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Objective. To elucidate whether clinical features and the weighted genetic risk score (wGRS) were associated with the presence of lupus nephritis (LN). Methods. We retrospectively divided patients with systemic lupus erythematosus (SLE, n=1,078) into biopsy-proven LN (n=507) and non-LN groups (non-LN, n=571). Baseline clinical features, serologic markers, and the wGRS were collected. The wGRS was calculated from 112 non-human leukocyte antigen (non-HLA) loci and HLA-DRβ1 amino acid haplotypes for SLE. Associations among clinical features, wGRS, and the presence of LN were identified. Results. In the multivariate analysis, patients with LN were younger at diagnosis (odds ratio [OR]=0.97, p＜0.001), had more pleuritis (OR=2.44, p＜0.001) and pericarditis (OR=1.62, p=0.029), had a higher detection rate of anti-double stranded deoxyribonucleic acid (anti-dsDNA antibodies, OR=2.22, p＜0.001), anti-Smith antibodies (anti-Sm antibodies, OR=1.70, p=0.002), low level of complement (OR=1.37, p=0.043) and absence of antiphospholipid antibodies (aPL antibodies, OR=1.60, p=0.002), and had higher wGRS (OR=1.16, p=0.012). Mediation analysis suggested that anti-Sm antibodies and low complement could be mediators in the relationship between high wGRS and the presence of LN. Conclusion. Onset age, pleuritis, pericarditis, several serologic markers, and wGRS were associated with the presence of LN. Anti-Sm antibodies and low complement appeared to mediate the indirect relationship between wGRS and the presence of LN. (J Rheum Dis 2021;28:150-158)

Background Atypical haemolytic uraemic syndrome (aHUS) is a rare systemic syndrome characterized by non-immune haemolytic anaemia, thrombocytopenia, and kidney injury. In most cases, alternative complement pathway dysregulation is the identifying cause. Recently, other genetic causes have been identified, including a mutation in the diacylglycerol kinase epsilon (DGKE) gene, which theoretically affect the coagulation pathway and does not affect the complement pathway. Data about the management of these patients are limited. Ideal management and definitive treatment protocols have not yet been established. Case presentation A three-year-old boy presented with features of atypical haemolytic uraemic syndrome (aHUS) and low complement C3. He was presumed to have complement-mediated aHUS and was managed empirically with eculizumab. Two weeks after starting eculizumab, his haemoglobin levels, platelet count, and complement C3 level normalized but he continued to have non-nephrotic range proteinuria. His genetic testing revealed a homozygous DGKE mutation, with no other mutation detected. Six months after presentation, the patient was still in remission with no features of aHUS, a trial of weaning eculizumab by increasing dose interval was followed by nephrotic range proteinuria and severe oedema. His proteinuria improved and his oedema resolved after resuming his recommended eculizumab dose. Conclusions DGKE gene mutation can lead to aHUS with theoretically no complement dysregulation. However, some patients with this mutation show alternative complement pathway activation. This case report describes a patient with aHUS due to a DGKE gene mutation and low C3 levels who responded to eculizumab, adding to the previously reported cases of patients with DGKE gene mutations who had complete remission with no relapse with C5 blockers and/or plasma exchange. A randomized controlled study on patients with DGKE mutations might be beneficial in understanding the disease and generating a management protocol.

Introduction Atypical hemolytic uremic syndrome (aHUS) is characterized by hemolytic anemia, thrombocytopenia, and acute kidney injury. Uncontrolled activation of the complement system induced by single or combined complement gene mutations is one of the mechanisms leading to the pathogenesis of aHUS. Case presentation We report a case of a 26-year-old female with a C3 heterozygous gene mutation (p.Asn153Asn). The patient was found to have low complement H factor (CFH) but normal levels of anti-CFH autoantibody. She was treated primarily with plasma exchange and plasma infusion. The patient did not relapse during a 1-year follow-up. Conclusion This is the first case of a novel C3 mutation (p.Asn153Asn) in a patient with aHUS. Further studies are needed to confirm the association between this mutation and the CFH level.

Background In SLE, low complement is an important serological manifestation. Recent classification criteria include hypocomplementemia and one gives additional weight if both C3 and C4 are low. We evaluated patients with a history of, and those with persistently, low complement. As complement activation occurs in the antiphospholipid antibody syndrome, an analysis was also performed on those with positive antiphospholipid antibodies to evaluate thrombotic outcomes. Methods In a longitudinal SLE cohort, organ manifestations, damage, C3, C4 and antiphospholipid antibodies were assessed quarterly. Using univariate and multivariate methods we compared those with and without a history of low C3, low C4 and both. We evaluated those who had a history of low complement at any time point, and those who had persistent hypocomplementemia. Further analysis considered thrombotic outcomes in patients with positive antiphospholipid antibodies and a history of low complement. Results 2399 patients were evaluated. Fifty-five percent had a history of low C3 and 47% low C4; 83 (4%) had persistently low C3 and 65 (3.2%) had persistently low C4. Hematological, renal and serological abnormalities associated with a history of low C3 but not low C4. With anticardiolipin antibodies, a history of hypocomplementemia (both C3 and C4 low) associated with stroke and deep venous thrombosis. Conclusion Low C4 was a weak marker in terms of the associated clinical and serological manifestations. Low C3 associated with renal involvement and poor renal outcomes. A history of both low C3 and C4 associated with stroke in the presence of lupus anticoagulant or anticardiolipin antibodies, and low C4 with digital gangrene (with lupus anticoagulant).

Objective To demonstrate the effect of preconceptional complement levels on perinatal outcomes of pregnancies with autoimmune disorders. Methods Pregnant women with autoimmune disorders (autoimmune disease and/or autoimmune antibody positivity) who were screened for complement levels (C3 and C4) prior to their pregnancies were enrolled in a special antenatal care program. These patients were administered low-dose low-molecular-weight heparin (enoxaparine, 1 × 2000 Anti-XA IU/0.2 mL/day), low-dose salysilic acid (100 mg/day) and low-dose corticosteroid (methylprednisolone, 1 × 4 mg/day orally) as soon as their pregnancies were confirmed according to the institutional protocol. We have compared hypo- and normocomplement pregnancies with autoimmune disorders in terms of their obstetric and perinatal outcomes. We have also used Beksac Obstetric Index (BOI) which is "[living child + (π/10)]/gravidity" for the comparison of their previous obstetric histories. Results Obstetric and neonatal outcomes showed no significant difference between hypocomplement patients (n= 38) and control group (n= 157) (p> 0.05). "Composite obstetric and perinatal adverse outcome" rates were 26.2% and 27.3% in study and control groups, respectively (p> 0.05). BOI was significantly lower in hypocomplement patients (p: 0.002). Then, we have classified hypocomplement patients into 3 subgroups according to the type of complement (C3, C4 or both). Comparison inbetween these groups revealed no statistical significance in any of the analyzed parameters (p> 0.05). Conclusion Low complement levels in pregnant women with autoimmune disorders may be associated with gestational problems and poor obstetric history. Immunomodulatory treatment modalities such as ours may be beneficial for improving the obstetric and neonatal outcomes.

ObjectiveTo assess the appropriateness of expanded serological activity eligibility criteria for belimumab use in the UK systemic lupus erythematosus (SLE) population (and possibly other countries), which includes patients with either anti-double-stranded DNA (anti-dsDNA) positivity or hypocomplementaemia rather than both criteria.MethodsThis post-hoc analysis used data from three randomised, double-blind, placebo-controlled phase III belimumab trials: BLISS-52 (BEL110752; NCT00424476), BLISS-76 (BEL110751; NCT00410384) and BLISS-SC (BEL112341; NCT01484496). Patients with SLE were stratified by high disease activity (HDA): HDA1, Safety of Estrogens in Lupus Erythematosus National Assessment-SLE Disease Activity Index (SELENA-SLEDAI) score ≥10, low complement and positive anti-dsDNA; and HDA2, SELENA-SLEDAI ≥10 and either low complement or positive anti-dsDNA.ResultsThis analysis included 660 HDA1 patients (n=396 on intravenous treatment; n=264 on subcutaneous treatment) and 969 HDA2 patients (n=532 on intravenous treatment; n=437 on subcutaneous treatment). Significant improvements were observed at week 52 with belimumab versus placebo, irrespective of subgroups or drug formulations, in SLE Responder Index (SRI) 4 response (OR (95% CI): HDA1 intravenous 2.7 (1.8 to 4.1); HDA2 intravenous 2.3 (1.61 to 3.26); HDA1 subcutaneous 2.2 (1.22 to 3.85); HDA2 subcutaneous 1.8 (1.17 to 2.74)); proportion of patients achieving ≥4-point reduction in SELENA-SLEDAI score (OR (95% CI): HDA1 intravenous 2.6 (1.7 to 3.9); HDA2 intravenous 2.1 (1.49 to 3.03); HDA1 subcutaneous 2.3 (1.30 to 4.14); HDA2 subcutaneous 1.9 (1.21 to 2.84)); patients with no worsening in Physician Global Assessment (OR (95% CI): HDA1 intravenous 2.0 (1.3 to 3.1); HDA2 intravenous 1.7 (1.17 to 2.45); HDA1 subcutaneous 2.3 (1.18 to 4.40); HDA2 subcutaneous 1.8 (1.11 to 2.92)); and risk of severe flares (HR (95% CI): HDA1 intravenous 0.6 (0.37 to 0.81); HDA2 intravenous 0.6 (0.43 to 0.86); HDA1 subcutaneous 0.52 (0.30 to 0.92); HDA2 subcutaneous 0.59 (0.37 to 0.94)).ConclusionBroadening the HDA population to include either low complement or positive anti-dsDNA, rather than both, would enable more UK patients to receive SLE treatment and experience improved clinical outcomes.

Purpose To describe and compare the clinical features of patients with first-episode neuromyelitis optica spectrum disorder (NMOSD) in a normal complement C4 group and a low complement C4 group, and explore the mechanism by which low complement C4 affects the clinical features of patients with NMOSD. Patients and Methods We retrospectively analyzed clinical data of 169 aquaporin-4 (AQP4) antibody positive patients with NMOSD from the First Affiliated Hospital of Zhengzhou University from December 2013 to March 2021. Prior to treatment, the blood was drawn for detection, and the patients underwent a 3.0 Tesla MRI examination. A low complement C4 level was defined as a serum complement C4 level Results Among the 169 AQP4 antibody positive patients, 54 were low-complement C4 patients and 115 were normal. There were no significant differences in the demographics, clinical manifestations, treatment options, or admission Expanded Disability Status Scale (EDSS) score between two groups (P > 0.05). The median of discharged EDSS was the same (4 vs 4), but the difference between the two was statistically significant (P = 0.019). Compared with the normal complement C4 group, the blood uric acid level (225 vs 179; P = 0.001) and the C3 level (1.06 vs 0.87, P = 0.000) of the low complement C4 group were significantly lower. The incidence of brainstem lesions in patients with low complement C4 was higher (53.7% vs 33%, P = 0.01). Conclusion The treatment effect of the first-episode AQP4 antibody positive NMOSD low complement C4 group was poor, the blood-brain barrier was more severely damaged, and the disease changes were likely to involve the brainstem.

Various thermosensitive liposome (TSL) formulations have been described to date and it is currently unclear which are optimal for solid tumor treatment. Sufficient circulation half-life is important and most liposomes obtain this by polyethylene glycol (PEG) surface modification. 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG2) has been described as a promising alternative which increases TSL circulation half-life and facilitates rapid drug release under mild hyperthermia at 20–30 mol%. The present work describes an investigation of the DPPG2-TSL protein corona, blood cell interactions, complement activation in human plasma/blood and hypersensitivity reactions in rats. Furthermore, accelerated blood clearance (ABC) was investigated to obtain a complete assessment of DPPG2-TSL interactions with components of the blood and identify drivers for circulation half-life. A higher mol% DPPG2 increased Apolipoprotein E (ApoE) adsorption and decreased complement activation and granulocyte interaction in vitro. In contrast to PEG-TSL, DPPG2-TSL showed no ABC effect. In vivo hypersensitivity assessment by eicosanoid measurements, platelet and lymphocyte counting resembled the results of in vitro complement activation assays although here all DPPG2-TSL formulations induced hypersensitive responses upon i.v. administration. Prolonged circulation half-life of DPPG2-TSL may be ApoE-induced and the absent ABC effect demonstrates an advantage over PEG-TSL. Low complement activation in human plasma and blood for 20–30 mol% DPPG2-TSL presents a unique formulation attribute with the potential to strengthen clinical evaluation.

The interesting report by Karagianni P et al on the finding of increased DNA methylation of H19 locus imprinting control region in saliva samples of Sjogren’s syndrome patients correlating with low complement C4 levels, may offer insights into how C4 level may be regulated in serpinopathies such as C1-inhibitor deficiency. An undetectable or low C4 level in patients with severe angioedema is a feature of C1-inhibitor deficiency (hereditary angioedema (HAE) type I with low to absent function and antigenic levels; HAE type II with point mutations in SERPING1 gene that affect the reactive centre loop affecting protein function only). However, C4 levels do not always clinically correlate with disease activity, and up to 6% patients do not have known mutations in the SERPING1 gene.

Background: While many humanized monoclonal antibodies utilize complement-dependent cytotoxicity, the complement depleting effects of these antibodies and the impact of complement replacement on treatment response are not well-described. Methods: We conducted a phase 2 trial involving patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Patients were treated with ofatumumab with fresh frozen plasma (FFP) used as a source of complement replacement. The primary endpoint was objective response rate. Correlative endpoints included complement levels (C3 and C4) and complement activity (CH50) which was drawn at baseline and after ofatumumab with FFP administration. Results: Among 12 enrolled patients, overall response rate was 83% with two patients (17%) achieving a complete response. While only two (17%) patients had low complement activity at baseline, eight (67%) developed low levels of complement activity after ofatumumab treatment with FFP replacement. The magnitude of complement depletion did not correlate with response. Adverse events were minimal. The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Conclusions: The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Complement replacement should be studied further as a minimally toxic approach to improve efficacy of monoclonal antibody-based regimens. J Hematol. 2020;9(3):79-83 doi: https://doi.org/10.14740/jh721

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect almost any organ in the body. It usually runs a chronic course with systemic inflammation, and age at diagnosis varies from 15 to 44 years. Laboratory reports often show high anti-nuclear antibody (ANA) levels, increased anti-double-stranded deoxyribonucleic acid (anti-dsDNA) levels, and low complement levels. 'Lupus flare' is a term used for an acute exacerbation of previously existing SLE. It usually manifests as an acute worsening of clinical signs and symptoms, along with an abrupt change in typical laboratory values. Triggers for a lupus flare include viral or bacterial infections, acute stress, and various environmental factors such as ultraviolet (UV) light. Ciprofloxacin is a broad-spectrum fluoroquinolone antibiotic used for various bacterial infections. On rare occasions, ciprofloxacin can cause adverse effects in the body, which may resemble an acute flare of SLE symptoms in patients with previously controlled disease. We have presented such a case of ciprofloxacin-induced reactions mimicking a lupus flare in an SLE patient.

We aimed at establishing a sensitive and robust assay for estimation of systemic complement activation at complement component C3 level in mouse and human plasma samples. In order to capture the activation products iC3b and C3dg in a specific and physiological relevant manner we utilized a construct consisting of the iC3b/C3dg-binding site of human complement receptor 2 (CR2) attached to an Fc-part of mouse IgG. This construct binds C3dg and iC3b from both mice and humans. We purified the CR2-IgG construct from mouse B myeloma cell line supernatants, J558L-CR2-IgG, by protein G affinity chromatography. The CR2-IgG construct was used for capturing C3 fragments in microtiter wells and an anti-mouse or an anti-human-C3 antibody was used for detection of bound C3 fragments. Initially we tested the specificity of the assays with the use of purified C3 fragments. Further, with the use of the CR2-based assay, we measured an up to three-fold higher signal in activated mouse serum as compared to non-activated mouse serum, whereas activated serum from a C3 knock-out mouse gave no signal. We tested in vivo generated samples from a mouse experiment; complement activation was induced by injecting cobra venom factor or heat aggregated IgG into C57bl6 mice, followed by withdrawal of EDTA blood samples at different time points and measurement of iC3b/C3dg. We observed a clear time-dependent distinction in signals between samples with expected high and low complement activation. Furthermore, with the use of the assay for human C3 fragments, we observed that patients with systemic lupus erythematosus (SLE) (n = 144) had significantly higher iC3b/C3dg levels as compared to healthy individuals (n = 144) (p < 0.0001). We present two functional immunoassays, that are able to measure systemic levels of the C3-activation products iC3b and C3dg in mice and humans. To our knowledge, these are the first assays for complement activation that use a physiological relevant capture construct such as CR2. These assays will be a relevant tool when investigating mouse models and human diseases involving the complement system.

Background: Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) disease is a well-known antibody-induced autoimmune disease. The pathogenesis of AAV has not yet been completely clarified, but may be related to heredity, infection, environmental factors, cellular immunity, etc. In recent years, complement in AAV pathogenesis has become the latest research hotspot, and the decrease of serum complement C3 is associated with poor prognosis of anti-neutrophil cytoplasmic antibody-associated glomerulonephritis. In the current study, we investigated the associations between serum complement C3 and kidney injury in AAV children. Methods: Twenty-four children with AAV admitted to our hospital from June 2014 to June 2019 were divided into the low C3 group and the normal C3 group. All the children have undergone renal biopsy. The clinical manifestations, laboratory tests, renal pathology, treatment, and prognosis of the 2 groups were observed. The primary end point was end-stage renal disease (ESRD). Results: It was shown that kidney injury was more obvious in patients with low C3 than in patients with normal C3 serum. The values of ESR, Scr, and UA before treatment in the low C3 group were higher than those in the normal C3 group (p < 0.01); the values of RBC, Hb, PLT, ALB, LDH, and eGFR in the normal C3 group were higher than those in the low C3 group (p < 0.01). The values of urinary protein and NAG enzyme in the low C3 group were higher than those in the normal C3 group (p < 0.01). The area of glomerular abandonment, sclerosis, segmental sclerosis, crescent, cellular crescent, cellular fibrous crescent, fibrous crescent, segmental loop necrosis, and the number of cases with acute renal tubulointerstitial lesions in the low C3 group were bigger than those in the normal C3 group (p < 0.05 and < 0.01). The number of cases with C3 deposition in the low C3 group was higher than that in the normal C3 group (p < 0.05). The number of patients receiving CRRT and PE in the low C3 group was higher than that in the normal C3 group (p < 0.05 and < 0.01). In this study, 3 children entered the stage of ESRD and 1 died in the low C3 group. Conclusion: The kidney injury of AAV children with low complement C3 is serious, and the prognosis is poor. We should pay attention to the influence of decreased complement C3 on the condition and prognosis of AAV children.

Introduction We tested the hypothesis that low plasma complement C3 is observationally and genetically associated with high risk of Alzheimer's disease (AD). Methods We studied 95,442 individuals enrolled in the Copenhagen General Population Study. In genetic analyses, we further included 8367 individuals from the Copenhagen City Heart Study. In the two studies, 1189 and 35 developed AD during median 8 years follow-up. Results The multifactorially adjusted hazard ratio for risk of AD for a one standard deviation lower levels of complement C3 was 1.11 (95% confidence interval: 1.04–1.19) in all individuals and 1.66 (1.33–2.07) in APOE e44 carriers. In Mendelian randomization, the corresponding genetic estimates were 1.66 (1.05–2.63) overall and 1.99 (0.52–7.65) in APOE e44 carriers. Discussion Low baseline levels of complement C3 were associated with high risk of AD. The risk was amplified in APOE e44 highly susceptible individuals, and these findings were substantiated by a Mendelian randomization approach, potentially implying causality. Based on these findings, we present and thoroughly discuss an updated Alzheimer hypothesis incorporating low complement C3 levels.

Objective.Infections remain a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). The high prevalence of infections in SLE is attributed to both the disease and its treatments. The complement system plays an important role in host immune responses against invading microorganisms. We sought to provide the experimental and clinical evidence supporting the hypothesis that low levels of complement factors cause defective complement-mediated opsonization in patients with SLE.Methods.Staphylococcus aureuswas opsonized with sera from healthy individuals (n = 16), SLE patients with normal (n = 5) or low complement (n = 8) levels. Phagocytosis ofS. aureusby healthy human neutrophils was analyzed by an imaging flow cytometry-based method. We retrospectively examined the infection incidence in relation to complement levels in a cohort of 165 patients with SLE during a 1.5-year period. The association was analyzed for infection incidence and disease-related variables.Results.Uptake ofS. aureusby neutrophils was decreased whenS. aureuswas opsonized with sera from SLE patients with low complement levels compared to sera from healthy individuals and SLE patients with normal complement. In our SLE cohort, 44% of patients had at least 1 infection during the 1.5 years. No significant association was observed between complement levels and infection risk. Importantly, high-dose glucocorticoids (GC; prednisone ≥ 10 mg/day) were the most important predictive factor for infections in patients with SLE.Conclusion.Low complement levels affect bacterial opsonization in SLE blood and lead to downregulated phagocytosis by neutrophils. High-dose GC increase the infection risk in patients with SLE.

Symptomatic cytomegalovirus (CMV) infections are rare in patients with no previous history of immunosuppressive therapy or condition. A 33-year-old woman with type-2 diabetes, endstage renal disease (ESRD) and unexplained lower extremity weakness was admitted with failure to thrive, ongoing hemolysis, low haptoglobin and C3 levels and suppressed IgM and IgG globulin fractions. Multiple cultures and serologic workup for autoimmune disorders remained negative. CMV viral titer by serum polymerase chain reaction (PCR) revealed massive elevation at 9.2 million copies/mL. Initial CMV IgG titer was positive, IgM titer remained consistently negative and CMV was recovered from cerebrospinal fluid, as well. She received treatment with I.V. ganciclovir, CMV immune globulin (CytoGam) and three sessions of plasmapheresis (PLEX). The extreme viremia without neutropenia, lack of IgM antibody reconversion and CMV-mediated hemolysis with a low complement level were all very unusual features. Timely initiation of PLEX may have contributed to recovery

Background Acquired complement deficiency can occur in the setting of autoimmune syndromes, such as systemic lupus erythematosus (SLE), with very low or, occasionally, undetectable C3 levels. Based on inherited complement defects, patients with transiently low complement may be at similar risk for serious bacterial infection, but the degree of risk related to C3 level and temporal association is unknown. Methods We performed a retrospective study including pediatric patients with undetectable total complement activity or absent individual complement components measured at our institution from 2002 to 2018. We assessed annual rate of serious bacterial infection (SBI) defined as requiring hospitalization and/or parenteral antibiotics by manual chart review. Among included SLE patients, we assessed the 30-day probability of SBI for given C3 measurements using a logistic regression model to determine risk. Primary complement deficiency was analyzed for SBI rate as comparison. Covariates included age, level of immune suppression and history of lupus nephritis. Results Acquired complement deficiency secondary to SLE-related disease [n = 44] was the most common underlying diagnosis associated with depressed complement levels and were compared to a cohort of primary complement deficient patients [n = 18]. SBI per 100 person-years and cohort demographics were described in parallel. Our logistic regression analysis of pediatric patients with SLE showed low C3 level was temporally associated with having an SBI event. Given equivalent immunosuppression, patients with an SBI had lower C3 levels at the beginning of the observation period relative to patients without SBI. Conclusion Pediatric patients with the diagnosis of SLE can develop very low C3 levels that associate with risk of serious bacterial infection comparable to that of patients with primary complement deficiency. Patients prone to severe complement consumption may particularly be at risk.

A 23-year-old woman with fever, oral ulcers, arthalgias and weight loss of 2-week duration suddenly developed blurred vision, with reduced visual acuity, cotton wool exudates and retinal vascular tortuosity. Laboratory testing revealed anaemia, lymphopaenia, positive antinuclear antibody and high anti-dsDNA antibody titre with low complement components. There was no evidence of infection, clinching the diagnosis of lupus retinopathy. Steroid therapy alone was highly effective and was also accompanied by a normalisation of haemoglobin and lymphocyte counts, after which azathioprine was added. Hydroxychloroquine was introduced after resolution of retinal changes. Immunosuppressive therapy was progressively tapered over the course of 12 months and then discontinued, and the patient remains in remission 48 months after the initial presentation. Our patient exemplifies a very rare manifestation of systemic lupus erythematosus. We emphasise the importance of its early detection and complexity of treatment in order to reduce visual morbidity.

Author(s): Ramsey-Goldman, Rosalind; Alexander, Roberta Vezza; Massarotti, Elena M; Wallace, Daniel J; Narain, Sonali; Arriens, Cristina; Collins, Christopher E; Saxena, Amit; Putterman, Chaim; Kalunian, Kenneth C; O'Malley, Tyler; Dervieux, Thierry; Weinstein, Arthur | Abstract: ObjectiveTo evaluate the frequency of cell-bound complement activation products (CB-CAPs) as a marker of complement activation in patients with suspected systemic lupus erythematosus (SLE) and the usefulness of this biomarker as a predictor of the evolution of probable SLE into SLE as classified by the American College of Rheumatology (ACR) criteria.MethodsPatients in whom SLE was suspected by lupus experts and who fulfilled 3 ACR classification criteria for SLE (probable SLE) were enrolled, along with patients with established SLE as classified by both the ACR and the Systemic Lupus International Collaborating Clinics (SLICC) criteria, patients with primary Sjogren's syndrome (SS), and patients with other rheumatic diseases. Individual CB-CAPs were measured by flow cytometry, and positivity rates were compared to those of commonly assessed biomarkers, including serum complement proteins (C3 and C4) and autoantibodies. The frequency of a positive multianalyte assay panel (MAP), which includes CB-CAPs, was also evaluated. Probable SLE cases were followed up prospectively.ResultsThe 92 patients with probable SLE were diagnosed more recently than the 53 patients with established SLE, and their use of antirheumatic medications was lower. At the enrollment visit, more patients with probable SLE were positive for CB-CAPs (28%) or MAP (40%) than had low complement levels (9%) (P = 0.0001 for each). In probable SLE, MAP scores of g0.8 at enrollment predicted fulfillment of a fourth ACR criterion within 18 months (hazard ratio 3.11, P l 0.01).ConclusionComplement activation occurs in some patients with probable SLE and can be detected with higher frequency by evaluating CB-CAPs and MAP than by assessing traditional serum complement protein levels. A MAP score above 0.8 predicts transition to classifiable SLE according to ACR criteria.

Nephrotic syndrome affects both children and adults. Idiopathic nephrotic syndrome is reported to be one of the most frequent renal pathologies in childhood. Nephrotic children are at high risk for severe pneumococcal infections as one of the life-threatening complications of nephrotic syndrome due to involvement of the immunosuppressive regimen and the acquired immune deficiency induced by nephrotic syndrome including decreased plasma IgG and low complement system components. Aiming to prevent pneumococcal infection is of paramount importance especially in this era of ever-increasing pneumococcal resistance to penicillins and cephalosporins. The pneumococcal vaccines currently available are inactivated vaccines—the two main forms in use are polysaccharide vaccines and conjugated vaccines. However, the data supporting the use of these vaccines and to guide the timing and dosage recommendations is still limited for nephrotic children. Thus, this review discusses the evidences of immunogenicity and safety profile of both vaccinations on nephrotic patients as well as the effect of nephrotic syndrome treatment on vaccine seroresponses.

Background Regional differences have been identified as potential confounders of SLE clinical trial results. Recently, no difference between treatment and placebo was observed in the US lupus patients when a significant treatment effect was observed in Europe1. Objectives To compare SLE serologic features/markers of active disease between different geographic regions in recent multinational clinical trials. Methods Laboratory data of 1005 subjects from four global randomized SLE clinical trials at baseline were examined. Mean/median C3 and C4 complement levels, prevalence of low C3 or C4 (Low C3/C4), positive anti-double stranded DNA (DNA), anti-Extractable Nuclear Antibodies (ENA), and high-titer Antinuclear Antibody (ANA≥1:640) in North America (NA) patients were compared to Asia (AS), Latin America (LA), Africa (AF), Western Europe (WE), and Eastern Europe (EE) Results NA patients were significantly older than patients in LA, AF, or AS but not WE or EE. Not surprisingly, they also had higher complement levels and the lowest rates of low C3/C4, DNA, ENA, and ANA ≥1:640. Our data confirm that age is an important factor in the prevalence of low complement and autoantibodies. However, there remained a marked difference in serologic activity between NA and EE, despite being close in age. Asian patients were the youngest, had the lowest complement levels and the highest rate of ENA & DNA consistent with high disease activity. Low complement, but not DNA, was relatively common in Europe. LA patients, like Asians, had high rates of serologic activity but less incidence of low C3/C4, suggesting that this population may have intrinsic disease severity without being as acutely active. Conclusion SLE patients entering studies from North America are strikingly less likely to have markers of active disease than other regions, raising concerns for their suitability for trials. This appears to be associated, at least in part, with age, although more aggressive treatments cannot be ruled out. Asian subjects have the greatest prevalence of autoantibodies and low complement. Latin American patients have high prevalence of ANA≥1:640 and other autoantibodies, but less evidence of low complements. These findings may help to explain regional differences in treatment/placebo responses and emphasize the importance of geographical stratification and improved methods to screen out patients unsuitable for SLE trials. Reference [1] www.immupharma.co.uk Disclosure of Interests Ewa Olech Grant/research support from: Bristol Myers Squibb, Eduard van Rijen: None declared, Ali Ashrafzadeh Employee of: Employee of IQVIA, Alexander Kant: None declared, Joan T Merrill Grant/research support from: Genentech, UCB, GSK, EMD Serono, Pfizer, Celgene, Exagen, Bristol Myers Squibb, Medimmune/Astra Zeneca, Lilly, Amgen, Xencor, Neovacs, Consultant for: Genentech, UCB, GSK, EMD Serono, Pfizer, RemeGen, Celgene, Exagen, Bristol Myers Squibb, Medimmune/Astra Zeneca, Lilly, Immupharma, Amgen, Janssen, Sanofi, Neovacs, Anthera, Speakers bureau: UCB, GSK, EMD Serono, Bristol Myers Squibb, Medimmune/Astra Zeneca, Janssen

Background To describe patients with inherited and acquired complement deficiency who developed invasive meningococcal disease (IMD) in England over the last decade. Methods Public Health England conducts enhanced surveillance of IMD in England. We retrospectively identified patients with complement deficiency who developed IMD in England during 2008–2017 and retrieved information on their clinical presentation, vaccination status, medication history, recurrence of infection and outcomes, as well as characteristics of the infecting meningococcal strain. Results A total of 16 patients with 20 IMD episodes were identified, including four with two episodes. Six patients had inherited complement deficiencies, two had immune-mediated conditions associated with complement deficiency (glomerulonephritis and vasculitis), and eight others were on Eculizumab therapy, five for paroxysmal nocturnal haemoglobinuria and three for atypical haemolytic uraemic syndrome. Cultures were available for 7 of 11 episodes among those with inherited complement deficiencies/immune-mediated conditions and the predominant capsular group was Y (7/11), followed by B (3/11) and non-groupable (1/11) strains. Among patients receiving Eculizumab therapy, 3 of the 9 episodes were due to group B (3/9), three others were NG but genotypically group B, and one case each of groups E, W and Y. Conclusions In England, complement deficiency is rare among IMD cases and includes inherited disorders of the late complement pathway, immune-mediated disorders associated with low complement levels and patients on Eculizumab therapy. IMD due to capsular group Y predominates in patient with inherited complement deficiency, whilst those on Eculizumab therapy develop IMD due to more diverse capsular groups including non-encapsulated strains.

Background Cell Bound Complement Activation Products (CB-CAPs), are stable form of classical complement activation, ex-vivo, and sensitive and specific marker of SLE. In the present study, we sought to compare the performances of CB-CAPs to gold standard low complement C3 or C4. Methods All subjects (n=1200) were adults (18 years) and enrolled from multiple academic Centers in the United States. All SLE fulfilled the 1997 ACR criteria for SLE (n=498). Patients with Other Rheumatic Diseases (n=450) consisted of 189 rheumatoid arthritis, 88 Sjogrens, 90 Fibromyalgia and 83 patients with other connective tissues diseases. A group of healthy normal individuals was also enrolled (n=252). Abnormal CB-CAPs status (EC4d or BC4d>99 th percentile of normal) were determined using flow-cytometry. Complement C3 and C4 levels were determined using immunoturbidimetry (Binding Site, San Diego, CA) assay kits. Performances of the markers, either alone or in combination to distinguish SLE from other rheumatic diseases and controls were established using Sensitivity, Specificity, Odds Ratio and Area under the Curve (AUC) of the Receiver Operating Characteristic curve (ROC). Youden Index (Sensitivity +Specificity - 100) was also calculated. The combination of 4 complement marker abnormalities were also evaluated using logistic regression and unweighted composite score cumulating the presence of these abnormalities was calculated. Results Abnormal CB-CAPs status yielded 62% sensitivity with 88% specificity in distinguishing SLE from the group of patients with other diseases (table 1). Youden Index was 0.492±0.027. Low C3/C4 status yielded 38% sensitivity and 93% specificity in distinguishing SLE from the group of patients with other diseases. Youden Index was 0.313±0.025 for Low C3 or C4 and significantly lower than Youden score associated with abnormal CB-CAPs (p Conclusions Our data suggests that CB-CAPs have greater diagnostic yield than low complement C3/C4. The combination of these complement abnormalities in composite complement score has high yield in distinguishing SLE from other rheumatic diseases and normal healthy individuals. Funding Source(s): Exagen.

Background:A subgroup of lupus patients present with mild symptoms and immunologic features, while they do not meet classification criteria for SLE. This disease state can be referred to as “incomplete systemic lupus erythematosus” (iSLE). Up to 55% of iSLE patients progress to SLE. Furthermore, previous research has shown that iSLE might overlap with early primary Sjögren’s disease (pSS).(1) Unfortunately, there are no predictive markers available for progression to classifiable disease. Type-I interferon (IFN) plays an important role in disease initiation of both SLE and pSS.(2,3) Myxovirus-resistance protein A (MxA) is a GTP-ase that has previously be demonstrated to correlate strongly with IFN-type I expression. Furthermore, interferon-inducible chemokines IFN-γ induced protein 10 (IP-10), and B-cell activating factor (BAFF), that are both inducible by IFN, are of interest, because it is demonstrated that these proteins are increased prior to the diagnosis of SLE.(4)Objectives:To find predictive markers that identify patients with incomplete systemic lupus erythematosus (iSLE) who are at the highest risk to progress to classifiable systemic lupus erythematosus (SLE) or primary Sjögren’s syndrome (pSS).Methods:Patients with iSLE (ANA ≥ 1:80, ≥ 1 clinical SLICC criterion, but not fulfilling the criteria, and disease manifestation Results:Of 38 included iSLE patients, 6 had developed SLE and 1 develop pSS (18%) after median follow up of 36 months. The 7 patients who developed SLE/pSS were all women, and were younger at baseline than those who remained having iSLE (median 26 years, IQR 20-29 vs. median 42 years, IQR 30-56, p=0.0009). Over time, these patients had significantly lower complement 3 (pFigure 1.Conclusion:Gender, age at diagnosis, persistent low complement levels, and high IFN-gene expression can help to identify iSLE patients at the highest risk of progressing to classifiable disease.References:[1]Md Yusof MY, et al. Prediction of autoimmune connective tissue disease in an at-risk cohort: Prognostic value of a novel two-score system for interferon status. Ann Rheum Dis. 2018;1–8.[2]Yao Y, et al. Type I interferons in Sjögren’s syndrome. Autoimmun Rev. 2013;12(5):558–66.[3]Crow MK. Type I Interferon in the Pathogenesis of Lupus. J Immunol [Internet]. 2014;192(12):5459–68.[4]Lu R, et al. Dysregulation of innate and adaptive serum mediators precedes systemic lupus erythematosus classification and improves prognostic accuracy of autoantibodies. J Autoimmun. 2016;74:182–93.Disclosure of Interests:None declared

Post-infectious glomerulonephritis has become exceptional in France because streptococcus infections are well-treated. When they appear, clinical and biological symptoms are mostly typical and associate acute nephritic syndrome, acute renal failure, proteinuria, hematuria and low complement. We are reporting the first French case of acute post-infectious glomerulonephritis related to Streptococcus equi subsp. zooepidemicus, which is commonly found in horses and rarely in human pathology, and of which contamination is by direct contact with sick horses or by ingestion of non-pasteurized milk.

Objective: Most of the patients with proliferative lupus nephritis (LN) have high titer of anti-dsDNA antibody and low complement levels. In this study, we tried to predict proliferative LN with serological profile. Methods: This prospective study was conducted in fifty pateints with known systemic lupus erythematosus (SLE) with laboratory evidence of LN (proteinuria, microscopic hematuria, or increased serum creatinine). Serological profile (anti-dsDNA, C3, and C4) and renal biopsy were done in all patients. Results: Of 50 patients, 35 had Class IV (70%), 7 Class II (14%), 4 Class V (8%), and 4 had Class IV and V (8%) on renal biopsy. Totally, 39 (78%) patients had proliferative LN (Class IV and Class IV and V). The prevalence of anti-dsDNA, low C3, and low C4 was 97.1%, 68%, and 74% with LN and 97.4%, 84.6%, and 87.2% with proliferative LN (P < 0.001), respectively. About 72% (28 of 39 patients) with proliferative LN had the combination of anti-dsDNA positivity, low C3, and low C4 levels. However, whoever had the combination of anti-dsDNA positivity, low C3, and low C4 showed only proliferative LN on biopsy. Positive predictive value was 100% (P < 0.05). None of the patients with Class II or Class V (nonproliferative LN) had this combination of serology. Conclusion: In this study, it was found that proliferative LN can be predicted by serological profile alone. Thus it might be argued that immunosuppressive therapy (steroids and mycophenolate mofetil) may be started without renal biopsy in a known SLE patient with laboratory evidence of LN and positive serology; however, robust studies are required.

Complement activation and low complement levels are common in systemic lupus erythematosus (SLE). Antiphospholipid antibodies (aPL) are found in about 30-40% of patients with SLE. This study aimed to investigate the association between aPL and complement levels in patients with SLE. Serum samples were collected from 269 patients with SLE enrolled in the Norwegian Systemic Connective Tissue and Vasculitis Registry (NOSVAR) during 2003-2009, and from 353 controls. All samples were analysed for anti-β2 glycoprotein 1 (anti-β2GP1) and anticardiolipin antibodies (aCL), C-reactive protein (CRP) and complement components C3 and C4. Median CRP level was significantly higher in cases than in controls (2.06 versus 0.90 mg/l; P

Complement activation plays an important role in pharmacokinetic and performance of intravenously administered nanomedicines. Significant efforts have been directed toward engineering of nanosurfaces with low complement activation, but due to promiscuity of complement factors and redundancy of pathways, it is still a major challenge. Cell membrane-anchored Decay Accelerating Factor (DAF, a.k.a. CD55) is an efficient membrane bound complement regulator that inhibits both classical and alternative C3 convertases by accelerating their spontaneous decay. Here we tested the effect of various short consensus repeats (SCRs, “sushi” domains) of human CD55 on nanoparticle-mediated complement activation in human sera and plasma. Structural modeling suggested that SCR-2, SCR-3 and SCR-4 are critical for binding to the alternative pathway C3bBb convertase, whereas SCR-1 is dispensable. Various domains were expressed in E.coli and purified by an affinity column. SCRs were added to lepirudin plasma or sera from different healthy subjects, to monitor nanoparticle-mediated complement activation as well as C3 opsonization. Using superparamagnetic iron oxide nanoworms (SPIO NWs), we found that SCR-2-3-4 was the most effective inhibitor (IC50 ~0.24 μM for C3 opsonization in sera), followed by SCR-1-2-3-4 (IC50 ~0.6 μM), whereas shorter domains (SCR-3, SCR-2-3, SCR-3-4) were ineffective. SCR-2-3-4 also inhibited C5a generation (IC50 ~0.16 μM in sera). In addition to SPIO NWs, SCR-2-3-4 effectively inhibited C3 opsonisation and C5a production by clinically approved nanoparticles (Feraheme, LipoDox and Onivyde). SCR-2-3-4 inhibited both lectin and alternative pathway activation by nanoparticles. When added to lepirudin-anticoagulated blood from healthy donors, it significantly reduced the uptake of SPIO NWs by neutrophils and monocytes. These results suggest that soluble domains of membrane-bound complement inhibitors are potential candidates for preventing nanomedicine-mediated complement activation in human subjects.

The complement system has an important role in the pathogenesis of vasculitis associated with antineutrophilic cytoplasmic antibody (AAV) mainly at the level of the kidneys because patients with complement deposits on the glomerular basal membrane present more aggressive disease compared with those with pauci-immune vasculitis.To analyze the association of hypocomplementemia with the clinical manifestations, laboratory data, renal histology, progress to renal insufficiency, and mortality of patients with AAV.Retrospective cohort study (2000-2007) included 93 patients with AAV. Hypocomplementemia is defined as having C3 values lower than 80 mg/dL or C4 values below 15 mg/dL. Demographic, statistical, clinical, hematological, serological, and histopathological characteristics of all the patients with and without diagnosis of hypocomplementemia were compared. In order to evaluate variable independence, a logistic regression analysis was used.Ninety-three patients were studied of whom 63 (67.7%) had complement dosage at the moment of AAV diagnosis. Seven patients (11.1%) presented hypocomplementemia and a greater kidney involvement compared with normocomplementemic patients. Thirty renal biopsies were analyzed and 4 (13.3%) showed immunocomplex (IC) or complement deposits by an immunofluorescence test (IFT). Patients with "non-pauci-immune" AAV also presented terminal chronic renal disease (TCRD).There is an association between low complement and the degree of renal damage in patients with AAV. Patients with renal biopsies confirming IC and/or complement deposits showed more aggressive renal disease. Key Points • The complement system has an important role in the pathogenesis of vasculitis associated to antineutrophilic cytoplasmic antibody. • The studies in murine models confirming the complement activation by alternative pathway and particularly the receptor C5a (C5aR) is necessary for the development of glomerulonefritis. • Complement deposit observed in the renal biopsies of patients diagnosed with AAV was correlated to greater kidney damage, greater proteinuria and major disease activity compared to patients diagnosed with typical pauci-immune vasculitis. • The presence of hypocomplementemia at the onset of the disease was also associated with a greater organ involvement, poor prognosis and greater mortality.

Prognosis of pregnancies in women with antiphospholipid syndrome has dramatically improved over the past two decades using conventional treatment with low molecular weight heparin and low-dose aspirin. However, despite this regimen, 10–15% of antiphospholipid syndrome patients experience pregnancy losses. Several studies have been performed in order to identify risk factors predictive of complications. Thrombosis has been generally accepted as the key pathogenetic mechanism underlying pregnancy morbidity. However, the thrombogenic state alone is not able to explain all the different mechanisms leading to pregnancy failure. In fact, emerging evidence shows that complement pathway could play an important role in mediating clinical events in antiphospholipid syndrome. However, the exact mechanism through which complement mediates antiphospholipid syndrome complications remains unknown. Low complement levels (C3 and C4) are associated with poor pregnancy outcome in women with antiphospholipid syndrome in different studies. Hypocomplementemia could be indicated as an early predictor of adverse pregnancy outcome, available at the beginning of pregnancy for starting, if necessary, additional treatment to conventional therapy. However, future studies need to better understand the impact of low complement level on antiphospholipid syndrome pregnancy outcome.

ObjectivesTo evaluate the association between lupus severity and cell-bound complement activation products (CB-CAPs) or low complement proteins C3 and C4.MethodsAll subjects (n=495) fulfilled the American College of Rheumatology (ACR) classification criteria for SLE. Abnormal CB-CAPs (erythrocyte-bound C4d or B-lymphocyte-bound C4d levels >99th percentile of healthy) and complement proteins C3 and C4 were determined using flow cytometry and turbidimetry, respectively. Lupus severity was estimated using the Lupus Severity Index (LSI). Statistical analysis consisted of multivariable linear regression and groups comparisons.ResultsAbnormal CB-CAPs were more prevalent than low complement values irrespective of LSI levels (62% vs 38%, respectively, p2=0.145).ConclusionAbnormalities in complement activation as measured by CB-CAPs are associated with increased LSI.

OBJECTIVE The impact of pulmonary infection (PI) on mortality of patients with systemic lupus erythematosus (SLE) has been established. Nevertheless, the effect of risk factors in mortality remains controversial. The objective of this study is to determine the risk factors of short-term mortality among SLE patients with PI. METHOD The clinical data of 54 SLE patients with 59 episodes of PI who were hospitalized from January 2013 to May 2018 was retrospectively analyzed. Demographic data, clinical features, and outcomes were collected. Logistic regression analysis was carried out to determine the independent predictors of 60-day mortality during hospitalization. We used receiver operating characteristics (ROC) curves to verify the indices as mortality predictors in the study patients. RESULTS There were a total of 54 patients with 59 episodes of PI. There were 12 deaths during hospitalization. In multivariate analysis, 24-hour urinary protein (24h-PRO) (odds ratio [OR]: 2.713, 95% CI: 1.234-5.965, P = 0.013), peripheral lymphocyte count (OR: 0.066, 95% CI: 0.005-0.887, P = 0.040), and serum complement 3 level (C3) (OR: 0.097, 95% CI: 0.010-0.954, P = 0.045) were associated with mortality among our cohort of SLE patients with PI. ROC curve values were 0.818 for lymphocyte count (95% CI: 0.696-0.907, P = 0.001), 0.894 for 24h-PRO (95% CI: 0.786-0.959, P

Background Lupus nephritis (LN) affects ∼70% of systemic lupus erythematosus (SLE) patients and is one of the main contributors to morbidity and mortality. While defective clearance of apoptotic cells (AC), immune complexes, and type 1 interferons (IFN) are strongly implicated in lupus pathogenesis, the precise way that each impacts kidney protection and injury is unknown. Methods To investigate mechanisms of kidney injury in a lupus-like disease model, we created C57BL/6 mice with defective clearance of AC (Mfge8-/-) and anti-chromatin antibodies (sle1) that were also deficient in either C1q [C1q Triple mutant (C1qTM)] or C3 (C3TM). Kidney injury was evaluated by urine albumin/creatinine ratio (UCAR), PAS staining, and immunofluorescence (IF) staining. The effect of IFN-I on disease was studied in C3TM mice by a single injection of an adenovirus expressing IFNα (AdV-IFNα). Results Sle1 mice deficient in MFGE8 developed significantly higher titers of autoantibodies directed at lupus antigens compared to sle1 mice alone. When MFGE8-/- Sle1 mice also had C1q or C3 deficiency, a further increase in anti-DNA (figure 1A) and other autoantibodies was observed. Both TM strains showed AC accumulation in the kidneys (figure 1B) and C1qTM mice had decreased survival. Remarkably, we detected glomerular deposition of C3/C3d in C1qTM (figure 1C) and the membrane attack complex (MAC) in C3TM mice. To dissociate the effects of complement on B cells versus effects on the kidney, we studied antibody mediated kidney injury (Nephrotoxic Nephritis, NTN) in mice deficient in AC clearance and complement proteins [double knockout (DKO) (Mfge8-/-C1q-/- or Mfge8-/-C3-/-) mice]. NTN in C1q DKO and C3 DKO mice revealed a significantly elevated UACR compared to the single mutants. IF analyses also revealed glomerular C3/C3d deposition in C1qDKO mice and MAC deposition in C3DKO mice. A single injection of AdV-IFNα accelerated kidney damage in C3TM mice, resulting in increased anti-dsDNA IgG titers, UACR, and PAS staining. Conclusions These findings demonstrate that early component complement deficiencies have two distinct effects: they promote enhanced B cell autoreactivity and they protect against kidney disease. Increased glomerular C3/C3d deposition in C1qTM and NTN C1qDKO mice suggest activation of the lectin or alternative complement pathways. Increased MAC deposition in C3TM and NTN C3DKO mice indicates that a C3–independent mechanism leads to distal complement activation and MAC formation. These data prompt models of tissue injury in low complement states that will require assessment in human SLE and provide rationale for targeted therapeutics that are not currently used.

Background In the view of applying a treat to target (T2T) strategy in the management of systemic lupus erythematosus (SLE), a novel definition of minimal acceptable disease activity – the lupus low disease activity state (LLDAS) [1] – and clinical remission (CR) [2] were recently proposed. Objectives To compare attainability and outcomes of LLDAS and CR as treatment targets in the early stages of SLE management. Methods LLDAS and CR prevalence were analysed at 6 (T1) and 18 (T2) months after treatment initiation (T0) in a monocentric cohort of 107 (median disease duration 9.7 months) prospectively followed Caucasian SLE patients. LLDAS was defined as SLE disease activity index 2000 (SLEDAI-2K)≤4 without major organ activity and no new disease activity, physician global assessment (0–3)≤1, prednisone ≤7.5 mg/day and well-tolerated immunosuppressant dosages. CR was defined as clinical SLEDAI-2K=0 (increased anti-dsDNA and low complement were excluded) and prednisone ≤5 mg/day in patients treated with/without stable immunosuppressants and/or antimalarials. Multivariate models were built to identify factors associated with failure to achieve LLDAS and CR, as well as to investigate relationship between the latter and early damage accrual (defined as SLICC/Damage Index≥1 at T2). Results LLDAS was achieved significantly more frequently than CR both at T1 [47 (43.9%) vs. 25 (23.4%); p Conclusions During the early stages of SLE, LLDAS and CR overlap definitely less frequently than reported in long-standing disease (53.2%–66.7% vs 83.9%–96.5% [2]). Although remission is recommended as the primary treatment target in SLE, LLDAS may represent a valid alternative in the first stages of disease management, being more attainable compared to CR and negatively associated to early damage. References [1] Franklyn K, et al. Ann Rheum Dis2016;75:1615–21. [2] Zen M, et al. Ann Rheum Dis2017;76:562–5. Disclosure of Interest None declared

Background Hypocomplementemia (HC) represents a significant clinical finding in Systemic Lupus Erythematosus (SLE) as it suggests complement activation by immune-complexes, which can initiate inflammation. As disease activity contributes to damage accrual in SLE patients, we investigated the role of HC as a predictor of subsequent organ damage. Objectives Investigate the relationship between HC, disease flares and organ damage accrual in SLE patients. Methods Longitudinal cohort study of 102 SLE patients with HC defined as a C3 and/or C4 levels below cut-off during median follow-up of 13.8 years (IQR 7.0, 23.1). Disease activity was scored by time averaged SLEDAI-2K without the serological components (cWAS), flares by SELENA-SLEDAI and damage accrual by SLICC-DI. Analysis included comparisons between normocomplementemic (NC) and hypocomplementemic (HC) patients, and multivariate logistic and Cox regression modelling determined the predictive value of HC on organ damage. Results HC occurred in 2/3 of patients overall and was more often due to low C3 (97%) than low C4 (54%). HC patients had a higher prevalence of anti-dsDNA Ab (72% vs 36%, p 0, n=60) associated with HC was similar as for NC patients (OR 1.08, p>0.20). Conclusions Low complement levels occur in 2/3 of SLE patients but have negligible impact on time averaged disease activity and damage accrual in SLE. Discrepancies between low C3, low C4 and anti-dsDNA Ab occurrence indicate that in SLE alternative complement activation occurs frequently and requires further translational study. Acknowledgements The Rheumatology Group of UWA (JN) was supported by an unrestricted grant from the Arthritis and Osteoporosis Foundation of Western Australia (AOWA). The AOWA provided WR with a PhD Scholarship in Memory of Johan Donald Stewart. Disclosure of Interest None declared

Therapy for systemic lupus erythematosus (SLE) remains challenging. The long-term use of glucocorticoids (GC) and cytostatics considerably improves life expectancy, but at the same time favors the development of irreversible organ damages. To evaluate the efficacy of belimumab (BLM), a biological agent, that blocks B-lymphocyte-stimulating factor registered for the treatment of active SLE, is an important task of the practice of rheumatology. Objective: to evaluate the efficacy and safety of BLM in patients with high and moderate SLE activity. Subjects and methods. The investigation enrolled 16 patients with a Systemic Lupus Erythematosus Disease Activity Index (SLEDAI-2K) score of 6 to 19, who were positive for antinuclear factor (100%) and had low complement levels and high anti-native DNA antibodies (81%). BLM was used as monthly intravenous infusions at a dose of 10 mg/kg. The efficiency and safety of the therapy were evaluated monthly and 1 year after the initiation of treatment with BLM; SLE activity was estimated using SLEDAI-2K; a physician’s global assessment of disease activity on a visual analogue scale (VAS); anti-DNA antibody level changes, complement levels, a GC dose, damage index, and adverse events were determined. Results and discussion. BLM therapy proved to be effective in 62% of cases at 1 year after therapy initiation. At 1 month, SLE activity significantly decreased with SLEDAI-2K score diminishment from 9.31±3.21 to 6.25±2.80 in the entire group (p < 0.04). Over a month, the physician’s global assessment of disease activity significantly reduced from 19.25±6.60 to 13.68±3.97 mm (р

Summary The objective of this study was to explore the involvement of collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1) and other pattern recognition molecules (PRMs) of the lectin pathway of the complement system in a cross-sectional cohort of systemic lupus erythematosus (SLE) patients. Concentrations in plasma of CL-L1, CL-K1, mannan-binding lectin (MBL), M-ficolin, H-ficolin and L-ficolin were determined in 58 patients with SLE and 65 healthy controls using time-resolved immunoflourometric assays. The SLE patients' demographic, diagnostic, clinical and biochemical data and collection of plasma samples were performed prospectively during 4 months. CL-L1, CL-K1 and M-ficolin plasma concentrations were lower in SLE patients than healthy controls (P-values < 0·001, 0·033 and < 0·001, respectively). H-ficolin concentration was higher in SLE patients (P < 0·0001). CL-L1 and CL-K1 plasma concentrations in the individuals correlated in both patients and controls. Patients with low complement component 3 (C3) demonstrated a negative correlation between C3 and CL-L1 and CL-K1 (P = 0·022 and 0.031, respectively). Patients positive for anti-dsDNA antibodies had lower levels of MBL in plasma than patients negative for anti-dsDNA antibodies (P = 0·02). In a cross-sectional cohort of SLE patients, we found differences in the plasma concentrations of CL-L1, CL-K1, M-ficolin and H-ficolin compared to a group of healthy controls. Alterations in plasma concentrations of the PRMs of the lectin pathway in SLE patients and associations to key elements of the disease support the hypothesis that the lectin pathway plays a role in the pathogenesis of SLE.

Some systemic sclerosis (Ssc) patients express antiphospholipid antibodies and their percentage varies within studies in the literature. The particular role of these antibodies in clinical manifestations of Ssc is still unknown. The aim of the study was to examine an extended panel of antiphospholipid antibodies in Ssc patients who did not have any clinical features of antiphospholipid antibody syndrome. A cross-sectional study was designed and 36 consecutive patients with Ssc were recruited. A relatively high proportion of patients (14 patients - 38.9%) had antiphospholipid antibody presence. Most Ssc patients (11 patients - 30.6%) had IgM anti phosphatidyl ethanolamine antibodies. Serum IgM anti phosphatidyl ethanolamine antibodies, IgM anti prothrombin and IgG anti β2 glycoprotein 1 antibodies were associated with low complement levels in Ssc patients. In multivariate analysis, only serum IgM anti phosphatidyl ethanolamine antibodies concentration and serum IgG anti β2 glycoprotein 1 antibodies concentration were independently associated with hypocomplementemia after adjusting for age and gender. No other correlations with Ssc clinical characteristics were found. In conclusion, antiphospholipid antibodies are present in a large proportion of Ssc patients who do not have clinical features or a history of antiphospholipid antibodies. IgM anti phosphatidyl ethanolamine antibodies seem to be more frequent and the dominant antiphospholipid antibody type in the group recruited from the Romanian Ssc population.

Purpose Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder which mainly affects women in the reproductive age. Vitamin D appears to have an immunomodulatory action, low levels of vitamin D having been described in patients with autoimmune rheumatic diseases. The aim was to report vitamin D levels and their relationship with disease activity in a cohort of SLE patients. Methods A cohort of 20 patients, 18 female and 2 male is described. The patients were diagnosed with SLE and had arthralgias, cutaneous manifestations, fatigue and decreased complement levels. Blood levels of 25(OH)D3 were measured in all patients. 25(OH)D3 levels were measured by radioimmunoassay. The measurement of 25(OH)D3 by radioimmunoassay consisted of a two-step procedure. The first step involved a rapid extraction of 25(OH)D and other hydroxylated metabolites from serum or plasma with acetonitrile. Following extraction, the treated samples were then assayed by competitive RIA using an antibody with specificity to 25OHD. The sample, antibody and tracer were incubated for 90 min at 20–25 0C. Phase separation was accomplished after 20 min incubation at 20–25 0C with a second antibody precipitating complex. To reduce non-specific binding buffer was added after this incubation prior to centrifugation. The sensitivity of the assay was Results In the cohort of SLE patients low blood levels of 25(OH)D3 were observed. A positive relationship between 25(OH)D3 blood levels and complement levels was observed, namely low 25(OH)D3 levels were positively correlated with low complement levels. An inverse relationship was observed between 25(OH)D3 levels and disease activity, namely low 25(OH)D3 levels were related with high disease activity. Conclusions Vitamin D is a hormone directly related to the regulation of the musculoskeletal system. Vitamin D also has extraskeletal actions. The immunomodulatory action of vitamin D appears to be a key action of the hormone. In the work presented herein low blood levels of vitamin D were observed in SLE patients which were positively related to complement levels and inversely related to disease activity.

While it is a common practice to monitor complement levels in patients with systemic lupus erythematosus to aid in flare prediction and detection, it is unclear if this strategy is helpful in preventing subsequent organ damage. We studied longitudinal complement levels in 102 SLE patients during a median follow-up of 13.8 years (IQR 7.0, 23.1). Low complement was defined as C3 p<0.01) and aPL (74% vs 40%, p<0.01) but HC was concurrently present with anti-dsDNA Ab in only half the cases. The time-adjusted cWAS scores (1.9 vs 1.2, p=0.9), frequency (SDI > 0, n=60), and type of organ damage accrual were similar for patients with and without HC (OR 1.08, p>0.20). Intermittent or sustained HC has no predictive value for damage accrual in SLE or the underlying disease activity over time. This together with significant discrepancies in the concurrence of low C3, C4, and anti-dsDNA Ab indicates frequent activation of the complement pathway by other factors than immune complexes in SLE.

Objectives Low complement factor C4 is usually considered a valuable screening tool for patients with the potentially life-threatening hereditary angioedema with C1-inhibitor (C1-INH) deficiency (C1-INH-HAE). However, there are patients with C1-INH-HAE presenting with normal C4 levels. This means, that C1-INH-HAE may potentially be overlooked, if screening is performed only by measurement of C4. It has been suggested that measurement of C4 activation products is better suited to avoid false negative results. Our aim was to investigate whether total antigenic C4 or non-functional C4c is a better measure of the increased C4 activation in C1-INH-HAE patients. Design and methods Two different monoclonal antibodies (mAb) to human C4 were produced: one had specificity for the β-chain of C4 and would thus react with both functional and non-functional C4, and the other was developed against the factor I cleavage site on the α 3 -domain of C4 and was thus specific for activated, non-functional C4c. With these mAb we investigated plasma from 19 Danish C1-INH-HAE patients in three different enzyme-linked immunosorbent assays (ELISAs): a total antigenic C4 assay, a functional C4 assay and an assay measuring non-functional C4c. Results The amount of total antigenic C4 varied considerably between patients and 2 patients had total antigenic C4 levels in the normal area. Functional C4 was low in all C1-INH-HAE patients. A C4c/C4 ratio showed that around half the C4 measured in patients was non-functional and captured all C1-INH-HAE patients. Conclusions This study shows that the C4c/C4 ratio seems to be a better diagnostic measure than total antigenic C4 alone. Our findings underline that screening with total antigenic C4 implies a risk of overlooking C1-INH-HAE patients.

Background Recently, many connective tissue disease (CTD) patients wish to become a mother because immunosuppressants and biologics enable to improve the outcome of underlying CTD and quality of life respectively. However, Pregnancies in CTD patients often have problems including underlying disease exacerbation, some complications during pregnancy especially in preterm birth, light for date (LFD) and premature rapture of membrane (PROM). Previous study identified that high clinical activities with hypocomplementemia and positive anti-dsDNA antibody were at highest risk for pregnancy loss and preterm delivery in SLE1). It is unclear whether these problems are associated with the activity of underlying CTD or immunosuppressant treatment. Objectives We examine the issue of pregnancy and delivery complicated with CTD by the analysis of the cases in our institution. Methods We investigated the risk factors of preterm birth, LFD (light for dates) and perinatal complication from exacerbation of underlying disease, anti SS-A antibody, antiphospholipid antibody, doses of corticosteroid, immunosuppressants or biologics before pregnancy in 142 cases which were delivered in our institution. Results In 23 among all cases underlying diseases were exacerbated, and these occurred more often in PM/DM (60%), MCTD (33.3%), RA (15.3%) and SLE (13.3%). In SLE, SS, MCTD and PM/DM, preterm births and LFD were closely related to disease exacerbation and dose of corticosteroid, pulse therapy, and these were extracted as risk factors for these perinatal complications. Preterm birth was also associated with low complement (CH50) and high titer of anti-dsDNA antibody, and LFD was associated with high titer of anti-dsDNA antibody before pregnancy. However, there was no significant association with these factors in threatened premature delivery and PROM. In RA, perinatal complications were not influenced by methotrexate and biologics before pregnancy. However, only LFD was related with doses of corticosteroid during pregnancy. Conclusions We extracted disease exacerbation and dose of corticosteroid, pulse therapy during pregnancy and also low complement, high titer of anti-double stranded DNA antibody before pregnancy as risk factors of pregnancy outcomes. In pregnancy complicated with CTD, we need to control the disease activity strictly, however, we should consider the increase or pulse therapy of corticosteroid carefully. References Clowse ME, Maqder LS, et al. The clinical utility of measuring complement and anti-dsDNA antibodies during pregnancy in patients with systemic lupus erythematosus. J Rheumatol. 2011 Jun; 38(6):1012–6. Disclosure of Interest None declared

Objective Complement plays a major role in SLE. Complement participation has been linked to disease activity and damage. Our objective was to estimate the association of complement behaviour with clinical manifestations, visceral injury and mortality in patients with SLE. Methods Complement determinations (C3 and C4 levels) were analysed in patients with SLE (fulfilling American College of Rheumatology (ACR) or Systemic Lupus International Collaborating Clinics (SLICC)criteria) seen at a university hospital between 2000 and 2013. Patients were grouped in those with permanent C3 and/or C4 low values (low complement group), those with C3 and C4 constant normal values (normal complement group) and those with fluctuant values (periods of normal and periods of low values: fluctuant group). Clinical characteristics and mortality were analysed and compared between groups. Results 270 patients with SLE were included (242 females, 89.6%), mean age at diagnosis was 34.2 years (SD 15.8). 75 patients had fluctuant levels of complement, 79 patients had persistent low complement levels and 116 had normal complement levels. Lupus glomerulonephritis was more frequent in patients with fluctuant levels (75%, 56% and 49%, respectively, p=0002). The normal complement group had less frequency of haematological involvement and anti-double stranded DNA (dsDNA) antibodies. At the end of the follow-up, 53% of the patients had damage (SLICC/ACR ≥1). In a Cox proportional hazard model age at diagnosis, neurological impairment, thrombocytopaenia and corticosteroids were associated with more damage, while hydroxychloroquine was a protective factor. There were no differences between complements groups on accumulated damage. Ten-year survival rate was 93%, 93.5% and 92% for the normal complement group, the persistently low group and the fluctuant group, respectively. Conclusions Patients with constant normal complement had lower prevalence of haematological involvement and anti-dsDNA, while patients with fluctuant complement had higher renal impairment. Neither the persistent low complement nor the fluctuant complement groups had increased mortality and/or visceral damage.

Background Autoantibodies, low complement levels and higher NK cell counts are present in a subset of women with recurrent pregnancy loss (RPL). The combination of these abnormalities might be a surrogate profile for the presence of a subclinical inflammatory or autoimmune condition. Objectives In a cohort of women with unexplained RPL we evaluated if an immunological profile combining innate and adaptive immunity mediators was associated with the presence of distinct clinical characteristics that are commonly observed in autoimmune diseases and if it was a risk factor for developing these diseases. In a small subset of women with the immunological profile we evaluated the activation status of CD4+ and CD8+ cells. Methods We evaluated 366 women with RPL defined as 2 or more pregnancy losses and 93 control women. We defined the immune profile as the presence of 2 or more of the following abnormalities: Peripheral blood NK cell percentages >15%, positive antiphospholipid antibodies, positive antinuclear antibodies, positive anti-thyroid antibodies, low complement C3 levels and low C4 complement levels. Evolution to autoimmune diseases was detected during follow-up. Lymphocyte subsets were evaluated by flow-cytometry. Statistics: Chi-square test. Logistic regression. Results The prevalence of women with 2 or more immunological abnormalities was 57 out of 366 women (15.6%) and was significantly higher than in control women. Demographic clinical characteristics were similar in women with 2 or more immunological abnormalities as compared with women with only one immunological alteration or no abnormalities. The presence of the immunological profile was significantly associated with the presence of the following clinical characteristics: Leucopenia (p=0.048), lymphopenia (p=0.007), livedo reticularis (p=0.01), cutaneous rash (p=0.009), and arthritis (p=0.001). During follow-up 17 patients (4.6%) developed an inflammatory or autoimmune disease that was not present at the time of the diagnose of RPL including SLE and lupus like disease. Women with the immunological profile were at higher risk for evolution into these diseases: OR 4.19, 95% confidence interval 1.52–11.51, p=0.0055. In 10 women with the immunological profile we observed significantly higher levels of CD4+DR+ and CD8+DR+ T-cells as compared with women without the immune profile. Conclusions A subgroup of women with unexplained RPL are at risk of developing clinical characteristics of an inflammatory or autoimmune disease. In this regard, the immunological evaluation of women with RPL might be necessary not only to identify a potential cause of abortion but also to identify women that could require a more careful clinical follow-up. Higher CD4+DR+ and CD8+DR+ T-cells might be a pathogenic pathway leading to development of autoimmune diseases in RPL women. References Viallard JF, Bloch-Michel C, Neau-Cransac M, Taupin JL, Garrigue S, Miossec V, Mercie P, Pellegrin JL, Moreau JF. HLA-DR expression on lymphocyte subsets as a marker of disease activity in patients with systemic lupus erythematosus. Clin Exp Immunol. 2001;125(3):485–91. CD8+DR+ T-Cells and C3 Complement Serum Concentration as Potential Biomarkers in Thrombotic Antiphospholipid Syndrome. Sarmiento E, Dale J, Arraya M, Gallego A, Lanio N, Navarro J, Carbone J. Autoimmune Dis. 2014. Acknowledgements Research Funds. Fundacion Salud 2000. Madrid Spain. Disclosure of Interest None declared