Serologic immunogenicity and safety of Herpes Zoster subunit vaccine in patients with Rheumatoid Arthritis receiving Janus Kinase inhibitors.

OBJECTIVE: Patients with rheumatoid arthritis (RA) treated with Janus Kinase inhibitors (JAKi) are at increased risk of Herpes Zoster (HZ). The objective of this study was to investigate serological immunogenicity and safety of the HZ subunit (HZ/su) vaccine in RA patients treated with JAKi, for which little is known. METHODS: RA patients treated with JAKi (n = 82) at the Department of Rheumatology, Skåne University Hospital, Sweden, and healthy controls (n = 51) received two doses of the HZ/su vaccine (Shingrix). Vaccine-specific antibody responses were analysed using indirect enzyme-linked immunosorbent assay (ELISA). Post-vaccination antibody levels were compared between patients and controls using analysis of covariance. Potential predictors for vaccine response were investigated using a multivariable linear regression analysis. Self-reported adverse events (AEs) and changes in RA disease activity were analysed. RESULTS: Following vaccination, vaccine-specific antibody levels increased significantly in both patients and controls (p< 0.0001). 80.5% of patients and 98.0% of controls achieved a ≥ 4-fold increase in antibody levels. Post-vaccination antibody levels were lower in patients than controls (ratio 0.44, 95% CI 0.31-0.63), and lower in patients receiving JAKi+Methotrexate than JAKi monotherapy (ratio 0.43, 95% CI 0.24-0.79). AEs, mostly mild/moderate, were common. One patient developed HZ and six patients (6.5%) had increased RA disease activity following vaccination. CONCLUSION: The HZ/su vaccine was serologically immunogenic in most RA patients treated with JAKi. Moreover, the vaccine had an acceptable safety profile. These results support recommendations for usage of the HZ/su vaccine in this vulnerable population. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT03886038.

Plasma and cerebrospinal fluid neurofilament light concentrations reflect neuronal damage in systemic lupus Erythematosus.

BACKGROUND: Neuronal damage in systemic lupus erythematosus (SLE) is common, but the extent and mechanisms are unclear. Neurofilament light (NfL) concentrations rise in plasma and cerebrospinal fluid (CSF) during neuronal damage in various neurological disorders. In this cross-sectional study, plasma and CSF concentrations of NfL were explored as a marker of neuronal damage in SLE. METHODS: Seventy-two consecutive SLE out-patients and 26 healthy controls, all female, aged < 55 years, underwent magnetic resonance imaging (MRI) and neurocognitive testing. NfL concentrations in plasma from all individuals and in CSF from 32 patients were measured with single-molecule array technology. Patients were assessed by a rheumatologist and neurologist to define neuropsychiatric involvement (NPSLE) according to three attribution models: SLICC A, SLICC B and ACR. RESULTS: Plasma and CSF NfL concentrations correlated strongly (r = 0.72, p < 0.001). Both NPSLE and non-NPSLE patients in all attribution models had higher plasma NfL concentrations compared with healthy controls (log-NfL, pg/ml, mean (SD); healthy controls (0.71 (0.17)); SLICC A model: NPSLE (0.87 (0.13), p = 0.003), non-NPSLE (0.83 (0.18), p = 0.005); SLICC B model: NPSLE (0.87 (0.14), p = 0.001), non-NPSLE (0.83 (0.18), p = 0.008); ACR model: NPSLE (0.86 (0.16), p < 0.001), non-NPSLE (0.81 (0.17), p = 0.044)). Plasma and CSF NfL concentrations did not differ between NPSLE and non-NPSLE patients. Higher plasma NfL concentrations correlated with larger CSF volumes on MRI (r = 0.34, p = 0.005), and was associated with poorer cognitive performance in the domains of simple attention, psychomotor speed and verbal memory. SLICC/ACR-Damage Index ≥1 was independently associated with higher plasma NfL concentrations (ß = 0.074, p = 0.038). Higher plasma creatinine concentrations, anti-dsDNA-positivity, low complement C3 levels, or a history of renal involvement were associated with higher plasma NfL concentrations (ß = 0.003, p = 0.009; ß = 0.072, p = 0.031; ß = 0.077, p = 0.027; ß = 0.069, p = 0.047, respectively). CONCLUSIONS: Higher plasma NfL concentrations in NPSLE and non-NPSLE patients may indicate a higher degree of neuronal damage in SLE in general, corresponding to cognitive impairment and organ damage development. Furthermore, our results may indicate a higher degree of neuronal breakdown in patients with active SLE, also without overt clinical symptoms. NfL may serve as an indicator of neuronal damage in SLE in further studies.

A single nucleotide polymorphism in the NCF1 gene leading to reduced oxidative burst is associated with systemic lupus erythematosus.

OBJECTIVES: Ncf1 polymorphisms leading to low production of reactive oxygen species (ROS) are strongly associated with autoimmune diseases in animal models. The human NCF1 gene is very complex with both functional and non-functional gene copies and genotyping requires assays specific for functional NCF1 genes. We aimed at investigating association and function of the missense single nucleotide polymorphism (SNP), rs201802880 (here denoted NCF1-339) in NCF1 with systemic lupus erythematosus (SLE). METHODS: We genotyped the NCF1-339 SNP in 973 Swedish patients with SLE and 1301 controls, using nested PCR and pyrosequencing. ROS production and gene expression of type 1 interferon-regulated genes were measured in isolated cells from subjects with different NCF1-339 genotypes. RESULTS: We found an increased frequency of the NCF1-339 T allele in patients with SLE, 11% compared with 4% in controls, OR 3.0, 95% CI 2.4 to 3.9, p=7.0×10-20. The NCF1-339 T allele reduced extracellular ROS production in neutrophils (p=0.004) and led to an increase expression of type 1 interferon-regulated genes. In addition, the NCF1-339 T allele was associated with a younger age at diagnosis of SLE; mean age 30.3 compared with 35.9, p=2.0×1-6. CONCLUSIONS: These results clearly demonstrate that a genetically controlled reduced production of ROS increases the risk of developing SLE and confirm the hypothesis that ROS regulate chronic autoimmune inflammatory diseases.

Decreased platelet size is associated with platelet activation and anti-phospholipid syndrome in systemic lupus erythematosus.

Objectives: . SLE is an autoimmune disease with increased cardiovascular morbidity and platelet activation. In the general population, increased platelet size predicts platelet reactivity and cardiovascular disease. The aim of this study was to investigate whether platelet size related to platelet activation and cardiovascular disease in SLE. Methods: . Fresh blood samples from SLE patients ( n = 148), healthy volunteers ( n = 79) and disease controls ( n = 40) were analysed for platelet size and activation by flow cytometry, ELISA and cell count. Associations to manifest cardiovascular disease, venous thrombosis and APS were adjusted for traditional cardiovascular risk factors using logistic regression analysis. Results: . SLE patients had decreased platelet size as compared with healthy controls ( P = 0.003). In SLE, decreased platelet size was related to increased platelet activation, in particular microparticle formation ( P < 0.0001, r = -0.46) and release of serotonin from dense granules ( P < 0.001, r = 0.57). SLE patients with aCL had decreased platelet size ( P = 0.02) and aCL decreased platelet size in vitro ( P = 0.007). In contrast to the general population, increased platelet size was not associated with cardiovascular disease. Instead, decreased platelet size was associated with secondary APS, even after adjusting for traditional cardiovascular risk factors ( P = 0.01, odds ratio 3.58). Conclusion: . Platelet size is decreased in SLE patients and associated with microparticle formation and APS. Future studies are needed to determine the underlying mechanism(s) as well as the potential predictive value of small platelets for disease complications in SLE.

Circulating complexes between tumour necrosis factor-alpha and etanercept predict long-term efficacy of etanercept in juvenile idiopathic arthritis.

AIM: The relationship between tumour necrosis factor-alpha (TNF-α) and drug survival had not been studied in juvenile idiopathic arthritis (JIA), and there were no laboratory tests to predict the long-term efficacy of biological drugs for JIA. We studied whether serum levels of TNF-α, free or bound to etanercept, could predict long-term efficacy of etanercept in children with JIA. METHODS: We included 41 biologic-naïve patients with JIA who started treatment with etanercept at Skåne University Hospital between 1999 and 2010. Serum taken at the start of treatment and at the six-week follow-up were analysed for TNF-α and the long-term efficacy of etanercept was assessed using the drug survival time. RESULTS: Levels of TNF-α increased significantly at the six-week follow-up, and this was almost exclusively comprised of TNF-α in complex with etanercept. The increase in TNF-α showed a dose-dependent correlation to long-term drug survival (p < 0.01). CONCLUSION: Increasing levels of circulating TNF-α at treatment initiation predicted long-term efficacy of etanercept in children with JIA, which may have been due to different pathophysiological mechanisms of inflammation. Our result may provide a helpful clinical tool, as high levels of circulating TNF-α/etanercept complexes could be used as a marker for the long-term efficacy of etanercept.

Serum from patients with systemic vasculitis induces alternatively activated macrophage M2c polarization.

Anti-neutrophil cytoplasmic antibody associated vasculitides (AAV) are conditions defined by an autoimmune small vessel inflammation. Dying neutrophils are found around the inflamed vessels and the balance between infiltrating neutrophils and macrophages is important to prevent autoimmunity. Here we investigate how sera from AAV patients may regulate macrophage polarization and function. Macrophages from healthy individuals were differentiated into M0, M1, M2a, M2b or M2c macrophages using a standardized protocol, and phenotyped according to their expression surface markers and cytokine production. These phenotypes were compared with those of macrophages stimulated with serum from AAV patients or healthy controls. While the healthy control sera induced a M0 macrophage, AAV serum promoted polarization towards the M2c subtype. No sera induced M1, M2a or M2b macrophages. The M2c subtype showed increased phagocytosis capacity compared with the other subtypes. The M2c polarization found in AAV is consistent with previous reports of increased levels of M2c-associated cytokines.

Neutrophil extracellular traps that are not degraded in systemic lupus erythematosus activate complement exacerbating the disease.

Ongoing inflammation including activation of the complement system is a hallmark of systemic lupus erythematosus (SLE). Antimicrobial neutrophil extracellular traps (NETs) are composed of secreted chromatin that may act as a source of autoantigens typical for SLE. In this study, we investigated how complement interacts with NETs and how NET degradation is affected by complement in SLE patients. We found that sera from a subset of patients with active SLE had a reduced ability to degrade in vitro-generated NETs, which was mostly restored when these patients were in remission. Patients that failed to degrade NETs had a more active disease and they also displayed lower levels of complement proteins C4 and C3 in blood. We discovered that NETs activated complement in vitro and that deposited C1q inhibited NET degradation including a direct inhibition of DNase-I by C1q. Complement deposition on NETs may facilitate autoantibody production, and indeed, Abs against NETs and NET epitopes were more pronounced in patients with impaired ability to degrade NETs. NET-bound autoantibodies inhibited degradation but also further increased C1q deposition, potentially exacerbating the disease. Thus, NETs are a potent complement activator, and this interaction may play an important role in SLE. Targeting complement with inhibitors or by removing complement activators such as NETs could be beneficial for patients with SLE.

Increased serum levels of S100A8/A9 and S100A12 are associated with cardiovascular disease in patients with inactive systemic lupus erythematosus.

OBJECTIVES: Patients with SLE have an increased morbidity and mortality from cardiovascular disease (CVD). The reason for this is not entirely understood, but is believed to be partly related to the long-lasting inflammatory process seen in SLE. The aim of the present study was to investigate whether there is an association between CVD and serum levels of the proinflammatory proteins S100A8/A9 and S100A12 in SLE. METHODS: Serum levels of S100A8/A9 and S100A12 were measured with ELISA in 237 SLE patients with clinically inactive disease and without infections, as well as in 100 healthy individuals. Cardiovascular manifestations were defined according to the SLICC/ACR Damage Index (SLICC/ACR-DI). RESULTS: Serum levels of S100A8/A9 were elevated in our inactive SLE patients as compared with healthy individuals (P < 0.0001), which was not seen for S100A12 (P = 0.12). SLE patients with a history of CVD had increased serum levels of both S100A8/A9 and S100A12 compared with patients with no CVD or venous thromboembolism (P = 0.003 and P = 0.006, respectively). The presence of organ damage according to SLICC/ACR-DI was associated with an increase in both S100A8/A9 and S100A12 serum levels (P = 0.001 and P = 0.006, respectively). CONCLUSION: Elevated serum levels of S100A8/A9 and S100A12 may be used as an indicator of severe disease and CVD in SLE, suggesting that SLE patients with elevated serum S100A8/A9 and S100A12 concentrations may benefit from more intense cardiovascular primary preventive strategies and possibly also from more intense and early immunosuppressive treatment.

Increased IgG on cell-derived plasma microparticles in systemic lupus erythematosus is associated with autoantibodies and complement activation.

OBJECTIVE: To quantify immunoglobulin and C1q on circulating cell-derived microparticles (MPs) in patients with systemic lupus erythematosus (SLE) and to determine whether immunoglobulin and C1q levels are correlated with clinical and serologic parameters. METHODS: Sixty-eight clinically well-characterized SLE patients, 38 healthy controls, 6 patients with systemic sclerosis (SSc), and 6 patients with rheumatoid arthritis (RA) were included. The numbers of annexin V-binding MPs displaying IgG, IgM, or C1q were enumerated by flow cytometry. MP protein levels were determined by mass spectrometry in clinically defined subsets of SLE patients and controls. The MP IgG load was determined by flow cytometric analysis of all samples from SLE patients and healthy controls. RESULTS: SLE patients had significantly increased total and relative numbers of IgG-positive MPs (P = 0.0004), with a much higher average IgG load per MP (P < 0.0001) than healthy controls. Quantitative mass spectrometry of purified MPs verified significantly increased IgG, IgM, and C1q levels in SLE patients. In RA and SSc patients, the average IgG load per MP was significantly lower than in SLE patients (P = 0.006 and P = 0.05, respectively). Also, the IgM load and C1q load per MP were significantly higher in SLE patients than in the control groups (P < 0.05), except for IgM in the RA group. IgG-positive MPs were significantly associated with the presence of anti-double-stranded DNA, anti-extractable nuclear antigen, and antihistone antibodies, with total IgG, and with decreased leukocyte counts. Average IgG load per MP was associated with lower concentrations of MPs, the presence of anti-C1q antibodies, and complement consumption. CONCLUSION: Our findings indicate that circulating cell-derived MPs in SLE patients carry increased loads of IgG, IgM, and C1q and that IgG MPs are associated with autoantibodies and complement activation. The findings link immunologic reactions on MPs with the etiology of SLE.

IgG glycan hydrolysis by endoglycosidase S diminishes the proinflammatory properties of immune complexes from patients with systemic lupus erythematosus: a possible new treatment?

OBJECTIVE: Systemic lupus erythematosus (SLE) is an autoimmune disease with chronic or episodic inflammation in several organ systems, related to the presence of circulating and tissue-deposited immune complexes (ICs) that stimulate leukocytes through Fcγ receptors (FcγR) with subsequent inflammation. Treatment with endoglycosidase S (EndoS), an IgG glycan-hydrolyzing bacterial enzyme from Streptococcus pyogenes, has shown beneficial effects in several experimental animal models of chronic inflammatory disease. This study was undertaken to investigate whether EndoS affects the proinflammatory properties of ICs and has the potential to be developed as a therapy for SLE. METHODS: ICs purified from SLE patients or RNA-containing ICs formed in vitro were treated with EndoS and used in several assays reflecting different important features of SLE pathogenesis, such as phagocytosis by polymorphonuclear cells (PMNs) and plasmacytoid dendritic cells (PDCs), complement activation, and interferon-α (IFNα) production by PDCs. RESULTS: EndoS treatment abolished all proinflammatory properties of the ICs investigated. This included FcγR-mediated phagocytosis by PDCs (P = 0.001) and subsequent production of IFNα (P = 0.002), IC-induced classical pathway of complement activation (P = 0.008), chemotaxis, and oxidative burst activity of PMNs (P = 0.002). EndoS treatment also had a direct effect on the molecular structure of ICs, causing decreased IC size and glycosylation. CONCLUSION: Our findings indicate that EndoS treatment has prominent effects on several pathogenetically important IC-mediated events, and suggest that EndoS has the potential to be developed as a novel therapy for SLE.

A candidate gene approach to ANCA-associated vasculitis reveals links to the C3 and CTLA-4 genes but not to the IL1-Ra and Fcγ-RIIa genes.

BACKGROUND/AIMS: The aim of the study is to search for associations between Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) and polymorphisms in the genes of four key molecules possibly involved in different pathogenic pathways; complement C3, CTLA-4, Fcγ-RIIa and IL1-Ra. PATIENTS AND METHODS: Patients with AAV (n=105) subgrouped as microscopic polyangiitis or granulomatosis with polyangiitis (Wegener's granulomatosis) and myeloperoxidase (MPO) or proteinase 3 (PR3) ANCA positive were compared to a control group of 200 blood donors. Polymorphisms in the genes were analysed with PCR amplification of DNA. RESULTS: The diagnosis of AAV was confirmed in the 105 cases. The gene frequency of C3F was 0.27 in the PR3-ANCA subgroup (p=0.041) compared to 0,19 in the control group. The number of patients homozygous for the shortest 86 bp allele of CTLA-4 was significantly decreased in the whole group of patients (p=0.049). No differences were evident in the Fcγ-RIIa and IL1-Ra polymorphisms when compared to controls, neither in the whole group of patients, nor in any of the sub-groups. CONCLUSION: The aberrant gene frequency of the C3F allele among PR3-ANCA positive patients and the findings with the CTLA-4 polymorphism indicates that complement may be involved in pathogenesis and that T-cell activation also is of importance in these diseases.

Vaccination against encapsulated bacteria in hereditary C2 deficiency results in antibody response and opsonization due to antibody-dependent complement activation.

Hereditary C2 deficiency (C2D) is an important susceptibility factor for invasive infections caused by encapsulated bacteria such as pneumococci and Haemophilus influenzae type b. The infections are mostly seen in childhood indicating that antibody-mediated acquired immunity is affected. C2D persons and healthy controls were vaccinated with ActHIB® and Pneumo23®. Analysis of specific antibodies to pneumococci serotype 6B, 7F, and 23F, and Hib was performed. Post-vaccination IgG antibodies against pneumococci serotype 6B and 23F at a concentration ≥1.0mg/L was found in similar frequency in C2D persons and controls. Post-vaccination sera from C2D persons showed poor complement-mediated opsonization and phagocytosis of pneumococci by granulocytes when depending on classical and lectin pathway activation only, but increased (p=0.007) and equaled that of the normal controls when also alternative pathway activation was allowed due to antibody-dependent C2 bypass activation. In conclusion, the C2D persons benefited from the vaccination and achieve an increased phagocytic capacity.

Platelet transcriptional profile and protein expression in patients with systemic lupus erythematosus: up-regulation of the type I interferon system is strongly associated with vascular disease.

Patients with systemic lupus erythematosus (SLE) have a markedly increased risk to develop cardiovascular disease, and traditional cardiovascular risk factors fail to account for this increased risk. We used microarray to probe the platelet transcriptome in patients with SLE and healthy controls, and the gene and protein expression of a subset of differentially expressed genes was further investigated and correlated to platelet activation status. Real-time PCR was used to confirm a type I interferon (IFN) gene signature in patients with SLE, and the IFN-regulated proteins PRKRA, IFITM1 and CD69 (P < .0001) were found to be up-regulated in platelets from SLE patients compared with healthy volunteers. Notably, patients with a history of vascular disease had increased expression of type I IFN-regulated proteins as well as more activated platelets compared with patients without vascular disease. We suggest that interferogenic immune complexes stimulate production of IFNα that up-regulates the megakaryocytic type I IFN-regulated genes and proteins. This could affect platelet activation and contribute to development of vascular disease in SLE. In addition, platelets with type I IFN signature could be a novel marker for vascular disease in SLE.

Serum S100A8/A9 concentrations are associated with neuropsychiatric involvement in systemic lupus erythematosus: a cross-sectional study.

BACKGROUND: Neuropsychiatric (NP) involvement and fatigue are major problems in systemic lupus erythematosus (SLE). S100A8/A9 is a marker of inflammation and responds to therapy in SLE patients. S100A8/A9 has an immunopathogenic role in various neurological diseases. We investigated S100A8/A9 in relation to NP-involvement and fatigue in SLE. METHODS: 72 consecutive SLE outpatients at a tertiary centre and 26 healthy controls were included in this cross-sectional study. NPSLE was determined by specialists in rheumatology and neurology and defined according to three attribution models: "ACR", "SLICC A" and "SLICC B". Cerebral MRI was assessed by a neuroradiologist and neurocognitive testing by a neuropsychologist. The individuals were assessed by scores of pain (VAS), fatigue (VAS and FSS), and depression (MADRS-S). Concentrations of S100A8/A9 in serum and cerebrospinal fluid were measured with ELISA. Statistical calculations were performed using non-parametric methods. RESULTS: Serum concentrations of S100A8/A9 were higher in SLE patients compared with controls (medians 1230 ng/ml; 790 ng/ml, p = 0.023). The concentrations were higher in NPSLE patients compared with non-NPSLE patients when applying the SLICC A and ACR models, but not significant when applying the SLICC B model (medians 1400 ng/ml; 920 ng/ml, p = 0.011; 1560 ng/ml; 1090 ng/ml, p = 0.050; 1460 ng/ml; 1090 ng/ml, p = 0.083, respectively). No differences of CSF S100A8/A9 concentrations were observed between NPSLE and non-NPSLE patients. SLE patients with depression or cognitive dysfunction as an ACR NPSLE manifestation had higher serum S100A8/A9 concentrations than non-NPSLE patients (median 1460 ng/ml, p = 0.007 and 1380 ng/ml, p = 0.013, respectively). Higher serum S100A8/A9 correlated with higher VAS fatigue (r = 0.31; p = 0.008) and VAS pain (r = 0.27, p = 0.021) in SLE patients. Serum S100A8/A9 was not independently associated with NPSLE when adjusting for scores of fatigue (FSS) and pain (VAS) (OR 1.86, 95% CI 0.93-3.73, p = 0.08). CONCLUSIONS: Serum S100A8/A9 concentrations may be associated with NPSLE and fatigue. S100A8/A9 may be of interest in evaluating NPSLE, although further investigations are needed.

Enrichment of Complement, Immunoglobulins, and Autoantibody Targets in the Proteome of Platelets from Patients with Systemic Lupus Erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is a complex disease characterized by autoimmunity toward apoptotic cells, excessive amounts of circulating immune complexes, and complement activation. A decreased platelet size has been observed in SLE and their nonhemostatic functions may play an active role in the disease. The main objective of this study was to find clues that could explain their decreased size and functional role, analyzing the entire platelet proteome. METHODS: Platelets were isolated from 23 patients with SLE. The five individuals with the highest and lowest average platelet forward scatter were selected for further analysis. Platelet protein content was analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and compared with platelets from five healthy controls. Data are available via ProteomeXchange with identifier PXD031202. RESULTS: Out of 2,572 proteins identified, 396 had significantly different levels (ANOVA q-value ≤ 0.01). Forty proteins, including immunoglobulin-, complement- and phosphatidylserine-binding proteins had higher abundance in platelets from SLE patients, largely independent of size (fold difference of ≥1.5 and a t-test p-value of ≤0.05 as cut-off). Functional characterization revealed increased degranulation and skewed hemostatic balance in platelets from SLE patients. In the SLE proteome, immunoglobulin proteins were negatively correlated to serum complement C3 and C4 and the highest relative levels were detected in platelets of normal size. CONCLUSION: Platelets from SLE patients shared a specific protein profile, including immunoglobulins, complement proteins, and autoantigens, largely independent of the platelet size and in agreement with an integrated role for platelets in SLE.

Increased serum bactericidal activity of autologous serum in C2 deficiency after vaccination against Haemophilus influenzae type b, and further support for an MBL-dependent C2 bypass mechanism.

Deficiencies of C2 and other components of the classical pathway of complement are associated with increased risk of infections with encapsulated bacteria, such as Haemophilus (H.) influenzae. Defense against H. influenzae is dependent on specific antibodies and complement, which mediate serum bactericidal activity (SBA) and opsonization. Due to lack of normal classical and lectin complement pathway function in C2 deficiency (C2D), SBA would have to depend either on the alternative pathway or on C2 bypass mechanisms. Here we studied SBA against H. influenzae type b (Hib) before and after vaccination in a group of C2-deficient persons, as the bactericidal capacity of antibodies in autologous complement in relation to vaccination has not been investigated at group level in C2D. Sera from 22 persons with C2D and 26 healthy controls were available. Out of these, 18 persons with C2D and all controls had been vaccinated with Act-HIB®. SBA against Hib bacteria was analyzed with autologous serum as the only complement source. Antibodies to Hib capsular polysaccharide had been analyzed previously. Concentrations of mannose-binding lectin (MBL) and other complement components were measured in serum. SBA of both C2-deficient persons and controls was significantly more efficient after vaccination (p = 0.002 and p < 0.0001, respectively). After vaccination, all but two C2-deficient sera and one control serum showed sufficient SBA (<50% surviving bacteria). Before vaccination, SBA of C2-deficient sera was negatively correlated to serum concentrations of MBL (lower proportion of surviving bacteria with higher MBL concentration; r = -0.55, p = 0.008). After vaccination, SBA of C2-deficient sera was negatively correlated to serum concentrations of IgG Hib antibodies (r = -0.56, p = 0.01). In conclusion, SBA against Hib in autologous serum is increased after vaccination in persons with C2D. In unvaccinated C2-deficient persons SBA was correlated to MBL concentration, providing further support for an MBL-dependent C2 bypass mechanism operating in C2D.

Mismatch between circulating cytokines and spontaneous cytokine production by leukocytes in hyperinflammatory COVID-19.

The disease COVID-19 has developed into a worldwide pandemic. Hyperinflammation and high levels of several cytokines, for example, IL-6, are observed in severe COVID-19 cases. However, little is known about the cellular origin of these cytokines. Here, we investigated whether circulating leukocytes from patients with COVID-19 had spontaneous cytokine production. Patients with hyperinflammatory COVID-19 (n = 6) and sepsis (n = 3) were included at Skåne University Hospital, Sweden. Healthy controls were also recruited (n = 5). Cytokines were measured in COVID-19 and sepsis patients using an Immulite immunoassay system. PBMCs were cultured with brefeldin A to allow cytokine accumulation. In parallel, LPS was used as an activator. Cells were analyzed for cytokines and surface markers by flow cytometry. High levels of IL-6 and measurable levels of IL-8 and TNF, but not IL-1ß, were observed in COVID-19 patients. Monocytes from COVID-19 patients had spontaneous production of IL-1ß and IL-8 (P = 0.0043), but not of TNF and IL-6, compared to controls. No spontaneous cytokine production was seen in lymphocytes from either patients or controls. Activation with LPS resulted in massive cytokine production by monocytes from COVID-19 patients and healthy controls, but not from sepsis patients. Finally, monocytes from COVID-19 patients produced more IL-1ß than from healthy controls (P = 0.0087) when activated. In conclusion, monocytes contribute partly to the ongoing hyperinflammation by production of IL-1ß and IL-8. Additionally, they are responsive to further activation. This data supports the notion of IL-1ß blockade in treatment of COVID-19. However, the source of the high levels of IL-6 remains to be determined.

Synovial fluid neutrophils in oligoarticular juvenile idiopathic arthritis have an altered phenotype and impaired effector functions.

BACKGROUND: Neutrophils are the most prevalent immune cells in the synovial fluid in inflamed joints of children with oligoarticular juvenile idiopathic arthritis (JIA). Despite this, little is known about neutrophil function at the site of inflammation in JIA and how local neutrophils contribute to disease pathogenesis. This study aimed to characterize the phenotype and function of synovial fluid neutrophils in oligoarticular JIA. METHODS: Neutrophils obtained from paired blood and synovial fluid from patients with active oligoarticular JIA were investigated phenotypically (n = 17) and functionally (phagocytosis and oxidative burst, n = 13) by flow cytometry. In a subset of patients (n = 6), blood samples were also obtained during inactive disease at a follow-up visit. The presence of CD206-expressing neutrophils was investigated in synovial biopsies from four patients by immunofluorescence. RESULTS: Neutrophils in synovial fluid had an activated phenotype, characterized by increased CD66b and CD11b levels, and most neutrophils had a CD16hi CD62Llowaged phenotype. A large proportion of the synovial fluid neutrophils expressed CD206, a mannose receptor not commonly expressed by neutrophils but by monocytes, macrophages, and dendritic cells. CD206-expressing neutrophils were also found in synovial tissue biopsies. The synovial fluid neutrophil phenotype was not dependent on transmigration alone. Functionally, synovial fluid neutrophils had reduced phagocytic capacity and a trend towards impaired oxidative burst compared to blood neutrophils. In addition, the effector functions of the synovial fluid neutrophils correlated negatively with the proportion of CD206+ neutrophils. CONCLUSIONS: Neutrophils in the inflamed joint in oligoarticular JIA were altered, both regarding phenotype and function. Neutrophils in the synovial fluid were activated, had an aged phenotype, had gained monocyte-like features, and had impaired phagocytic capacity. The impairment in phagocytosis and oxidative burst was associated with the phenotype shift. We speculate that these neutrophil alterations might play a role in the sustained joint inflammation seen in JIA.

Low Intra-Individual Variation in Mean Platelet Volume Over Time in Systemic Lupus Erythematosus.

Platelets have recently emerged as important immune modulators in systemic lupus erythematosus (SLE), in addition to their role in thrombosis and cardiovascular disease. However, studies investigating mean platelet volume (MPV) in SLE are often scarce, conflicting and cross-sectional. In this study, MPV was measured in clinical routine throughout a defined time-period to quantify both individual MPV fluctuations and investigate if such variations are associated with disease activity and clinical phenotypes of SLE. Of our 212 patients, 34 patients had only one MPV value reported with the remaining 178 patients having between 2 and 19 visits with recorded MPV values. The intra-individual MPV variation was low, with a median variation of 0.7 fL. This was further supported by the finding that 84% of patients stayed within their reference interval category (i.e., small, normal or large) over time. In our cohort, no correlation between disease activity and MPV neither cross-sectionally nor longitudinally was found. Mean platelet volume values were significantly smaller in SLE patients (mean 10.5 fL) compared to controls (mean 10.8 fL), p < 0.0001. Based on the reference interval, 2.4% (n = 5) of patients had large-sized platelets, 84.4% (n = 179) had normal-sized and 13.2% (n = 28) had small-sized. A larger proportion (85.7%) of patients with small-sized platelets met the anti-dsDNA criterion (ACR10b; p = 0.003) compared to patients with normal and large (57.6%) sized platelets. In conclusion, the intra-individual MPV variation was of low magnitude and fluctuations in disease activity did not have any significant impact on MPV longitudinally. This lack of variability in MPV over time indicates that measuring MPV at any time-point is sufficient. Further studies are warranted to evaluate MPV as a possible biomarker in SLE, as well as to determine the underlying mechanisms influencing platelet size in SLE.

Comparison of Surrogate Markers of the Type I Interferon Response and Their Ability to Mirror Disease Activity in Systemic Lupus Erythematosus.

Objectives: Type I interferons (IFNs) are central and reflective of disease activity in systemic lupus erythematosus (SLE). However, IFN-α levels are notoriously difficult to measure and the type I IFN gene signature (IGS) is not yet available in clinical routine. This study evaluates galectin-9 and an array of chemokines/cytokines in their potential as surrogate markers of type I IFN and/or SLE disease activity. Methods: Healthy controls and well-characterized Swedish SLE patients from two cross-sectional cohorts (n=181; n=59) were included, and a subgroup (n=21) was longitudinally followed. Chemokine/cytokine responses in immune complex triggered IFN-α activity was studied in healthy donor peripheral blood mononuclear cells (PBMC). Levels of chemokines/cytokines and galectin-9 were measured by immunoassays. Gene expression was quantified by qPCR. Results: The IGS was significantly (p<0.01) correlated with galectin-9 (rho=0.54) and CXCL10 (rho=0.37) levels whereas serum IFN-α correlated with galectin-9 (rho=0.36), CXCL10 (rho=0.39), CCL19 (rho=0.26) and CCL2 (rho=0.19). The strongest correlation was observed between galectin-9 and TNF (rho=0.56). IFN-α and disease activity (SLEDAI-2K) were correlated (rho=0.20) at cross-sectional analysis, but no significant associations were found between SLEDAI-2K and galectin-9 or chemokines. Several inflammatory mediators increased at disease exacerbation although CCL19, CXCL11, CXCL10, IL-10 and IL-1 receptor antagonist were most pronounced. Immune complex-stimulation of PBMC increased the production of CCL2, CXCL8 and TNF. Conclusion: Galectin-9 and CXCL10 were associated with type I IFN in SLE but correlated stronger with TNF. None of the investigated biomarkers showed a convincing association with disease activity, although CXCL10 and CCL19 performed best in this regard.