, and circulating C1q-binding ICs were measured using enzyme-linked immunosorbent assay. Results In patients with detectable levels at baseline, serum IFN-α2 levels were lower at month 6 (median: 8.9; IQR: 1.5–54.9 pg/mL) versus baseline (median: 28.4; IQR: 20.9–100.3 pg/mL; P=0.043). IL-6 levels decreased from baseline (median: 7.1; IQR: 2.9–16.1 pg/mL) to month 6 (median: 0.5; IQR: 0.5–6.3 pg/mL; P=0.018) and throughout the 24-month follow-up. Levels of IL-10 (baseline median: 12.6; IQR: 2.8–29.7 pg/mL) showed more rapid decreases from month 3 (median: 1.8; IQR: 0.6–9.1 pg/mL; P=0.003). Levels of anti-dsDNA (P Conclusions In our cohort, belimumab treatment lowered IFN-α2, IL-6, IL-10 and circulating IC levels, as well as levels of multiple autoantibodies against nuclear components. Interestingly, anti-Sm antibody positivity was associated with favourable treatment response.

Background Patients with Systemic Lupus Erythematosus (SLE) are at increased risk of premature mortality due to myocardial infarction (MI). The underlying mechanisms are not fully understood. This study aims to generate new hypothesizes on these mechanisms through description of MI subtypes and locations and by identifying risk factors for MI. Methods We identified 35 SLE patients with and a first-time non-procedural MI (MI-SLE). We matched these 35 MI-SLE patients to 35 patients with MI but not SLE (MI-nonSLE) and 35 patients with SLE but not MI (nonMI-SLE) for gender, age and geographical location. Patients and controls were matched individually (1:1:1). Detailed retrospective medical file review was performed. Results Median age was 62 years and 89% were female in all groups. Prevalence of ST-elevation MI was similar in MI-SLE patients and MI-nonSLE patients (27% vs 36%; p=0.80). The left ventricle was the most commonly infarcted in both MI-SLE and MI-nonSLE - 77% vs 59% according to coronary angiography and 42% vs 55% according to echocardiography. The left ventricular ejection fraction was similar in MI-SLE and MI-nonSLE patients (p=0.62). MI with coronary atherosclerosis was trends wise more common in MI-SLE patients compared to MI-nonSLE patients (88% vs 66%; p=0.065). Previous cardiovascular disease (43%, 5.7%, 14%; p Conclusion Coronary atherosclerosis was present in a large majority of MI-SLE patients at the event of MI. In addition, coronary artery disease preceding MI was more prevalent in SLE patients than in the general population, indicating accelerated coronary atherosclerosis as a cause of increased MI prevalence in SLE. Among SLE patients, low albumin levels were a risk factor for MI.

Objective Rituximab-mediated late-onset neutropenia (LON) has been described in various diseases. We investigated its occurrence, consequences and contributing factors in patients with systemic lupus erythematosus (SLE). Methods Rituximab-treated patients from the Karolinska University Hospital ( n = 107) were surveyed. LON was defined as an absolute neutrophil count Results Thirty-two patients (29.9%) developed LON after a median time of 201.5 days. Thirteen patients were admitted to the hospital; 10 due to fever. Three patients developed critical conditions. BAFF levels increased from baseline (median: 0.62 ng/ml) to the post-treatment evaluation (median: 1.16 ng/ml; p 8). No association with neutropenia prior to rituximab treatment was documented. Conclusion Post-rituximab LON was a common complication. Although the phenomenon was predominantly self-limiting, several patients developed severe conditions. Distinct roles of BAFF and APRIL are implicated: BAFF may contribute to LON development, whereas high APRIL levels may be predictive. Rituximab-treated SLE patients should be monitored for neutrophil counts, fever and infections.

Objectives We investigated the cell adhesion molecules (CAMs) Vascular CAM 1 (VCAM-1) and Activated Leucocyte CAM (ALCAM) as urinary biomarkers in SLE patients with and without renal involvement. Methods Female SLE patients (n = 111) and non-SLE population-based controls (n = 99) were enrolled. We measured renal activity using the renal domain of the BILAG index and urine (U) and plasma (P) concentrations of soluble (s)VCAM 1 and U-sALCAM using ELISA. U-sCAM levels were next corrected by U-creatinine. Results U-sVCAM-1/creatinine and U-sALCAM/creatinine ratios were higher in SLE patients vs non-SLE controls (P Conclusion While high U-sVCAM-1 levels appear to reflect SLE disease activity, sALCAM might have particular importance in renal SLE. Both U-sVCAM-1 and U-sALCAM showed ability to distinguish SLE patients with active renal involvement from patients with quiescent or no prior nephritis. High U-sVCAM-1 levels may indicate patients at increased risk for long-term renal function loss.

Introduction Immune complexes are of importance in systemic lupus erythematosus pathogenesis, and autoantibodies are believed to participate in immune complex formation. Quantification of autoantibody levels in circulating IC might be of prognostic value. Methods A C1q-binding-eluting technique was applied to purify immune complexes from 55 belimumab-treated systemic lupus erythematosus patients during a 24-month follow-up. Autoantibodies in serum and in solubilized immune complexes were quantified using addressable laser bead immunoassay. We investigated whether levels of autoantibodies in immune complexes associate with disease activity and response to belimumab treatment. Results High baseline anti-double-stranded DNA and anti-histone levels in immune complexes associated with attainment of zero scores in clinical systemic lupus erythematosus disease activity index 2000 during the 24-month follow-up (p = 0.003 and p = 0.048, respectively). Low complement levels associated with high serum anti-double-stranded DNA and anti-ribosomal P levels (p = 0.003 and p = 0.008, respectively) and high anti-double-stranded DNA (p = 0.002) but not anti-ribosomal P levels in immune complexes. Anti-SSA/SSB serum levels were lower in patients attaining lupus low disease activity state at month 6; these associations were stronger for corresponding immune complex levels. Serum levels of most autoantibodies had declined at month 3, whereas autoantibody levels in immune complexes, except for anti-double-stranded DNA, showed a more gradual decline over 1–2 years. Serum anti-double-stranded DNA levels decreased in all patients irrespective of systemic lupus erythematosus disease activity index 2000=0 attainment, whereas immune complex levels decreased only in achievers. Conclusion Immune complex levels of autoantibodies against double-stranded DNA and the SSA/SSB complex show more specific associations with treatment outcome compared with serum levels in belimumab-treated systemic lupus erythematosus patients. Characterization of autoantibody content in circulating immune complexes could prove useful in treatment evaluation in systemic lupus erythematosus and other immune complex-associated diseases.

Background:Myocardial infarction (MI) is estimated to be 2- to 3-fold elevated in systemic lupus erythematosus (SLE) as compared to gender- and age-matched controls (1-2). Even though some risk factors have been purposed, mechanisms of increased MI incidence remains to be determined.Objectives:To explore underlying mechanisms, we compared MI characteristics and risk factors between SLE patients with MI (MI-SLE), MI patients without SLE (MI-nonSLE) and SLE patients without MI (nonMI-SLE).Methods:We performed retrospective medical file review including angiography and echocardiography reports in 34 MI-SLE patients, 34 MI-nonSLE patients and 34 nonMI-SLE patients – all individually matched for gender and age in a ratio of 1:1:1.Results:Median age was 61 years and 88% were females. MI-SLE patients had more coronary arteries involved (table 1; p=0.038), and ≥50% coronary atherosclerosis/occlusion at MI was numerically more common compared to MI-nonSLE controls (88% versus 66%; p=0.065). The left anterior descending artery was most frequently involved in both MI groups (73% versus 59%; p=0.11). Decreased (Conclusion:We demonstrate that non-procedural MIs in SLE are in 88% of cases associated with significant coronary atherosclerosis. Increased prevalence of CAD prior MI and higher number of coronary arteries involved at MI, suggest accelerated coronary atherosclerosis in SLE patients. This calls for attentive surveillance of CVD and early atheroprotective treatment in this patients group.References:[1]Hak AE et al. Systemic lupus erythematosus and the risk of cardiovascular disease: Results from the nurses’ health study. Arthritis and rheumatism 2009;61:1396-402.[2]Fischer LM et. Effect of rheumatoid arthritis or systemic lupus erythematosus on the risk of first-time acute myocardial infarction. The American journal of cardiology 2004;93:198-200.Table 1.MI characteristicsMI-SLENtotalMI-nonSLENtotalP-valueECG findingsNSTEMI23 (72%)3221 (66%)321.0 STEMIPresence of atherosclerosis9 (28%)3211 (34%)32 0-VD3 (12%)2610 (35%)290.065 MI-CAD (≥1-VD)Number of involved arteries23 (88%)2619 (66%)29 0-VD3 (12%)2610 (35%)290.038 1-VD13 (50%)269 (31%)29 ≥2-VD10 (39%)2610 (35%)29Involvement of specific arteriesLMCA3 (12%)260 (0%)290.50 LAD19 (73%)2617 (59%)290.11 RCA7 (27%)269 (31%)290.75 Cx6 (23%)266 (21%)291.0Left ventricular ejection fraction 13 (45%)2912 (36%)330.79 ≥50%16 (55%)2921 (64%)330-VD = 0-Vessel disease. 1-VD = 1-Vessel disease. 2-VD = 2-Vessel disease. Cx = Circumflex artery. LAD = Left anterior descending artery. LMCA = Left main coronary artery. MI-CAD = MI with coronary artery disease. NSTEMI = Non-ST-elevation MI. RCA = Right coronary artery. STEMI = ST-elevation MI.Disclosure of Interests:Isak Samuelsson: None declared, Ioannis Parodis Grant/research support from: The author declare that he has no conflict of interest related to this work, Iva Gunnarsson Grant/research support from: The author declare that she has no conflict of interest related to this work, Agneta Zickert: None declared, Claes Hofman-Bang: None declared, Håkan Wallén Grant/research support from: The author declare that he has no conflict of interest related to this work, Elisabet Svenungsson Grant/research support from: The author declare that she has no conflict of interest related to this work

Background:Complement plays a role in the Antiphospholipid Syndrome (APS). C4b Binding Protein (C4BP) is a complement inhibitor with anticoagulant function (1). It belongs to the same protein family as β2GPI, the main antigen in APS. Its main isoform is bound to protein S in the circulation. Levels of both protein S and C4BP are known to be reduced by warfarin treatment (2) as well as by aPL, directly and indirectly.Objectives:To investigate the levels of C4BP in primary (p) and secondary (s) APS, also considering warfarin treatment.Methods:The total amount of C4BP (C4BPt) was measured by using magnetic carboxylated microspheres which were coupled with a monoclonal antibody against the α-chain of human-C4BP to capture the antigen. To detect C4BPt the same antibody was used, biotinylated. The binding of biotinylated antibodies was detected by streptavidin-phycoerythrin and data were collected using a MAGPIX Multiplex Reader. Using independent t-test, we compared C4BP in 118 SLE patients with repeated positivity for Antiphospholipid antibodies (aPL) (39/118 on warfarin), 291 aPL negative SLE patients (16/291 on warfarin), 67 pAPS (33/67 on warfarin), and 322 controls (none on warfarin). We then performed an interaction and a mediation analysis (3) in the SLE group to study the impact of warfarin on C4BP levels: since warfarin is mostly prescribed to aPL+ patients, it is considered a mediator in the reducing effect of aPL on C4BP. Therefore we compared individuals exposed and non-exposed to the presence of aPL with or without the mediator warfarin and calculated the percentage of reduction in C4BP that could be attributed to aPL or warfarin.Results:Overall C4BP is 20% reduced in aPL+ patients (fig 1), independently of SLE, past thrombotic events and nephritis. Warfarin treated patients have lower levels of C4BP (fig 2). According to mediation analysis 11% of C4BP reduction is due to aPL and 9% to warfarin.Figure 1.C4BP in different subgroups (67 pAPS, 118 SLEaPL+, 291 SLEaPL-, 322 controls)Figure 2.C4BP in 67 pAPS patients, 33/67 on warfarinConclusion:Both aPL and warfarin decrease levels of C4BP, a complement and coagulation regulator. Reduction of this complement inhibitor could contribute to complement activation and thrombosis in APS. Our results raise new questions regarding the effects of warfarin treatment on complement and coagulation in APS.References:[1]Dahlbäck B. C4b-binding protein: a forgotten factor in thrombosis and hemostasis. Seminars in thrombosis and hemostasis 2011; 37(4): 355.[2]Zöller B, García de Frutos P, Dahlbäck B. Evaluation of the relationship between protein S and C4b-binding protein isoforms in hereditary protein S deficiency demonstrating type I and type III deficiencies to be phenotypic variants of the same genetic disease. Blood 1995; 85(12): 3524.[3]Vanderweele TJ, Vansteelandt S. Conceptual issues concerning mediation, interventions and composition. Statistics and Its Interface 2009; 2(4): 457-68.Disclaimer:AV is employed at the Swedish Medical Products Agency, the views expressed in this paper are the personal views of the authors and not necessarily the views of the Governement AgencyAcknowledgments:Thanks to the Biostatistics Core Facility, Karolinska UniversityDisclosure of Interests:None declared

Objectives: Recently, we demonstrated a negative impact of smoking on belimumab efficacy in patients with systemic lupus erythematosus (SLE). Here, we particularly investigated clinical effects of belimumab and a potential impact of smoking in mucocutaneous and articular SLE. Methods: We surveyed 62 SLE patients treated between 2011 and 2017. Evaluation included the mucocutaneous descriptors of SLEDAI-2K (rash, alopecia, mucosal ulcers; mcSLEDAI-2K), CLASI, the arthritis SLEDAI-2K descriptor (arSLEDAI-2K) and the 28-joint count. Results: mcSLEDAI-2K and CLASI activity decreased from baseline to month 6 and 12 (P < 0.001 for all). No worsening in CLASI damage was observed. Current or previous smokers displayed a higher probability of unchanged/worsened mcSLEDAI-2K compared to never smokers (OR: 6.4; 95% CI: 1.5–27.4; P = 0.012), also after adjustment for antimalarial agents. arSLEDAI-2K scores had decreased at month 6 (P < 0.001) and 12 (P < 0.001). Likewise, tender and swollen 28-joint counts had improved at month 6 (P = 0.010 and P < 0.001, respectively) and 12 (P = 0.001 for both). We observed no impact of smoking on belimumab efficacy in articular SLE. Conclusion: We observed a negative impact of smoking on the efficacy of belimumab in mucocutaneous SLE. In contrast, no impact of smoking on belimumab efficacy was seen in patients with articular manifestations. (Less)

Background Accumulating evidence supports an impaired health-related quality of life (HRQoL) in patients with systemic lupus erythematosus (SLE). The impact of modern therapeutic interventions on patients‘ perception of HRQoL has not been explored in depth. Objectives The aim of this study was to investigate the effects of two biologic treatments – belimumab and rituximab – on SLE patients’ HRQoL, fatigue and functional ability. Methods Patients with SLE from the Karolinska University Hospital treated with either belimumab (n=34) or rituximab (n=35) were included. Data were collected prospectively at treatment initiation and at months 3, 6, 12 and 24; these included the Medical Outcome Study short form-36 (SF-36) version 2, functional assessment of chronic illness therapy (FACIT)-Fatigue scale version 4, EuroQol research foundation 5-dimension (EQ-5D) health questionnaire, and Stanford health assessment questionnaire disability index (HAQ-DI). Results Substantial reductions compared to Swedish norms were observed across all SF-36 subscales at baseline (figure 1). SF-36 mental component summary scores were higher in patients who were on antimalarial agents (mean: 42.7; SD ±11.8; n=29) compared to patients who were not (mean: 34.0; SD ±14.7; n=32; p=0.019). Accordingly, patients who were on antimalarial agents performed better in SF-36 social functioning (mean: 63.7 versus 46.5; p=0.022) and mental health (mean: 68.7 versus 53.4; p=0.023) compared to patients who were not. Belimumab-treated patients reported gradual improvements in the SF-36 physical summary component (significant from month 12; p=0.023) and FACIT-Fatigue (significant by month 24; p=0.001), no changes in EQ-5D scores, and improvements in HAQ-DI by month 6 (p=0.014). Rituximab-treated patients reported rapid improvements in the SF-36 mental summary component and FACIT-Fatigue by month 3 (p=0.031 and p=0.007, respectively), which declined at month 12, as well as improvements in EQ-5D at month 6 (p=0.016) and HAQ-DI at month 3 (p=0.033), which were not maintained at later time points. Conclusions HRQoL was considerably impaired in SLE patients compared to population-based norms at baseline, and was not fully compensated during follow-up. Patients’ perceptions of HRQoL showed treatment-specific patterns over time, and could prove useful when evaluating the effects of biologics in SLE. Early evaluation of belimumab might underestimate improvements in HRQoL and fatigue. In severe SLE, antimalarial agents may have favourable effects on mental HRQoL aspects. Disclosure of Interest None declared

Objectives Composite criteria/indices are presently used to diagnose and monitor patients with systemic lupus erythematosus (SLE). Biomarkers for these purposes would be helpful in clinical practice. We therefore evaluated a large panel of cytokines and basic laboratory tests and investigated their performance as discriminators versus controls and as biomarkers of disease activity (DA). Methods We examined 437 patients with SLE, fulfilling American College of Rheumatology-82 criteria, and 322 matched controls. DA was assessed according to both SLE DA Index 2000 (SLEDAI-2K) and SLE Activity Measure (SLAM). British Isles Lupus Activity Group (BILAG) was used to assess renal DA. Additionally, 132 patients self-assessed their Global Disease Activity (PtGDA). Mesoscale Discovery 30-plex cytokine assay and routine blood chemistry was performed on fasting EDTA-plasma. Results Of 26 tested biomarkers, we identified TNF-α as the superior discriminator between patients with SLE and controls (median=4.5 pg/mL, IQR=3.1–6.2 vs median=2.3 pg/mL, IQR=2.0–2.8). The strongest correlations to SLEDAI-2K and SLAM were obtained with TNF-α (Spearman rho (ρ)=0.32 and ρ=0.34, respectively), partly driven by the nephritis subgroup, and with p-albumin (ρ=−0.33 and ρ=−0.31, respectively). P-albumin was decreased and TNF-α was increased in patients with kidney involvement (renal BILAG A/B vs C/D/E, p=4×10 –16 and p=6×10 –9 respectively). IP-10 was increased in patients with joint involvement (SLAM item 24≥2 vs ≤1, p=0.0005) but did not differ when comparing patients with active/inactive kidney involvement. The most powerful correlations to PtGDA was observed with p-albumin (ρ=−0.42), IL-6 (ρ=0.30) and TNF-α (ρ=0.29). Conclusion TNF-α and p-albumin both performed well as discriminators between patients with SLE and controls and as proxies for DA according to both rheumatologists’ and patients’ assessments. In particular, renal DA was well reflected by TNF-α. We propose that the TNF-α and p-albumin merit further investigations as clinically useful biomarkers in SLE. We also observed that the pattern of activated cytokines varies with organ involvement.

Background Interferons (IFN) play a major role in SLE pathogenesis.1 IFNs type I (predominately IFN-αs) are of major importance,2 but IFN type II (IFN-γ) and IFNs type III (λ) have also important roles.3,4 How the levels of circulating IFNs type I, type II and type III relate to each other, and if they associate with any particular SLE disease manifestations is not known. Objectives We investigated serum levels of type I, type II, and type III IFNs and explored how these measurements relate to each other and to specific organ manifestations in patients with SLE. Methods We studied 497 well-characterised SLE patients and 322 controls. Functional type I IFN-activity (IFN-activity) was measured by WISH cell assay. IFN-α and IFN-λ1 were measured by ELISA, and IFN-γ by MSD 30-plex assay. High IFN-activity/levels were defined as value over 3rd quartile of the measurement. Results SLE patients had higher levels of all investigated IFNs. IFN-activity correlated with IFN-α and IFN-γ. High functional IFN-activity associated with active SLE in most domains: weight loss, fatigue, fever, rash, lymphadenopathy, arthritis and nephritis. The IFN-γ high group had active disease with higher rates of nephritis, arthritis, leuko-, lymphopenia and Sm, SmRNP, RNP68, Ro52 and Ro60 autoantibodies. A higher proportion of the IFN-α high group had active rash, lymphadenopathy, Ro52 and La autoantibodies, while rates of antiphospholipid antibodies/syndrome, vascular events and renal affection were lower. High IFN-λ1 associated with anti-nucleosome autoantibodies and lymphopenia. Conclusions High type I IFN functional activity is associated with active SLE in the majority domains. A severe SLE phenotype, including active nephritis, arthritis and anti-Sm/SmRNP autoantibodies is associated with high IFN-γ, while rash and a benign cardiovascular profile are linked to high serum IFN-α. Isolated increase in IFN-λ1 is only coupled to lymphopenia and antinucleosome antibodies. Our findings demonstrate that several IFNs can be elevated at the same time in SLE and the importance of IFN-γ has so far been underscored. Sub-setting of SLE patients might be important when planning future clinical trials. References [1] Niewold TB, Hua J, Lehman TJA, et al. High serum IFN-alpha activity is a heritable risk factor for systemic lupus erythematosus. Genes Immun2007;8:492–502. doi:10.1038/sj.gene.6364408 [2] Bengtsson AA, Sturfelt G, Truedsson L, et al. Activation of type I interferon system in systemic lupus erythematosus correlates with disease activity but not with antiretroviral antibodies. Lupus2000;9:664–71. [3] Oke V, Brauner S, Larsson A, et al. IFN-λ1 with Th17 axis cytokines and IFN-α define different subsets in systemic lupus erythematosus (SLE). Arthritis Res Ther2017;19:139. doi:10.1186/s13075-017-1344-7 [4] Machold KP, Smolen JS. Interferon-gamma induced exacerbation of systemic lupus erythematosus. J Rheumatol1990;17:831–2. Acknowledgements We are grateful to Susanna Eketjall, Eva Jemseby, Johanna Gustafsson, Marie Wahren-Herlenius, Susanna Brauner, Ola Borjesson, Marika Kvarnstrom, Susanne Pettersson, Sonia Moller, Jill Gustafsson for help with different parts of the project. Disclosure of Interest None declared

Background Sjogren´s syndrome occurs in isolation (primary Sjogren´s syndrome, pSS), but it is also often secondary (sSS) to, and sometimes difficult to delineate from systemic lupus erythematosus (SLE). Consequently there is a need to investigate similarities and differences between SLE patients with (SLE-sSS) and without sSS (SLE-noSS). Objective To investigate the occurrence of sSS in a large cohort of SLE patients and to explore clinical and laboratory characteristics associated with SLE-sSS as compared to SLE-noSS and controls. Methods We included 504 consecutive SLE patients and 322 population controls, matched for age and gender. All patients fulfilled the 1982 revised ACR criteria for SLE. SLE-sSS was defined according to the American-European consensus criteria (AECC). Subjective and objective quantifications of sicca symptoms were recorded. All underwent a thorough clinical investigation. SLE-associated autoantibodies, (ANA screening by BioPlex 2200 system, Bio-Rad) and Rheumatoid factor (Rf, Phadia Immunocap 250) were determined, Routine laboratory workup and a panel of cytokines (MSD 30-plex cytokine assays, performed on samples from 433 consecutive SLE patients and 319 controls) were measured. Results SLE-sSS, occurred in 23% of the SLE patients. Compared to SLE-noSS the SLE-sSS group was older, both at inclusion (55 vs 43 years, p Conclusion Frequency of SLE-sSS increases with age and affects roughly ¼ of SLE patients. Nephritis was less common while leucopenia and peripheral neuropathy were more common. We report higher levels of six pro-inflammatory. These findings demonstrate that, though often regarded as a milder version of SLE, patients with SLE-sSS are characterised by a state of chronic systemic inflammation.

Background Serum induced IFN gene expression (IFN-score) is considered a golden standard to assess IFN activity in SLE. So far, IFN-scores have not been compared to serum levels of type I, II and III IFNs. Aim To investigate how IFN-scores and SLE manifestations relate to serum levels of IFNs type I (alphas), II (gamma) and III (lambda 1). Methods 461 SLE patients and 322 controls were included. IFN-score was measured by WISH cell assay. INF-alphas and IFN-lambda1 were measured by ELISA. IFN-gamma was measured by MSD 30-plex assay. Results SLE patients had higher IFN-scores and higher levels of IFN-alphas, IFN-gamma and IFN-lambda1 (p 3 rd quartile) of each IFN/IFN-score. The group with high IFN-scores had higher disease activity (SLAM, SLEDAI): weight loss (41%), fatigue (33%), fever (39%), rash (44%), lymphadenopathy (45%), arthritis (40%), nephritis (55%) (p The characteristics of IFN-gamma high group included higher disease activity (SLAM, SLEDAI), and specifically: active nephritis (52%), lymphadenopathy (40%), arthritis (42%), lymphopenia (37%), anaemia (35%) and positivity for Sm (41%), SmRNP (36%) and RNP68 (45%), Ro52 (35%) and Ro60 (33%) (p The common features of IFN-alpha high group included younger age, shorter disease duration, active rash (34%), lymphadenopathy (43%), Ro52 (38%) and La (43%) (p=0.01). Presence of aPL abs and previous vascular events were lower and renal affection was uncommon (p In general, high IFN-scores reflected SLE manifestations that could be further stratified by high IFN-gamma levels and to a lesser extent by high IFN-alpha. High IFN-lambda1 did not define any phenotype of active SLE, except presence of anti-nucleosome abs. Conclusion We demonstrate that high IFN-score associate more strongly with type II rather than type I IFNs. Importantly, major manifestations of SLE: active nephritis and arthritis, and also anti-Sm/SmRNP antibodies associate with IFN-gamma; while rash associate with IFN-alpha. Our findings are of major importance while tailoring clinical trials with anti-IFN therapies and demonstrate that importance of IFN-gamma has so far been underscored.

SLE is a heterogeneous disease including diverging clinical symptoms, autoantibodies and genetic susceptibility. Hitherto unrecognised patterns may define sub-phenotypes with different pathogenesis and specific treatment needs. Based on autoantibody profile we therefore investigated phenotypic clusters and explored cluster associations with clinical manifestations and one of the most important genetic risk factors for SLE, HLA-DRB1 alleles. 908 SLE Caucasian patients and 3654 age- gender- and ethnicity-matched healthy controls (HC) were included. We determined the occurrence of 13 autoantibodies: dsDNA, nucleosomes, ribosomal P, RNP68, RNPA, Sm, Sm/RNP, SSA52, SSA60, SSB, aCL-IgG/IgM and aB2GP1. HLA-DRB1 typing was performed by sequence-specific primer polymerase chain reaction assay. Cluster analysis was done using Gower distance matrix, followed by partition around medoids cluster calculation and Silhouette metric for number of clusters validation. Chi-square test, odds ratios (OR), 95% confidence intervals and false discovery rate p value (p) were calculated for the association tests. Four clusters were defined based on autoantibody occurrence. 29%, dominated by anti–SSA52/60/SSB positivity is strongly associated with HLA–DRB1*03 when compared to HC (4.1[3.4–4.9] p=6.4E–56) and other clusters (OCs) (2.9[93.3–3.6] p=1.1E–19). Discoid lesions were more common vs OCs (1.8[1.3–2.6] p=0.02). 29%, dominated by anti–SmRNP/Sm/DNA/RNPA/RNP68/nucleosome, was specifically associated with HLA–DRB1*15 when compared to HC (1.7[1.6–2.1] p=5.7E–6) and other clusters (1.5[1.1–1.9] p=0.01). Nephritis was common vs OCs (1.9[1.4–2.7) p=2.E–03) 24%, dominated by anti–B2GP1/aCL–IgG/IgM, was associated with HLA–DRB1*04 when compared with other clusters (1.8[1.4–2.4] p=2E–4). More thrombotic events vs OCs were observed in this group (1.84 [1.3–2.6] p=0.01) 18% was negative for the 13 tested autoantibodies and was not associated with any specific HLA–DRB1 alleles and it was not associated as risk factor for any of the evaluated clinical manifestations. We demonstrate that immune-phenotypes/clusters in SLE can fit into a frame of HLA-DRB1 alleles and that the overall association between SLE and HLA-DRB1*03 and HLA-DRB1*15 seems to be driven mainly by clusters 1 and 2, respectively. We also confirm previous observations that autoantibody clusters associate with clinical symptoms. We believe that these results could be used to redefine SLE, determine predictive biomarkers and inclusion criteria for clinical trials.

Background Belimumab is a biologic agent approved for the treatment of systemic lupus erythematosus (SLE). Recently, we demonstrated decreasing SLE activity during belimumab treatment in patients from three Swedish clinical settings. In the present study, we aimed to investigate the effects of belimumab on mucocutaneous and articular SLE in relation to smoking status. Methods Sixty-two patients with active SLE treated with belimumab between 2011 and 2017 were enrolled. We assessed the mucocutaneous disease using the mucocutaneous SLEDAI-2K and the cutaneous lupus erythematous disease area and severity index (CLASI). Musculoskeletal activity was evaluated by the arthritis SLEDAI-2K descriptor and the 28-joint count. Results At baseline, 44/62 (71.0%) patients had a mucocutaneous SLEDAI-2K score 2 or more (mean mucocutaneous SLEDAI-2K: 2.3; range 0–6; n=62). The mean baseline CLASI activity was score: 8.4 (range: 0–39; n=33). We observed decreased mucocutaneous SLEDAI-2K scores at month 6 (p Conclusion In line with previous reports, belimumab treatment was effective in limiting mucocutaneous and articular symptoms in patients with SLE. A history of past or current smoking was found to reduce the efficacy of belimumab in mucocutaneous manifestations. Further survey on the impact of smoking on the efficacy of belimumab at a mechanistic level is merited.

Background and aims There is convincing evidence that adaptive immune responses affect the development of atherosclerosis and thrombosis and several autoimmune diseases are associated with increased cardiovascular risk. However, our understanding of the underlying mechanisms remains limited. We investigated how biomarkers reflecting four aspects of autoimmunity: apoptosis, inflammation, tissue degradation and repair, associate with cardiovascular disease (CVD) in subjects with systemic lupus erythematosus (SLE). Methods We investigated 484 well-characterized SLE patients, 69 of whom had CVD (coronary artery disease, cerebrovascular disease or peripheral artery disease), and 253 controls. Occurrence of carotid plaques was investigated with ultrasound. Plasma levels of biomarkers reflecting apoptosis (Fas, TNF receptor 1, TRAIL receptor 2), inflammation (IL-6, IL-8, monocyte chemotactic protein-1), tissue degradation (matrix metalloproteinase (MMP)-1, MMP-3, MMP-7), and tissue repair (platelet-derived growth factor, epidermal growth factor and stem cell factor) were analyzed by Proximity Extension Assay. Results Subjects with SLE had markedly elevated plasma levels of biomarkers reflecting apoptosis, inflammation and tissue degradation as compared to controls. SLE patients with CVD had higher levels of Fas, TNF receptor 1, TRAIL receptor 2, MMP-1 and -7 than those without CVD. The same associations were found for the presence of a carotid plaque. When controlling for the factors included in the Framingham risk score, all biomarkers except MMP-1 remained associated with the presence of a carotid plaque, while only TRAIL receptor 2 levels remained significantly associated with CVD. Conclusions Our findings argue that the cardiovascular risk in SLE is associated with increased cell death by apoptosis and tissue degradation.

High Anti-Dsdna Content in Sle Immune Complexes is associated with Clinical Remission Following Belimumab Treatment

Background Sjogren9s syndrome occurs in isolation (primary Sjogren9s syndrome, pSS), but it is also often secondary (sSS) to, and sometimes difficult to delineate from, other rheumatic diseases, in particular from systemic lupus erythematosus (SLE). Consequently there is a need to investigate similarities and differences between SLE patients with (SLE-sSS) and without sSS (SLE-noSS). Objectives To investigate the occurrence of sSS in a large cohort of SLE patients and to explore clinical and laboratory characteristics associated with SLE-sSS as compared to SLE-noSS and controls. Methods We included 504 consecutive SLE patients and 322 population controls, individually matched for age and gender to the first patients. All patients fulfilled the 1982 revised ACR criteria for SLE. SLE-sSS was defined according to the American-European consensus criteria (AECC). Accordingly, subjective and objective quantifications of sicca symptoms were recorded on all subjects. All underwent a thorough clinical investigation. SLE-associated autoantibodies, (ANA screening by BioPlex 2200 system, Bio-Rad) and Rheumatoid factor (RF, Phadia Immunocap 250) were determined with standardized methods for all subjects, Routine laboratory workup and a panel of cytokines (MSD 30-plex cytokine assays, performed on samples from 433 consecutive SLE patients and 319 controls) were measured on fasting blood samples. Results SLE-sSS, as defined by AECC, occurred in 23% of the SLE patients. Compared to SLE-noSS the SLE-sSS group was older, both at inclusion (55 vs 43yrs, p Conclusions Through strictly applying the AECC criteria we report that the frequency of SLE-sSS increases with age and affects roughly ¼ of SLE patients. Nephritis was less common while leucopenia and peripheral neuropathy were more common among SLE-sSS patients. In addition to excess of well-known SS-associated autoantibodies we report higher levels of six pro-inflammatory cytokines in SLE-sSS as compared to SLE-noSS. These findings demonstrate that, though often regarded as a milder version of SLE, patients with SLE-sSS are characterized by a state of chronic systemic inflammation. Acknowledgements Susanna Eketjall at Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Integrated Cardio Metabolic Centre (ICMC), Karolinska Institutet, Huddinge, Sweden Disclosure of Interest None declared

Background and aims Belimumab is the first biologic drug approved for Systemic Lupus Erythematosus (SLE). Here, we aimed to investigate the effects of belimumab on clinical and serologic outcomes, and sought to identify predictors of treatment response in three Swedish real-life settings. Methods Fifty-eight patients were enrolled at initiation of belimumab and followed longitudinally for up to 53 months. Surveillance outcomes included the SLE Disease Activity Index 2000 (SLEDAI-2K), 100 mm Visual Analogue Scales for Physician’s Global Assessment (PGA), fatigue, pain and general health, and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). Assessment of treatment response included the SLE responder index (SRI). B lymphocyte stimulator (BLyS) levels were determined using ELISA. Results SLEDAI-2K (median baseline score: 8.0; IQR: 4.0–13.8), PGA and corticosteroid use decreased during therapy, and patients reported improvements on fatigue, pain, and general health (p 1 showed decreased probability and prolonged time to attain SRI response (HR: 0.449; 95% CI: 0.208–0.967), as did current smokers compared with non-smokers (HR: 0.103; 95% CI: 0.025–0.427). In contrast, baseline BLyS levels≥1.2 ng/mL predicted increased probability and shorter time to attain SRI response (HR: 2.566; 95% CI: 1.222–5.387). Conclusions Disease activity and corticosteroid usage decreased, patient-reported outcomes improved, and no significant organ damage was accrued during follow-up. Smoking and organ damage predicted reduced treatment efficacy. These findings might contribute to a better selection of patients who are likely to benefit from belimumab.

Background and aims Interferon (IFN)-αs are pivotal in systemic lupus erythematosus (SLE), and type III IFNs (IFN-λs) were recently also associated with SLE. We investigated levels of IFN-α and IFN-λ1, and related cytokines in SLE patients and controls. Methods We included 261 SLE patients and 261 population controls. All were examined and assessed for current organ manifestations and disease activity/damage using SLAM, SLEDAI and ACR/SDI scales. Levels of IFN-λ1, IFN-α, IL-17A, IL-23 and IP-10 were measured by ELISA. Results IFN-λ1 and IFN-α were detected in 29% and 44% of patients respectively, but their levels did not correlate. High serum levels of IFN-λ1 were positively associated with anti-nucleosome antibodies and lymphopenia, but negatively with musculoskeletal damage. Positive correlations between levels of IFN-λ1, IL-17A and IL-23 were observed. Patients with high levels of these three cytokines had more disease damage, especially renal. High levels of IFN-α were associated with mucocutaneous disease, leukopenia, low complement, Ro/SSA and La/SSB, whereas vascular events and antiphospholipid antibodies (aPL) were uncommon. We identified two subgroups with high disease activity: one double IFN-λ1 and IFN-α high and another IP-10 high. The former had more neuropsychiatric manifestations, while the latter had more arthritis. Conclusions Measurements of circulating IFN-λ1 and IFN-α define SLE patients with different characteristics. Levels of IFN-λ1 correlate with Th17 cytokines and identify a subgroup with more damage. Disease activity is associated with either upregulation of both type I and III IFNs, or independently with IP-10. Our findings could be of major importance when tailoring therapy for SLE patients with agents targeting IFN-pathways.

Background and aims Belimumab is a monoclonal antibody that inhibits soluble B lymphocyte stimulator (BLyS, also known as BAFF), approved for the treatment of systemic lupus erythematosus (SLE). Here, we sought to identify B cell alterations during belimumab treatment. Methods Twenty-three SLE patients treated with belimumab were enrolled. Peripheral blood mononuclear cells were collected and cryopreserved at treatment initiation and at regular follow-up visits for up to 3 years. The samples were simultaneously assayed using mass cytometry. Cell counts were adjusted for total lymphocyte counts. Results CD20 + B cells decreased over time (p + CD20 + IgD + IgM + CD27 - ) and age-associated B cells (CD19 + CD20 + CD11c + CD21 - ) already at the first follow-up visit (month 3), followed by a continuous decrease (p + CD20 + IgD - CD27 - ) declined significantly first at month 6 (p=0.033) and pre-switching B cells (CD19 + CD20 + IgD + CD27 + ) showed a trend towards a decrease (p=0.052). Plasma cells (CD138 + CD38 + CD27 + CD19 + CD3e - CD20 - ) and switched memory B cells (CD19 + CD20 + CD27 + IgD - ) remained stable during the study period, as did T cells and monocytes (p>0.2). Despite continuously decreasing SLE Disease Activity Index, immunological changes correlated with clinical improvements only during early time points (month 0–3). Interestingly, high baseline B cell counts were predictive of non-attaining Lupus Low Disease Activity State at month 24 (area under the ROC-curve: 0.95). Conclusions B cell alterations betided in two distinct phases, a rapid early and a gradual late phase. Late clinical improvements might reflect preceding immunological changes, implying that early treatment evaluation and discontinuation might underestimate delayed improvements reflecting the late B cell changes.