Dynamics of magnetization at infinite temperature in a Heisenberg spin chain

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Optimizing quantum gates towards the scale of logical qubits

A foundational assumption of quantum error correction theory is that quantum gates can be scaled to large processors without exceeding the error-threshold for fault tolerance. Two major challenges that could become fundamental roadblocks are manufacturing high-performance quantum hardware and engineering a control system that can reach its performance limits. The control challenge of scaling quantum gates from small to large processors without degrading performance often maps to non-convex, high-constraint, and time-dynamic control optimization over an exponentially expanding configuration space. Here we report on a control optimization strategy that can scalably overcome the complexity of such problems. We demonstrate it by choreographing the frequency trajectories of 68 frequency-tunable superconducting qubits to execute single- and two-qubit gates while mitigating computational errors. When combined with a comprehensive model of physical errors across our processor, the strategy suppresses physical error rates by ~3.7× compared with the case of no optimization. Furthermore, it is projected to achieve a similar performance advantage on a distance-23 surface code logical qubit with 1057 physical qubits. Our control optimization strategy solves a generic scaling challenge in a way that can be adapted to a variety of quantum operations, algorithms, and computing architectures.

Model-Based Optimization of Superconducting Qubit Readout

Measurement is an essential component of quantum algorithms, and for superconducting qubits it is often the most error prone. Here, we demonstrate model-based readout optimization achieving low measurement errors while avoiding detrimental side effects. For simultaneous and midcircuit measurements across 17 qubits, we observe 1.5% error per qubit with a 500 ns end-to-end duration and minimal excess reset error from residual resonator photons. We also suppress measurement-induced state transitions achieving a leakage rate limited by natural heating. This technique can scale to hundreds of qubits and be used to enhance the performance of error-correcting codes and near-term applications.

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the 'arrow of time' that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11-13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.

Non-Abelian braiding of graph vertices in a superconducting processor

Indistinguishability of particles is a fundamental principle of quantum mechanics¹. For all elementary and quasiparticles observed to date-including fermions, bosons and Abelian anyons-this principle guarantees that the braiding of identical particles leaves the system unchanged^2,3. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions^4-8. Hence, it can change the observables of the system without violating the principle of indistinguishability. Despite the well-developed mathematical description of non-Abelian anyons and numerous theoretical proposals^9-22, the experimental observation of their exchange statistics has remained elusive for decades. Controllable many-body quantum states generated on quantum processors offer another path for exploring these fundamental phenomena. Whereas efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasiparticles, superconducting quantum processors allow for directly manipulating the many-body wavefunction by means of unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons^9,10, we implement a generalized stabilizer code and unitary protocol²³ to create and braid them. This allows us to experimentally verify the fusion rules of the anyons and braid them to realize their statistics. We then study the prospect of using the anyons for quantum computation and use braiding to create an entangled state of anyons encoding three logical qubits. Our work provides new insights about non-Abelian braiding and, through the future inclusion of error correction to achieve topological protection, could open a path towards fault-tolerant quantum computing.

Formation of robust bound states of interacting microwave photons

Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

Noise-resilient edge modes on a chain of superconducting qubits

Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with ℤ 2 parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.

Measurement and control of a superconducting quantum processor with a fully integrated radio-frequency system on a chip

We describe a digital microwave platform called Presto, designed for measurement and control of multiple quantum bits (qubits) and based on the third-generation radio-frequency system on a chip. Presto uses direct digital synthesis to create signals up to 9 GHz on 16 synchronous output ports, while synchronously analyzing responses on 16 input ports. Presto has 16 DC-bias outputs, four inputs and four outputs for digital triggers or markers, and two continuous-wave outputs for synthesizing frequencies up to 15 GHz. Scaling to a large number of qubits is enabled through deterministic synchronization of multiple Presto units. A Python application programming interface configures a firmware for synthesis and analysis of pulses, coordinated by an event sequencer. The analysis integrates template matching (matched filtering) and low-latency (184-254 ns) feedback to enable a wide range of multi-qubit experiments. We demonstrate Presto's capabilities with experiments on a sample consisting of two superconducting qubits connected via a flux-tunable coupler. We show single-shot readout and active reset of a single qubit; randomized benchmarking of single-qubit gates showing 99.972% fidelity, limited by the coherence time of the qubit; and calibration of a two-qubit iSWAP gate.

POS0458 ENRICHMENT OF COMPLEMENT, IMMUNOGLOBULINS, AND AUTOANTIBODY TARGETS IN THE PROTEOME OF PLATELETS FROM PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Background

Systemic Lupus Erythematosus (SLE) is characterized by autoimmunity towards apoptotic/necrotic cells, complement activation and excessive amounts of circulating immune complexes. Platelets are recognized as immune cells that interacts with innate and adaptive immune functions. They are activated in SLE patients and contribute to an increased susceptibility to thrombosis [1]. Decreased platelet size has been observed in patients with SLE [2], but the mechanism(s) remains unclear. In this study, we have analyzed the complete proteome of platelets with normal and decreased size from SLE patients and from healthy controls (HC).

Objectives

Our aim was to find clues that could explain the morphological differences observed in platelets from SLE patients and to better characterize the role of platelets in SLE.

Methods

We included 23 consecutive patients with SLE, median SLEDAI-2K score was 2, and 10 HC. Blood count, serum complement levels and the presence of antiphospholipid or dsDNA antibodies were analyzed in all patients. Platelet size (forward scatter) and activation status (CD154, PAC1, CD32, PAR1, CD62P and Annexin V) was determined using flow cytometry. The proteome of 10 platelet isolates from SLE (five with smallest and the five with largest average size) and five HC were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Data were analyzed using ANOVA, t-test, hierarchical cluster analysis, protein interactions using the STRING software and correlation analysis using spearman correlation.

Results

We identified a total of 2572 proteins from the platelet isolates. Out of the identified proteins, 396 had significantly different levels, meeting an ANOVA q-value ≤ 0.01. Pairwise t-test analysis, using a fold difference (FD) of ≥ 1.5 and a p-value of ≤ 0.05 as cut off reveled significant differences in the distribution of proteins between groups. Platelets of both SLE groups (small and normal sized) shared higher levels of forty proteins and twenty proteins were reduced, compared to HC. Cytoskeletal functions were overrepresentation in the group of reduced proteins, while proteins with higher levels in platelets from SLE patients included proteins associated with complement and autoantibody targets such as Beta-2-glycoprotein 1, Annexin A5, and Prothrombin. Platelets from SLE patients also shared an abundance in immunoglobulin proteins, with even greater accumulation in the normal sized platelets. SLE platelet heavy constant alpha 1 (r -0.85, p=0.003), heavy constant mu (r -0.64, p=0.05) and heavy constant gamma 3 (r -0.80, p=0.008) was inversely correlated with complement C4 in serum and heavy constant gamma 2 (r -0.648, p=0.049) with complement C3.

Conclusion

This study revealed an accumulation of complement proteins, immunoglobulins and known autoantigens in platelets from SLE patients compared to HC. The signature was largely independent of platelet size, but the enrichment of proteins involved in SLE pathogenesis indicates that the composition is influenced by SLE disease mechanisms. This was supported by the inverse correlation between platelet immunoglobulin and serum levels of complement protein C3 and C4. Platelets are known to interact with complement and express the low-affinity immunoglobulin gamma Fc region receptor IIA (CD32), suggesting a role in the clearance of immune complexes [3]. Future studies will have to determine if platelets play a role in the turnover of complement and immune complexes and the potential role of platelets as a source of autoantigens.

References

[1]Linge, P., et al., The non-haemostatic role of platelets in systemic lupus erythematosus. Nat Rev Rheumatol, 2018. 14(4): p. 195-213.

[2]Lood, C., et al., Decreased platelet size is associated with platelet activation and anti-phospholipid syndrome in systemic lupus erythematosus. Rheumatology (Oxford), 2017. 56(3): p. 408-416.

[3]Huang, Z.Y., et al., Human platelet FcgammaRIIA and phagocytes in immune-complex clearance. Mol Immunol, 2011. 48(4): p. 691-6.

Disclosure of Interests

Petrus Linge: None declared, Andreas Jern: None declared, Helena Tydén: None declared, Birgitta Gullstrand: None declared, Hong Yan: None declared, Charlotte Welinder: None declared, Robin Kahn: None declared, Andreas Jonsen Consultant of: Astra Zeneca and glaxosmithkline, John Semple: None declared, Anders Bengtsson: None declared.

POS0116 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 [1-2]. Neurofilament light (NfL) concentrations rise in plasma and cerebrospinal fluid (CSF) during neuronal damage and reach abnormal levels in various neurological disorders [3]. NfL is sparsely studied in SLE [4-7].

Objectives

To explore plasma and CSF concentrations of NfL in SLE patients and investigate the associations between NfL and nervous system involvement, including cognitive dysfunction, imaging findings on magnetic resonance imaging (MRI), laboratory and clinical abnormalities, and to compare the NfL levels of SLE patients with those present in healthy controls.

Methods

In this cross-sectional study, 72 consecutive SLE out-patients and 26 healthy controls, all female, aged <55 years, underwent 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.

Results

Plasma and CSF NfL concentrations correlated strongly (r=0.72, p<0.001). Plasma NfL concentrations were higher in SLE patients, both with and without neuropsychiatric involvement, compared with healthy controls (Figure 1A-D). Plasma and CSF NfL concentrations did not differ between NPSLE and non-NPSLE patients (Figure 1B-D). Larger white matter lesion volumes correlated with higher CSF NfL concentrations in patients aged 18-30 (rs=0.80, p=0.005). Higher plasma NfL concentrations correlated with lower simple attention scores (rs=-0.42, p=0.007), and were associated with dysfunction of psychomotor speed (p=0.012) and verbal memory (p=0.024). SLICC/ACR-Damage Index ≥1 was independently associated with higher plasma log-NfL concentrations when adjusting for age, SLE Disease Activity Index-2000 ≥1, low complement C3 levels, a history of renal involvement or anti-dsDNA, and ongoing treatment (β=0.080, 95% CI 0.009-0.15, p=0.028).

Figure 1.

Plasma log-NfL concentrations between groups. The intervals illustrate means and standard deviations.

Conclusion

Higher plasma NfL concentrations in NPSLE and non-NPSLE patients may indicate a higher degree of neuronal damage in SLE in general, particularly in the lower age group, corresponding with cognitive impairment and organ damage development. NfL may serve as an indicator of neuronal damage in SLE in further studies.

References

[1]Jeltsch-David H, Muller S (2014) Neuropsychiatric systemic lupus erythematosus: Pathogenesis and biomarkers. Nature Reviews Neurology 10:579–596

[2]Hanly JG, Walsh NMG, Sangalang V (1992) Brain pathology in systemic lupus erythematosus. Journal of Rheumatology 19:732–741

[3]Gaetani L, Blennow K, Calabresi P, et al (2019) Neurofilament light chain as a biomarker in neurological disorders. Journal of Neurology, Neurosurgery and Psychiatry 90

[4]Trysberg E, Nylen K, Rosengren LE, Tarkowski A (2003) Neuronal and Astrocytic Damage in Systemic Lupus Erythematosus Patients with Central Nervous System Involvement. Arthritis and Rheumatism 48:2881–2887.

[5]Tjensvoll AB, Lauvsnes MB, Zetterberg H, et al (2020) Neurofilament light is a biomarker of brain involvement in lupus and primary Sjögren’s syndrome. Journal of Neurology.

[6]Lauvsnes MB, Zetterberg H, Blennow K, et al (2021) Neurofilament light in plasma is a potential biomarker of central nervous system involvement in systemic lupus erythematosus. Journal of Neurology 1:1–11.

[7]Engel S, Boedecker S, Marczynski P, et al (2021) Association of serum neurofilament light chain levels and neuropsychiatric manifestations in systemic lupus erythematosus. Therapeutic Advances in Neurological Disorders 14:175628642110514.

Disclosure of Interests

None declared

OP0172 THE IMPACT OF IMMUNOMODULATING TREATMENT ON THE IMMUNOGENICITY OF COVID-19 VACCINES IN PATIENTS WITH IMMUNE-MEDIATED INFLAMMATORY RHEUMATIC DISEASES COMPARED TO HEALTHY CONTROLS. A SWEDISH NATIONWIDE STUDY (COVID19-REUMA)

Background

Initial studies on the immunogenicity of COVID-19 vaccines in patients with immune-mediated inflammatory rheumatic diseases (IRD) reported diminished antibody response in general, and particularly when treated with rituximab or abatacept (1). Additional data are needed, especially for patients with IRD and immunomodulatory treatments.

Objectives

To elucidate the antibody response after two doses of COVID-19 vaccine in patients with IRD treated with biologic or targeted synthetic disease modifying anti-rheumatic drugs (b/ts DMARDs) as monotherapy or combined with conventional synthetic DMARDS (csDMARDs).

Methods

Antibodies against two antigens representing Spike full length protein and Spike S1 and a Nucleocapsid C-terminal fragment (used to confirm previously COVID-19 infection) were measured in serum obtained before and after the second vaccination using a multiplex bead-based serology assay (2). Patients with IRD receiving immunomodulating treatment, followed at a rheumatology department and healthy individuals (controls) were recruited from five Swedish regions. Antibody positivity was classified as the signal passing an antigen specific cutoff based on the mean intensity signal of 12 selected negative pre-pandemic controls plus 6SD for Spike/S1 and 12SD for Nucleocapsid-C. Good vaccine response was defined as having antibodies over cut-off level for both spike antigens. Percentage of responders in each treatment group was compared to controls (Chi2 test). Predictors of antibody response were determined using logistic regression analysis.

Results

In total, 414 patients (320 RA/JIA/psoriatic arthritis/axial spondylarthritis, 60 systemic vasculitis and 32 other IRD) and 61 controls participated. Patients receiving rituximab (n=145; 65% female; mean age 65years), abatacept (n=21; 77% female; mean age 66 years), IL6 inhibitors (n=77; 74% female; mean age 64years), JAK-inhibitors (n=58; 75% female, mean age 53years), TNF-inhibitors (n=68; 66% female; mean age 44years;), IL17 inhibitors (n=42; 54% female; mean age 44years) and controls (n=61; 74% female, mean age 49years) were studied. Patients receiving IL6 inhibitor (81.0%), abatacept (43.8%) or rituximab (33.8%) had a significantly lower antibody response rate compared to controls (98.4%), further pronounced if combined with csDMARD (p<0.001) (Figure 1). In the adjusted logistic regression analysis, higher age, rituximab, abatacept, concomitant csDMARD but not IL6 inhibitors, concomitant prednisolone, or a vasculitis diagnosis, remained significant predictors of antibody response (Table 1). All vaccines were well tolerated. 14 (3.4%) patients reported an increased activity in their IRD following vaccination.

Conclusion

In this nationwide study including IRD patients receiving b/ts DMARDs a decreased immunogenicity of COVID-19 vaccines was observed in patients receiving rituximab, abatacept and to some extent IL-6 inhibitors. Concomitant csDMARD gave further attenuation. Patients on rituximab and abatacept should be prioritized for booster doses of COVID19 vaccine.

References

[1]Jena, et al. Response to SARS-CoV-2 vaccination in immune mediated inflammatory diseases: Systematic rev./meta-analysis. Autoim. Rev: 2021;102927

[2]Hober, et al. Systematic evaluation of SARS-CoV-2 antigens enables a highly specific and sensitive multiplex serol. C-19 assay. Clin Transl Im. 2021;10(7): e1312

Table 1.

Predictors of antibody response to COVID-19 vaccine

Rituximab-1.799<0.0010.170.07-0.42Abatacept-1.9710.0010.140.04-0.45IL6 inhibitor0.0230.9651.020.36-2.94Age (years)-0.0810.0000.920.89-0.96csDMARD-1.1270.0020.320.16-0.66Prednisolone (mg/day)-0.0640.2060.940.85-1.04

Frequency (%) of individuals with good antibody response to COVID-19 vaccine

Acknowledgements

Unrestricted research grants have been received från Roche and starting grants from the Swedish Rheumatism Association

Disclosure of Interests

Martina Frodlund Consultant of: Consultancy fees from AstraZeneca and GSK, Katerina Chatzidionysiou Consultant of: Consultancy fees from Eli Lilly, AbbVie and Pfizer, Anna Södergren: None declared, Eva Klingberg: None declared, Anders Bengtsson: None declared, Lars Klareskog Grant/research support from: Research grants from Pfizer, BMS, Affibody, Sonoma Biotherapeutics, Meliha C Kapetanovic: None declared

POS0255 PREDICTORS OF ANTIBODY RESPONSE TO COVID-19 VACCINE IN RITUXIMAB TREATED PATIENTS WITH INFLAMMATORY RHEUMATIC DISEASES. A SWEDISH NATIONWIDE STUDY (COVID19-REUMA)

Background

In line with other reports, our group showed that patients treated with rituximab had significant impaired antibody response compared to patients treated with other biologic and targeted and synthetic disease modifying anti-rheumatic drugs (csDMARD).

Objectives

To investigate predictors of response to COVID-19 vaccination (2 doses of mRNA vaccines, 2 doses of virus vector vaccines or combinations of these) in patients with inflammatory rheumatic diseases (IRD) treated with rituximab and controls.

Methods

Antibody levels to three antigens: Spike protein full length, Spike S1 and Nucleocapsid C-terminal fragment (to confirm previous COVID-19 infection) were measured in sera collected before vaccination and 2-12 weeks after the second vaccine using a multiplex bead-based serology assay. The antigen-specific cut-off was defined as the median fluorescence intensity signal plus 6x standard deviations across 12 pre-pandemic controls. A good vaccine response was defined as having antibodies over the cut-off level for both spike antigens. Proportion (%) responders was compared between patients and controls (Chi2 test).

Patients with IRD receiving last rituximab treatment within a mean (range) 193 (23-501) days before first vaccination participated. Individuals without IRD served as a control group. Predictors of a good vaccine response were explored using multivariate logistic regression analysis adjusted for age, sex, disease duration, diagnosis (systemic vasculitis/RA/JIA/other), concomitant csDMARD, rituximab dose and prednisolone dose. Hazard ratio (chanse) of a good antibody response in relation to time between the last rituximab treatment and vaccination was studied by Kaplan-Meier survival analysis.

Results

In total, 145 patients receiving rituximab and 61 controls were inclyded. Of these, 82 received rituximab as monotherapy (67% women; mean age 66 years, mean disease duration 13 years; 33% had RA/JIA and 60% vasculitis) and 63 received rituximab+csDMARD (62% women; mean age 66 years; mean disease duration 17 years; 76% had RA/JIA and 10 % vasculitis). Controls (n=61) were 74% women and mean age 49 years. Compared to controls, rituximab patients had lower antibody levels for both spike proteins (p<0.001). Proportion (%) responders among patients receiving rituximab as monotherapy (40.2%) and rituximab+DMARDs (25.4%) was significantly lower than in controls (98.4%) (p<0.001, Chi2). Higher age, concomitant csDMARD at vaccination and shorter time from last rituximab treatment predicted impaired antibody response (multivariate logistic regression model) (Table 1). Longer time between the last rituximab course and vaccination was associated with better antibody response (Figure 1).

Table 1.

Predictors of good antibody response to two doses of COVID-19 vaccine defined as antibodies over the cut-off level for both spike antigens

Bp-valueOR95% CIAge at vaccination (years)-0.040.0090.960.93-0.99Sex (male/female)-9.550.2090.580.24-1.36csDMARD at vaccination (yes/no)-1.080.0260.340.13-0.88Prednisolone (mg/dag)-0.100.1030.900.80-1.02Rituximab dos (1000 mg vs 500 mg)-0.010.3700.990.99-1.00Time between the last rituximab and vaccination (months)0.200.0011.311.11-1.55Diagnosis at vaccination (systemic vasculitis vs others)-0.510.3150.600.21-1.64Figure 1.

The chance of good antibody response following two doses of COVID-19 vaccine in relation to time between the last rituximab course and vaccination.

Conclusion

Patients with IRD getting vaccinated with two doses of COVID19 vaccine during the treatment with rituximab have the ability to develop antibody response although the response is impaired. For each month passed after the last rituximab course, the chance of good antibody response increases with 30%. Younger patients receiving rituximab as monotherapy and vaccinated preferably several months after the last rituximab treatment have the highest chance of achieving a good antibody response.

Acknowledgements

Unrestricted research grants have been received from Roche and starting grants from The Swedish Rheumatism Association

Disclosure of Interests

Martina Frodlund: None declared, Katerina Chatzidionysiou Consultant of: consultancy fees from Eli Lilly, AbbVie and Pfizer., Anna Södergren: None declared, Eva Klingberg: None declared, Monika Hansson: None declared, Elisa Pin: None declared, Sophie Olsson: None declared, Anders Bengtsson: None declared, Lars Klareskog Grant/research support from: has eceived research grants from Pfizer, BMS, Affibody, Sonoma Biotherapeutics, Meliha C Kapetanovic Consultant of: have received consultancy fees from Abbvie, Pfizer and GSK, Grant/research support from: have received unrestricted research grants from Roche and Pfizer

Continuous Stabilization and Carbonization of a Lignin-Cellulose Precursor to Carbon Fiber

The demand for carbon fibers (CFs) based on renewable raw materials as the reinforcing fiber in composites for lightweight applications is growing. Lignin-cellulose precursor fibers (PFs) are a promising alternative, but so far, there is limited knowledge of how to continuously convert these PFs under industrial-like conditions into CFs. Continuous conversion is vital for the industrial production of CFs. In this work, we have compared the continuous conversion of lignin-cellulose PFs (50 wt % softwood kraft lignin and 50 wt % dissolving-grade kraft pulp) with batchwise conversion. The PFs were successfully stabilized and carbonized continuously over a total time of 1.0-1.5 h, comparable to the industrial production of CFs from polyacrylonitrile. CFs derived continuously at 1000 °C with a relative stretch of -10% (fiber contraction) had a conversion yield of 29 wt %, a diameter of 12-15 μm, a Young's modulus of 46-51 GPa, and a tensile strength of 710-920 MPa. In comparison, CFs obtained at 1000 °C via batchwise conversion (12-15 μm diameter) with a relative stretch of 0% and a conversion time of 7 h (due to the low heating and cooling rates) had a higher conversion yield of 34 wt %, a higher Young's modulus (63-67 GPa) but a similar tensile strength (800-920 MPa). This suggests that the Young's modulus can be improved by the optimization of the fiber tension, residence time, and temperature profile during continuous conversion, while a higher tensile strength can be achieved by reducing the fiber diameter as it minimizes the risk of critical defects.

Cognitive performance in systemic lupus erythematosus patients: a cross-sectional and longitudinal study

Background

Previous research has provided evidence for cognitive dysfunction as a common symptom of systemic lupus erythematosus (SLE). In light of this, the primary goal of this study was to investigate how cognitive impairment in this patient group develops over time. In addition, the present dataset contributes to delineating the specific abilities that are impaired in SLE patients as well as answering the question whether the disease affects the cognition of SLE patients with neuropsychiatric manifestations (NPSLE) and without (non-NPSLE) in distinct ways.

Methods

91 female participants (33 NPSLE, 29 non-NPSLE, 29 healthy controls (HC)) underwent standardized neurocognitive testing. A total of ten different cognitive abilities were assessed, among others executive function, memory, and attention. Some of the participants (30 NPSLE patients, 22 non-NPSLE, 13 HC) were tested twice (mean time between testing sessions: 50 months) to enable longitudinal tracking of cognitive abilities. Analyses of Variance (ANOVA) were conducted to determine whether cognitive performance differed cross-sectionally between the groups. Linear mixed effects models were fit to investigate performance differences between the groups over time.

Results

Cross-sectional analysis at follow-up demonstrated that the cognitive performance of both NPSLE and non-NPSLE was significantly lower than that of HC for the motor speed and the psychomotor speed domain. Additionally, NPSLE patients performed significantly weaker than HC in the complex attention domain. At the same time, the cross-sectional data did not yield any support for performance differences between NPSLE and non-NPSLE patients. Weak positive correlations between disease duration and psychomotor speed, motor speed and reaction time emerged. A temporal progression of cognitive dysfunction in SLE patients was not confirmed.

Conclusions

Cognitive performance is affected in both non-NPSLE and NPSLE patients. However, a linear decline in performance over time could not be verified. More in-depth longitudinal assessments of cognition in SLE patients are needed to establish how cognitive abilities in this patient population develop over time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41927-022-00253-3.

Realizing topologically ordered states on a quantum processor

[Figure: see text].

Time-Crystalline Eigenstate Order on a Quantum Processor

Quantum many-body systems display rich phase structure in their low-temperature equilibrium states¹. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases^2–8 that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC)^7,9–15. Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order^7,16,17. In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of superconducting qubits to experimentally observe an MBL-DTC and demonstrate its characteristic spatiotemporal response for generic initial states^7,9,10. Our work employs a time-reversal protocol to quantify the impact of external decoherence, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. Furthermore, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to studying non-equilibrium phases of matter on quantum processors.

A study establishes a scalable approach to engineer and characterize a many-body-localized discrete time crystal phase on a superconducting quantum processor.

Information scrambling in quantum circuits

[Figure: see text].

Reduced progression of carotid intima media thickness by pictorial presentation of subclinical atherosclerosis 3-year follow-up from VIPVIZA a randomized controlled trial

Background

Reduced progression of carotid intima media thickness (cIMT) and atherosclerotic plaque assessed by carotid ultrasound has been reported in pharmacological intervention studies. We have previously provide evidence for improved primary prevention of cardiovascular diseases by pictorial presentation of subclinical atherosclerosis severity based on reduction in traditional risk scores in 1-year follow-up.

Purpose

We aimed to investigate if pictorial presentation of subclinical atherosclerosis severity affected cIMT and plaque progression over a 3-year follow-up period in comparison with a routine primary prevention program.

Methods

Visualization of asymptomatic atherosclerotic disease for optimum cardiovascular prevention (VIPVIZA) study is a population-based, randomized controlled trial with blinded evaluators (PROBE design). Participants aged 40, 50 and 60 years were enrolled from a prevention program within the routine primary care. Carotid ultrasound examinations were made at baseline and at 3-year follow-up (n: 3154). The ultrasound examinations included standardized measurements of cIMT in the far wall of common carotid artery at predefined angles due to Meijer's arc. Used angles was 240 degrees for left-mean-cIMT and 120 degrees for right-mean-cIMT. Detection of plaque was based on Mannheim consensus and plaque prevalence was evaluated as absent, unilateral or bilateral plaques. Total plaque area (TPA) was a sum of plaque areas and measured off-line form the longitudinal 2D B-mode images. At baseline, the intervention group (n: 1575) and their primary care physicians received a pictorial presentation describing the severity of subclinical atherosclerosis with graphs and colored figures based on measured cIMT and plaque prevalence (Figure 1). The control group with respective physician (n: 1579) did not receive any information about ultrasound results. The bilateral, left and right mean cIMT, plaque prevalence and TPA at 3-year follow-up were compared between groups. Analysis was performed by analysis of covariance and ordinal proportional odds models. Bonferroni correction was applied to account for multiple comparisons, each individual test was performed using α = 0.01.

Results

Reduced cIMT progression in the intervention group was found in left-mean-cIMT with an estimated group difference of −0.011 mm (p=0.001). Estimated group difference of right- and bilateral-mean-cIMT were both −0.005 mm (p=0.223 and 0.036, respectively) (Figure 2). No significant difference between groups was found for plaque prevalence or TPA.

Conclusion

Intervention by pictorial presentation of subclinical atherosclerotic severity reduced the progression of cIMT in comparison with a traditional cardiovascular preventive program only. This was largely driven by changes in the left carotid artery. Long-term follow-up will be required to elucidate if the intervention will have a protective effect on future risk of cardiovascular events.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Heart Foundation of Northern Sweden, Västerbotten County Council. Figure 1Figure 2

Pictorial information about subclinical atherosclerosis reduces the CVD risk: Results from the VIPVIZA RCT

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Region Västerbotten and the Swedish Research Council

Background

The VIPVIZA trial has previously shown beneficial effects on cardiovascular disease (CVD) risk scores 1 year after sending pictorial information of carotid ultrasound imaging (Picture 1) to individuals and their physicians

Purpose

To investigate whether the beneficial effects on CVD-risk observed at 1-year were sustained over three years 

Methods

VIPVIZA is a pragmatic prospective open-label randomized controlled trial with blinded evaluators performed within a CVD prevention programme integrated in the regular primary health care in Västerbotten County, Sweden. Individuals aged 40, 50 or 60 years old with one CVD risk factor were enrolled and randomised 1:1 to intervention (n = 1749, pictorial information about subclinical atherosclerosis provided to participants and physicians, Picture 1) or control group(n = 1783, no information to participants or physicians). Intervention participants also recieved a follow-up phone call and the corresponding physicians written guideline-based information about the clinical significance of carotid ultrasound results. Participants were examined at baseline (2013-2016), after one and at three years

Results

A significant beneficial effect on cardiovascular risk was observed at the 3-year follow-up; Framingham Risk Score (FRS) was 13.38 for the intervention group and 14.08 for the control group(p = 0.047) and SCORE was 1.69 vs. 1.82(p = 0.022) respectively. The 3-year results adjusted for sex and educational level showed significant differences between the intervention and control group in FRS, SCORE, P-Total-Cholesterol, P-LDL-Cholesterol and waist circumference in favour of the intervention group. Analysis by sex showed difference in differences(DID) in FRS for men -1.19(95% CI -2.01 to -0.37) and -0.50(95% CI -0.93 to -0.07) for women and in SCORE for men -0.20(95% CI -0.33 to -0.06) and -0.08 (95% CI -0.13 to -0.04) for women, between the two groups over 3 years. Similarly, there were significant differences in DID in all educational groups. Further stratification by baseline FRS and SCORE risk category, showed a beneficial pattern of the intervention in all risk groups, however the DID at the 3-year follow-up was statistically significant only in the intermediate risk group for both FRS -1.34(95% CI -2.13 to -0.56) and SCORE -0.19(95% CI -0.32 to -0.05)

Conclusions

This study provides evidence of sustained effects over three years of pictorial information of subclinical carotid atherosclerosis on the reduction of cardiovascular risk regardless of sex and educational level. Importantly, a statistically significant intervention effect was seen in the intermediate risk group, where the majority of CVD events occur. Visualization of subclinical atherosclerosis may be one way to approach individuals at intermediate risk of CVD, a group where sufficient prevention is often overlooked. However, further studies are needed to investigate the intervention effect on hard end points as CVD-events and death.

Abstract Figure. Picture 1

Multi-level quantum noise spectroscopy

System noise identification is crucial to the engineering of robust quantum systems. Although existing quantum noise spectroscopy (QNS) protocols measure an aggregate amount of noise affecting a quantum system, they generally cannot distinguish between the underlying processes that contribute to it. Here, we propose and experimentally validate a spin-locking-based QNS protocol that exploits the multi-level energy structure of a superconducting qubit to achieve two notable advances. First, our protocol extends the spectral range of weakly anharmonic qubit spectrometers beyond the present limitations set by their lack of strong anharmonicity. Second, the additional information gained from probing the higher-excited levels enables us to identify and distinguish contributions from different underlying noise mechanisms.

Observation of Broadband Entanglement in Microwave Radiation from a Single Time-Varying Boundary Condition

Entangled pairs of microwave photons are commonly produced in the narrow frequency band of a resonator, which represents a modified vacuum density of states. We generate and investigate the entanglement of a stream of photon pairs, generated in a semi-infinite broadband transmission line, terminated by a superconducting quantum interference device (SQUID). A weak pump signal modulates the SQUID inductance, resulting in a single time-varying boundary condition, and we detect all four quadratures of the microwave radiation emitted at two different frequencies separated by 0.7 GHz. Power calibration is done in situ, and we find positive logarithmic negativity and two-mode squeezing below the vacuum in the observed radiation, indicating entanglement.

White matter lesions and brain atrophy in systemic lupus erythematosus patients: correlation to cognitive dysfunction in a cohort of systemic lupus erythematosus patients using different definition models for neuropsychiatric systemic lupus erythematosus

Aim

The aim of this study was to evaluate the extent of white matter lesions, atrophy of the hippocampus and corpus callosum, and their correlation with cognitive dysfunction (CD), in patients diagnosed with systemic lupus erythematosus (SLE).

Methods

Seventy SLE patients and 25 healthy individuals (HIs) were included in the study. To evaluate the different SLE and neuropsychiatric SLE (NPSLE) definition schemes, patients were grouped both according to the American College of Rheumatology (ACR) definition, as well as the more stringent ACR-Systemic Lupus International Collaborating Clinics definition. Patients and HIs underwent a 3 Tesla brain MRI and a standardized neuropsychological test. MRI data were evaluated for number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum. Differences between groups and subgroups were evaluated for significance. Number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum were correlated to cognitive dysfunction.

Results

The total volume of white matter lesions was significantly larger in SLE patients compared to HIs ( p = 0.004). However, no significant differences were seen between the different SLE subgroups. Atrophy of the bilateral hippocampus was significantly more pronounced in patients with NPSLE compared to those with non-NPSLE (right: p = 0.010; left p = 0.023). Significant negative correlations between cognitive test scores on verbal memory and number and volume of white matter lesions were present.

Conclusion

SLE patients have a significantly larger volume of white matter lesions on MRI compared to HIs and the degree of white matter lesion volume correlates to cognitive dysfunction, specifically to verbal memory. No significant differences in the number or volume of white matter lesions were identified between subgroups of SLE patients regardless of the definition model used.

Blood salvage with a continuous autotransfusion system compared with a haemofiltration system

Background: Red blood cells may be destroyed by autotransfusion processing during intraoperative salvage. The aim of the present study was to evaluate the blood component recovery rate of techniques built on either continuous centrifugation and washing, or haemofiltration (HF).

Methods: Two different methods used in blood salvage - red cell salvage with continuous processing with centrifugation and saline washing (Continuous Auto Transfusion System, CATS) and whole blood recirculation through a 30000-Da filter, i.e., HF - were compared in a randomized laboratory study using donor whole blood activated by cobra venom factor. The recovery of red blood cells, haemoglobin, free haemoglobin, leucocytes, platelets, albumin, total protein and potassium was measured.

Results: The recovery of red cells was 86% with CATS and 76% with HF. HF had a significantly higher recovery of leucocytes (CATS 20%, HF 63%), platelets (CATS 4%, HF 37%), albumin (CATS 0.2%, HF 70%), total protein (CATS 1.3%, HF 71%) and potassium (CATS 2%, HF 17%). Less than 1% haemolysis was obtained in processed blood from both groups.

Conclusion: Both methods caused little destruction of the red blood cells during processing. There was a larger reinfusion of leucocytes, platelets, albumin, total protein and extracellular potassium when HF was used compared with the ‘CATS’ method.

Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator

We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing.

Decreased muscle concentrations of ATP and PCR in the quadriceps muscle of fibromyalgia patients--a 31P-MRS study

BACKGROUND AND METHODS

Fibromyalgia (FMS) has a prevalence of approximately 2% in the population. Central alterations have been described in FMS, but there is not consensus with respect to the role of peripheral factors for the maintenance of FMS. 31P magnetic resonance spectroscopy (31P-MRS) has been used to investigate the metabolism of phosphagens in muscles of FMS patients, but the results in the literature are not in consensus. The aim was to investigate the quantitative content of phosphagens and pH in resting quadriceps muscle of patients with FMS (n = 19) and in healthy controls (CONTROLS; n = 14) using (31) P-MRS. It was also investigated whether the concentrations of these substances correlated with measures of pain and/or physical capacity.

RESULTS

Significantly lower concentrations of adenosine triphosphate (ATP) and phosphocreatinine (PCr; 28-29% lower) were found in FMS. No significant group differences existed with respect to inorganic phosphate (Pi), Pi/PCr and pH. The quadriceps muscle fat content was significantly higher in FMS than in CONTROLS [FMS: 9.0 ± 0.5% vs.

CONTROLS

6.6 ± 0.6%; (mean ± standard error); P = 0.005]. FMS had significantly lower hand and leg capacity according to specific physical test, but there were no group differences in body mass index, subjective activity level and in aerobic fitness. In FMS, the specific physical capacity in the leg and the hand correlated positively with the concentrations of ATP and PCr; no significant correlations were found with pain intensities.

CONCLUSIONS

Alterations in intramuscular ATP, PCr and fat content in FMS probably reflect a combination of inactivity related to pain and dysfunction of muscle mitochondria.

Alternative pathway activation of complement in laparoscopic and open rectal surgery

The study was designed to investigate whether complement is activated in patients subject to rectal surgery and whether the choice of surgical technique (open or laparoscopic) has any impact on the activation of complement. Our hypothesis is that laparoscopic surgery leads to a lower-level activation of complement than open surgery. Patients (n = 24) subject to rectal surgery owing to rectal cancer were included. The study was prospective and randomized. The patients were randomized to either laparoscopic surgery (n = 12) or open surgery (n = 12). Blood samples for determination of complement activation (C4d, Bb, C3bc and the terminal C5b-9 complex TCC) were drawn before start of surgery (T0) and at the following time-points after start of surgery: 180 min (T1), 360 min (T2), 24 h (T3) and 3-5 days (T4). A significant increase in the alternative pathway activation product Bb and in the terminal pathway activation product TCC was seen over time in both groups (P < 0.001). Bb peaked early (T1) and returned to baseline levels post-operatively, whereas TCC increased steadily with maximum values in the late post-operative period. The plasma concentrations of C4d and C3bc decreased significantly in both groups at T1 and T2 and returned to baseline levels at T4. There was no significant difference between the groups. Rectal surgery causes activation of the complement system. Complement is activated through the alternative pathway. Results mostly showed no significant differences between laparoscopic and open rectal surgery apart from lower levels of factor Bb in the former group in the perioperative period.

Inflammatory response in patients undergoing colorectal cancer surgery: the effect of two different anesthetic techniques

BACKGROUND

Anesthesia during surgery often induces an inflammatory response. The aim of this study was to establish and compare differences in inflammatory response among colorectal cancer surgery patients receiving either total intravenous anesthesia (TIVA) with propofol and remifentanil or inhalational anesthesia (INHAL) with sevoflurane and fentanyl.

METHODS

After randomization, we included fifty consecutive patients undergoing colorectal cancer surgery in our study. TIVA patients received total intravenous anesthesia with propofol and remifentanil, while INHAL patients received inhalation anesthesia with sevoflurane in O2/air and fentanyl. Plasma concentrations of IL-8, IL-17, MPO, ICAM-1, V-CAM and L-selectin were quantified. Blood loss, body temperature and blood glucose levels were measured in patients both before and after surgery.

RESULTS

In both groups, levels of IL-8, MPO, ICAM-1 and L-selectin decreased 60 min after the start of surgery (P<0.05, P<0.01, respectively) and 30 min post-surgery (P<0.05 for both groups). In the INHAL group, V-CAM levels were significantly lower 60 min after the start of surgery (P<0.01) and 30 min post-surgery (P<0.05). At 24 h post-surgery, V-CAM levels were significantly higher in both groups (P<0.01), while IL-17 levels significantly increased only in the INHAL group (P<0.05). Higher blood glucose levels were also observed in the INHAL group compared to that in the TIVA group (P<0.01).

CONCLUSION

TIVA with propofol and remifentanil and INHAL with sevoflurane and fentanyl induced similar inflammatory responses during colorectal cancer surgery. We found that IL-17 cytokine levels were higher in patients anesthetized with sevoflurane and fentanyl.

Transfusion of intra-operative autologous whole blood: influence on complement activation and interleukin formation

BACKGROUND AND OBJECTIVES

Transfusion of autologous whole blood is one available method to reduce the need for allogenic blood transfusion. The objective of this study was to investigate the safety of transfusion of intra-operative autologous whole blood by monitoring plasma concentration of laboratory variables and adverse events after transfusion with the Sangvia(®) system.

MATERIALS AND METHODS

The clinical trial was designed as an open, prospective, multi-centre study, and a total of 20 patients undergoing primary hip arthroplasty were included. Systemic blood samples were taken and analysed preoperatively, at transfusion start and end and at 3, 6, 24 and 48 h after the transfusion.

RESULTS

Elevated values of complement activation and pro-inflammatory cytokines were seen in the intra-operatively collected blood but the impact on systemic levels were limited with low peak levels, systemic elevations before transfusion and normalization during the study period. Elevated levels of free haemoglobin and potassium were also detected in the intra-operatively collected blood, but systemic values were within reference values after the transfusion. No clinically relevant adverse event occurred during the study.

CONCLUSION

Inflammatory mediators and plasma haemoglobin were increased in intra-operatively salvaged and filtered blood compared to circulatory levels. Intra-operative retransfusion of autologous whole blood caused a transient systemic increase that normalized in the early postoperative period. There were no significant adverse events reported in the study. These data suggest that the Sangvia(®) system can be used for intra-operative collection and retransfusion of salvaged blood.

An unnecessary case of paraffin oil pneumonia

A 64-year-old woman died after 12 years of progressive pulmonary disease which was initially diagnosed as sarcoidosis but later correctly identified as mineral oil pneumonia due to insufflation of paraffin instilled as nasal drops. In view of the potential damaging effect of liquid paraffin on the lungs, the current indications for its use must be strongly questioned.

Complement split products and proinflammatory cytokines in intraoperatively salvaged unwashed blood during hip replacement: comparison between heparin-coated and non-heparin-coated autotransfusion systems

BACKGROUND AND OBJECTIVES

The aim of the present study was to investigate the quality of shed blood collected in a new intraoperative autotransfusion system (Sangvia, AstraTech, Sweden) and to study whether heparin-coated surfaces in the device reduce the production of inflammatory mediators.

MATERIAL AND METHODS

The study was randomized and prospective. Twelve total hip arthroplasty patients whose blood was collected with a device having a heparin-coated surface and 12 patients whose blood was collected with a device having a non-heparin-coated surface were included. Venous blood was drawn from the patients preoperatively. Intraoperatively 200 ml salvaged blood was collected and samples were also withdrawn; samples were obtained from the blood bag.

RESULTS

Compared to venous blood, elevated concentrations of interleukin 6 (IL-6), IL-8, C3a and polymorphonuclear elastase were found in collected blood. No significant differences in inflammatory mediators were found between the heparin-coated and the non-heparin-coated groups. The median haemoglobin concentration in the salvaged blood was 74 g/l in both groups. Plasma haemoglobin and potassium concentrations were also elevated. There were no significant differences between the groups.

CONCLUSION

The present study indicates that the blood salvaged intraoperatively contains elevated levels of complement split product and proinflammatory cytokines and that heparin-coated surfaces of the salvage device do not significantly influence the formation of inflammatory mediators.

Plasma concentration of procalcitonin and systemic inflammatory response syndrome after colorectal surgery

BACKGROUND

To study whether plasma concentrations of procalcitonin (PCT), interleukin-6 (IL-6), complement 3a (C3a), C-reactive protein and white blood cell count (WBC) correlate with the presence of systemic inflammatory response syndrome (SIRS) during the early post-operative period after major colorectal surgery.

METHODS

Prospective, observational study during the first 24 h post-operatively. The setting for the study was the operating theatre and the recovery unit at the university hospital. Fifty consecutive patients, operated on electively with major resection of the large bowel or rectum. PCT levels increased significantly to the maximum level 18 h postoperatively. PCT levels were significantly higher in the SIRS group in comparison to the non-SIRS group of patients 6 and 12 h after surgery (P < 0.05). The IL-6 levels were increased directly after the surgery and then decreased gradually in both study groups. Twenty-four hours after the surgery, C3a levels decreased and then returned to normal levels. Twenty-four hours post-operatively, patients with SIRS had a higher plasma concentration of C3a compared with patients without SIRS (P < 0.05). CRP and WBC increased during the study period in both groups (P < 0.05).

CONCLUSIONS

During the early post-operative period after uncomplicated major abdominal surgery, SIRS was reflected by the increase in plasma PCT and C3a concentrations. IL-6, CRP and WBC increased to the same extend in both the SIRS and the non-SIRS group of patients.

IL-6 and IL-8 response to erythropoietin therapy in radical hysterectomy

BACKGROUND

The use of recombinant human erythropoietin (rHuEPO) improves autologous blood donation before elective surgery. However, there are other studies indicating that rHuEPO may suppress postoperative endogenous production of erythropoietin and stimulate inflammatory mediator release. Weekly donations generate only a moderate increase in endogenous erythropoietin production. We scheduled patients with cancer to predeposit three units of blood in 2 weeks, with or without rHuEPO therapy. The aim was to determine whether rHuEPO therapy and/or an aggressive donation schedule alter perioperative erythropoietin concentrations and whether rHuEPO therapy leads to the release of the pro-inflammatory cytokines IL-6 and IL-8.

METHODS

Thirty women scheduled for radical hysterectomy and pelvic lymphadenectomy were randomly assigned to either a control group with no rHuEPO therapy or to receive rHuEPO. Three units of whole blood were collected from each patient before the operation. Concentrations of haemoglobin, erythropoietin (s-EPO) and cytokines (IL-6 and IL-8) were repeatedly analyzed before and after the operation.

RESULTS

During the preoperative donation period, median s-EPO levels in the control group increased from 7 to 14 IU l(-1). There was a great increase in s-EPO concentrations 1 h postoperatively in the rHuEPO group compared with the control group (P < 0.001). IL-6 and IL-8 were not significantly changed after intravenous administration of rHuEPO.

CONCLUSION

The use of rHuEPO therapy to optimise autologous blood donation does not influence IL-6 and IL-8 release. 1 h postoperatively rHuEPO therapy resulted in elevated s-EPO concentrations. There was, however, no difference in s-EPO between the groups from day 1 postoperatively and until the end of the study.

Complement activation in prestorage leucocyte-filtered plasma

Complement activation and generation of pro-inflammatory cytokines occur during storage of blood components. Prestorage leucocyte filtration of platelet concentrates and red cells diminishes the accumulation of leucocyte-derived cytokines during storage, however, transfusion reactions are not eliminated. We investigated inflammatory mediator release during storage of plasma and whole blood and the effect of prestorage leucocyte filtration of plasma. Twenty-four blood units were collected from healthy blood donors and stored for 35 days. Eight units were stored as whole blood, eight units as plasma and eight units as prestorage filtered plasma. Samples were collected weekly for analyses of potassium, leucocytes, free plasma haemoglobin, complement activation (C3a and SC5b-9) and pro-inflammatory cytokines [interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha]. Elevated levels of C3a and SC5b-9 were registered in filtered plasma, from the beginning of storage. C3a levels increased during storage. There was a higher rate of change during storage in C3a (P < 0.01) and SC5b-9 (P < 0.05) in plasma compared with filtered plasma. Interleukin (IL)-8 is released in whole blood. The cytokine levels generated in plasma and filtered plasma were low. Complement activation is present in whole blood, plasma and filtered plasma during storage. Prestorage filtration of plasma activates the complement cascade but does not influence cytokine generation.

Influence of cold ischemia time on complement activation, neopterin, and cytokine release in liver transplantation

OBJECTIVES

The aim of this study was to determine whether a cold ischemia time (CIT) of >12 hours influences the activation of complement as well as the plasma concentrations of neopterin, interleukin (IL)-6, or IL-8 in orthotopic liver transplantation (OLT).

PATIENTS AND METHODS

Eighteen consecutive patients undergoing OLT using a veno-venous bypass technique were divided into 2 groups: duration of CIT >12 hours (group 1; n = 11), and CIT <12 hours (group 2; n = 7). Blood samples were drawn preoperatively, 1 minute before, and 120 minutes after reperfusion.

RESULTS

Preoperatively, complement split products, neopterin, IL-6, and IL-8 levels did not differ between the groups. At 120 minutes after reperfusion, the concentrations of C3a, SC5b-9, neopterin, IL-6, and IL-8 were significantly increased in both groups compared with the preoperative values or the levels determined 1 minute before reperfusion (P < .05). Patients in group 1 showed significantly higher IL-8 levels at 120 minutes after reperfusion (P < .05).

CONCLUSION

Complement is activated and pro-inflammatory cytokines released after reperfusion in OLT using a veno-venous bypass technique, but only IL-8 plasma levels were influenced by the duration of CIT. Therefore, alterations following prolonged CIT seem to not be complement-mediated.

Nicotinamide does not influence cytokines or exhaled NO in human experimental endotoxaemia

This study examined the hypothesis that nicotinamide could attenuate endotoxin-induced inflammatory responses in humans as indicated by levels of cytokines and nitric oxide. Ten healthy male volunteers participated in a randomised, double-blind, cross-over design with regard to the effects of nicotinamide. The volunteers received orally 4 g nicotinamide or placebo at 14 h and at 2 h preceding the experiment (total dose of 8 g). Endotoxin (E. coli, 2 ng/kg), was administered intravenously. Blood samples and haemodynamic data were collected prior to and up to 6 h after the endotoxin infusion. Orally exhaled NO was measured hourly. Following endotoxin, body temperature increased from baseline 36.3 +/- 0.09 degrees C to a maximum of 38.0 +/- 0.1 degrees C for all (mean +/- SEM, P < 0.001) and heart rate increased from 59 +/- 1.9 to 87.0 +/- 2.6 beats/min after 3 h (mean +/- SEM, P < 0.001). Endotoxin challenge also markedly elevated the TNF-alpha, IL-6, IL-8 and IL-10 concentrations (P < 0.001 versus baseline for all) during the study period. Orally exhaled NO also increased (P < 0.01) compared to baseline. Nicotinamide treatment did not influence the patterns of cytokine and NO response to endotoxin. In conclusion, there was no effect on the inflammatory parameters by oral nicotinamide at a dose of 8 g, limiting the potential use of this agent for anti-inflammatory purpose in man.

Levels of soluble CD30 in cord blood and peripheral blood during childhood are not correlated with the development of atopic disease or a family history of atopy

BACKGROUND

The CD30 molecule has been linked to Th2 responses. Furthermore, elevated levels of the soluble form of CD30 (sCD30) in blood as well as of the expression of CD30 on the plasma membrane of T cells are associated with atopic disease.

OBJECTIVE

To assess the potential usefulness of sCD30 levels as a prognostic indicator of and/or diagnostic marker for the development of atopic disease in children.

METHODS

sCD30 levels in cord blood and peripheral blood from 36 2-year-old (10 atopic and 26 non-atopic) and 74 7-year-old (35 atopic and 39 non-atopic) children were determined employing an ELISA procedure. Atopy was diagnosed on the basis of clinical evaluation in combination with a positive skin prick test.

RESULTS

No significant correlation between sCD30 levels in cord blood and the development of atopic disease at 2 or 7 years of age was observed. At 7 years of age, the circulating sCD30 levels in children with atopic disease (median 41 U/mL, range 6-503 U/mL) did not differ from the corresponding values for non-atopic subjects (median 41 U/mL, range 8-402 U/mL). The same was true for children at 2 years of age. Furthermore, the sCD30 levels of children who had developed atopic eczema/dermatitis syndrome by the age of 7 years (median 49 U/mL, range 14-503 U/mL) were not significantly elevated in comparison with those of the non-atopic children. Finally, neither sCD30 levels in cord blood nor peripheral blood at 2 or 7 years of age could be linked to a family history of atopy.

CONCLUSION

These findings indicate that the sCD30 concentration in cord blood is not a reliable prognostic indicator of, nor a useful diagnostic marker for, atopic disease in children up to 7 years of age. If such correlations do exist, they might be masked by age-dependent variations in the circulating levels of sCD30, which may reflect individual differences in the maturation of children's immunological responses.

Complement activation, endothelin-1 and neuropeptide Y in relation to the cardiovascular response to endotoxin-induced systemic inflammation in healthy volunteers

BACKGROUND

Endotoxin is a major stimulus for triggering the host response in septicaemia. The pathophysiology of sepsis involves activation of the vascular endothelium and leukocytes, resulting in the release of various mediators, e.g. cytokines, nitric oxide (NO), endothelin (ET-1) and complement factors. We evaluated the blood levels of complement activation, ET-1 and neuropeptide Y (NPY) in parallel with the haemodynamic and oxygen transport response during human experimental endotoxemia.

METHODS

Eleven healthy men had venous, arterial and pulmonary arterial catheters placed for continuous haemodynamic measuring. After 30 min rest endotoxin (E. Coli 4 ng kg(-1), Lot G1) was intravenously administered. Blood samples from pulmonary and arterial catheters were collected hourly over 4 h.

RESULTS

Body temperature augmented significantly from baseline values (36.7 +/- 0.7 degrees C, mean +/- SEM) with a maximum after 3.5 h (39.1 +/- 0.3 degrees C, P < 0.001). Cardiac output increased by 100%, systemic vascular resistance decreased by 50%, the oxygen consumption and the tissue oxygen transport increased. Activation of the complement system was indicated by an increase in SC5b-9. Endothelin-1-like immunoreactivity (ET-1-LI) increased over time in arterial blood. NPY-like immunoreactivity (NPY-LI) did not change over time.

CONCLUSION

A dose of endotoxin associated with reproducible systemic vasodilation and fever in healthy subjects causes complement activation and increased systemic levels of ET-1-LI, illustrating that the model is a useful tool for inducing moderate systemic inflammation where several mediator systems are activated.

Muscle metabolism in fibromyalgia studied by P-31 magnetic resonance spectroscopy during aerobic and anaerobic exercise

OBJECTIVE

To investigate mechanisms underlying the reduced work capacity of fibromyalgia (FM) patients were compared to healthy controls at specified workloads, using P-31 magnetic resonance spectroscopy (MRS).

METHODS

The forearm flexor muscle group was examined with MRS at rest, at sub maximal and at maximal controlled dynamic work as well as at maximal isometric contraction. Aerobic fitness was determined by bicycle ergonometry.

RESULTS

Metabolite concentrations and muscle pH were similar for patients and controls at lower workloads. At maximal dynamic and static contractions the concentration of inorganic phosphate was lower and at static contractions the pH decrease was smaller in patients. The performed work by patients was only 50% compared to controls and the patients experienced more pain. Maximal oxygen uptake was lower in the fibromyalgia group. Expired gas-analysis in this group showed ventilatory equivalents at similar relative levels of maximal work capacity.

CONCLUSION

Fibromyalgia patients seem to utilise less of the energy rich phosphorous metabolites at maximal work despite pH reduction. They seemed to be less aerobic fitted and reached the anaerobic threshold earlier than the controls.

Recombinant human erythropoietin in preoperative autologous blood donation did not influence the haemoglobin recovery after surgery

BACKGROUND

Recombinant human erythropoietin in combination with preoperative autologous blood donation is an established regime for avoiding allogenic blood transfusions. The aim of the study was to determine endogenous erythropoietin production and haemoglobin recovery after preoperative autologous blood donation and surgery, with or without recombinant human erythropoietin treatment.

METHODS

Thirty-eight patients having total hip joint replacement surgery were randomised to receive either autologous blood transfusion (control group) or autologous transfusion plus preoperative recombinant human erythropoietin treatment (EPO group). Haemoglobin, haematocrit, erythropoietin and reticulocyte concentrations were repeatedly analysed, before, during, and after surgery.

RESULTS

No significant differences were found between the groups regarding haemoglobin, haematocrit, and erythropoietin, but the reticulocyte count increased significantly more in the EPO group. There was no difference in the requirement for allogeneic blood transfusions between the groups. The baseline haemoglobin was >13 g dL-1 in all but four patients.

CONCLUSIONS

In patients with normal preoperative haemoglobin levels, recombinant human erythropoietin treatment did not improve haemoglobin levels, or reduce the need for allogenic blood transfusion. There were no differences in serum erythropoietin concentrations between the groups. We question whether recombinant human erythropoietin treatment facilitates preoperative autologous blood donation in patients with normal haemoglobin levels.

Inflammatory mediators in autotransfusion drain blood after knee arthroplasty, with and without leucocyte reduction

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate whether leucocyte-reducing filters influenced complement activation and the formation of pro-inflammatory cytokines in autotransfusion drain blood after knee arthroplasty.

MATERIALS AND METHODS

Twenty-three patients undergoing knee arthroplasty were divided into two groups. All patients were given salvage blood postoperatively. In Group A, a leucocyte filter was connected between the wound and the drain blood container. In Group B the drain blood was not leucocyte filtered. Complement split products and cytokines were analysed in circulating blood and in drain blood, together with blood-cellular differential counts.

RESULTS

Drain blood showed activation vs. venous blood, with elevated concentrations of C3a, SC5b-9, interleukin (IL)-6, IL-8, polymorphonuclear (PMN) elastase and tumour necrosis factor-alpha (TNF-alpha) (P<0.05 to P<0.001). The leucocyte filter reduced TNF-alpha (P<0.01), but triggered complement activation (P<0.05). Room-temperature incubation increased the concentration of IL-8 (P<0.01), which was seen in both venous and drain blood. The leucocyte filter prevented formation of IL-8 (P<0.01). In drain blood at 24 h the inflammatory reactions accelerated (P<0.05-0.001), although the filter reduced the leucocyte counts and TNF-alpha concentrations.

CONCLUSIONS

The leucocyte filter reduced IL-8 and TNF-alpha in drain blood, but at the same time triggered complement activation. Incubation affected the inflammatory spectrum of both drain blood and control venous blood, and the filtering reduced this activation.

Increased serum erythropoietin concentration after allogeneic compared with autologous blood transfusion

Serum erythropoietin (sEPO) level is known to increase as hemoglobin (Hb) concentration decreases during and after preoperative autologous blood donation (PAD). The endogenous erythropoietin (EPO) production after allogeneic blood transfusion has not to our knowledge, been studied. The aim of the present study was to determine whether there is, after surgery, any change in sEPO concentration after allogeneic blood transfusion, and whether there is any difference in EPO response after autologous or allogeneic blood transfusion. Thirty-one patients approaching total hip-joint replacement surgery, were randomized to receive either allogeneic red blood cells (n = 15) or predeposited autologous whole blood transfusion (n = 16). The relationship between Hb, sEPO, and reticulocytes in the recipients were repeatedly analyzed before, during and after surgery. The Hb followed an expected pattern, with a decreased concentration after PAD in the autologous group, then in both groups after surgery. The sEPO concentration was significantly higher in the allogeneic than in the autologous group on day one and day 4-5 postoperatively. The reticulocyte level, on the contrary, was higher in the autologous patients before, one hour after, and one day after surgery. The study showed a greater increase in sEPO concentration after allogeneic blood transfusion than after autologous blood transfusion. There may be an inverse relationship between sEPO and the reticulocyte level.

Malignancies during follow-up in an epidemiologically defined systemic lupus erythematosus inception cohort in southern Sweden

The objective of this study was to identify all malignancies in an inception cohort of SLE patients in southern Sweden and compare with the observed frequencies and spectrum of malignancies in the general population. All adult incidence cases of SLE in a defined population during the period 1981-1996 were retrieved from a prospective database and the cases were followed to endpoint or through 1998. The SLE cohort registry was aggregated with the National Cancer Registry to identify all malignancies by date, type and outcome. Standardized morbidity rates (SMR) were calculated based on the sex- and age-matched general population of the region. Sixteen malignancies occurred in 13 patients out of a total of 116 SLE patients observed for 1086 patient-years. The SMR for all cancers detected was 2.24 (confidence interval 0.6-5.7) for males and 1.02 (confidence interval 0.4-2.1) for females and thus indicative of no general increase in malignancies. However, the SMR for non-Hodgkin lymphoma was 11.63 (confidence interval 1.4-42.0), for pulmonary cancer 5.55 (confidence interval 0.7-20.1) and prostatic cancer 6.41 (confidence interval 1.3-18.7) all significantly increased. The increase in prostatic carcinoma disappeared when only cases occurring after a latency period of 3y after SLE diagnosis were included. In this comprehensive inception cohort of SLE no increase in relative risk of malignancy overall was found, but the frequencies of non-Hodgkin lymphoma and pulmonary cancer were increased, possibly also the frequency of prostatic carcinoma.