Thyroidectomy for Euthyroid Patients with Hashimoto Disease and Persistent Symptoms: An Observational, Postrandomization Study.

Background: Despite adequate hormone substitution in Hashimoto disease, some patients may have persistent symptoms with a possible autoimmune pathophysiology. A recent randomized trial (RCT) using patient-reported outcome measures as the primary endpoint showed benefit in total thyroidectomy, but at a cost of high complication rates. Objective: To verify results from the RCT in an observational study including a wider range of patients and explore means of predicting who may benefit from such surgery. Design: A total of 154 patients with Hashimoto disease, euthyroid with or without thyroid hormone substitution, and persistent Hashimoto-related symptoms were subjected to total thyroidectomy and followed for 18 months after surgery. The primary outcome was the General Health (GH) dimensional score in the Short Form-36 Health Survey (SF-36). Results: Eighteen months after surgery, a clinically significant improvement in GH was seen, similar to the findings in the previous RCT. Anti-TPO antibody titers were markedly reduced after surgery, but preoperative titers or other preoperative parameters could not predict the outcome of surgery. Three (1.9%) of 154 patients experienced permanent unilateral recurrent nerve palsy and six (3.9%) experienced hypoparathyroidism after surgery. Conclusions: Thyroidectomy had a beneficial symptom-reducing effect in euthyroid patients with Hashimoto disease and persistent symptoms. The pathophysiology of residual symptoms remains unclear, and surgical complication rates are high. If thyroidectomy is considered as a treatment option, it should be performed in dedicated centers with experienced endocrine surgeons and as part of further studies on persistent symptoms. This trial is registered with NCT-02319538.

The HLA region in ANCA-associated vasculitis: characterisation of genetic associations in a Scandinavian patient population.

OBJECTIVE: The antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are inflammatory disorders with ANCA autoantibodies recognising either proteinase 3 (PR3-AAV) or myeloperoxidase (MPO-AAV). PR3-AAV and MPO-AAV have been associated with distinct loci in the human leucocyte antigen (HLA) region. While the association between MPO-AAV and HLA has been well characterised in East Asian populations where MPO-AAV is more common, studies in populations of European descent are limited. The aim of this study was to thoroughly characterise associations to the HLA region in Scandinavian patients with PR3-AAV as well as MPO-AAV. METHODS: Genotypes of single-nucleotide polymorphisms (SNPs) located in the HLA region were extracted from a targeted exome-sequencing dataset comprising Scandinavian AAV cases and controls. Classical HLA alleles were called using xHLA. After quality control, association analyses were performed of a joint SNP/classical HLA allele dataset for cases with PR3-AAV (n=411) and MPO-AAV (n=162) versus controls (n=1595). Disease-associated genetic variants were analysed for association with organ involvement, age at diagnosis and relapse, respectively. RESULTS: PR3-AAV was significantly associated with both HLA-DPB1*04:01 and rs1042335 at the HLA-DPB1 locus, also after stepwise conditional analysis. MPO-AAV was significantly associated with HLA-DRB1*04:04. Neither carriage of HLA-DPB1*04:01 alleles in PR3-AAV nor of HLA-DRB1*04:04 alleles in MPO-AAV were associated with organ involvement, age at diagnosis or relapse. CONCLUSIONS: The association to the HLA region was distinct in Scandinavian cases with MPO-AAV compared with cases of East Asian descent. In PR3-AAV, the two separate signals of association to the HLD-DPB1 region mediate potentially different functional effects.

Less, but not gone-gluten-free diet effects on fatigue in celiac disease: a prospective controlled study.

Introduction: Fatigue is a frequent complaint in patients with celiac disease. A gluten-free diet is the only established treatment for celiac disease, but how this diet influences fatigue is uncertain. We aimed to investigate fatigue prevalence, severity, and associated factors in patients with celiac disease, at diagnosis and at 1 year after commencing a gluten-free diet. Methods: 78 patients with serologically and histologically verified celiac disease, 78 age- and sex-matched healthy subjects. Primary endpoints were Fatigue Visual Analog Scale (fVAS), Fatigue Severity Scale (FSS), and inverted Vitality subscale of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36vs). Clinically relevant fatigue was defined as: FSS score ≥ 4, fVAS score ≥ 50 mm, or inverted SF-36vs score ≥ 65. Higher scores represented more fatigue. Results: Fatigue was reduced after a 12-month gluten-free diet. Median scores changed from 3.8 (interquartile range [IQR]: 2.2 to 4.8) to 1.9 (IQR: 1.4 to 3.5) for FSS, from 44.5 (IQR: 18.8 to 66.0) to 15.5 (IQR: 7.8 to 43.3) for fVAS, and from 65 (IQR: 40 to 75) to 35 (IQR: 25 to 55) for inverted SF-36vs (p < 0.001 for all). Fatigue prevalence also declined after treatment. However, scores were significantly higher in patients compared to control subjects. Higher fatigue scores were associated with depression and pain, but not with signs of disease activity or nutritional deficiency. Conclusion: At diagnosis, patients with celiac disease frequently had severe fatigue. Fatigue declined after a gluten-free diet, but it remained higher than that observed in healthy subjects. Clinical trial registration: ClinicalTrials.gov, Identifier NCT01551563.

High mobility group box 1 and a network of other biomolecules influence fatigue in patients with Crohn's disease.

BACKGROUND: Fatigue is common in patients with chronic inflammatory and autoimmune diseases, often with a severe impact on the patient's daily life. From a biological point of view, fatigue can be regarded as an element of the sickness behavior response, a coordinated set of responses induced by pathogens to enhance survival during an infection and immunological danger. The mechanisms are not fully understood but involve activation of the innate immune system, with pro-inflammatory cytokines, in particular interleukin (IL)-1ß, acting on cerebral neurons. These mechanisms are also active during chronic inflammatory conditions. High mobility group box 1 (HMGB1) protein has interleukin-1 like properties and is a strong inducer of innate immune responses. Its role in generation of fatigue is not clarified. Emerging evidence indicates that also other biomolecules may influence sickness behavior. We aimed to elucidate how HMGB1 influences fatigue in patients with Crohn's disease, and how the protein interacts with other candidate biomarkers of fatigue. METHODS: In 56 patients with newly diagnosed Crohn's disease, fatigue was evaluated using three different fatigue instruments: the fatigue visual analog scale (fVAS), Fatigue Severity Scale (FSS), and the vitality subscale of Medical Outcomes Study Short-Form Health Survey (SF-36vs). The biochemical markers IL-1 receptor antagonist (RA), soluble IL-1 receptor type 2 (sIL-RII), heat shock protein 90 alpha (HSP90α), HMGB1, anti-fully reduced (fr)HMGB1 antibodies (abs), hemopexin (HPX), and pigment epithelium-derived factor (PEDF) were measured in plasma. Multivariable regression and principal component analyses (PCA) were applied. RESULTS: Multivariable regression analyses revealed significant contributions to fatigue severity for HMGB1 in the FSS model, HSP90α in the fVAS model and IL-1RA in the SF-36vs model. Depression and pain scores contributed to all three models. In PCA, two components described 53.3% of the variation. The "inflammation and cellular stress dimension" was dominated by IL-1RA, sIL-1RII, HSP90α, HPX, and PEDF scores, where the "HMGB1 dimension" was dominated by HMGB1, anti-frHMGB1 abs, and fVAS scores. CONCLUSION: This study supports the hypothesis that HMGB1 and a network of other biomolecules influence fatigue severity in chronic inflammatory conditions. The well-known association with depression and pain is also acknowledged.

The Effect of Biological Treatment on Fatigue in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Fatigue is a frequent complaint in patients with inflammatory bowel disease. Biological drugs have demonstrated beneficial effects on some extraintestinal manifestations, but the effect on fatigue is not clear. OBJECTIVE: This study investigated the effects of biological and small molecule drugs approved for inflammatory bowel disease on fatigue. METHODS: We performed a systematic review and meta-analysis of randomized, placebo-controlled trials reporting Federal Drug Agency (FDA)-approved biological and small molecule drugs for use in ulcerative colitis and Crohn's disease in which measures of fatigue were recorded before and after treatment. Only induction studies were included. Maintenance studies were excluded. We searched Embase (Ovid), Medline (Ovid), PsycINFO (Ovid), Cinahl (EBSCOhost), Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov in May 2022. Risk of bias was analyzed using the Cochrane risk-of-bias tool. Standardized mean difference was used to measure the treatment effect. RESULTS: A total of seven randomized controlled trials composed of 3835 patients were included in the meta-analysis. All of the studies included patients with moderately to severely active ulcerative colitis or Crohn's disease. The studies used three different generic fatigue instruments: the Functional Assessment of Chronic Illness Therapy-Fatigue and the Short Form 36 Health Survey Vitality Subscale versions 1 and 2. Overall treatment with biological or small molecule agents showed a beneficial effect compared with placebo, with a standardized mean difference of 0.25 (95% confidence interval 0.15-0.34, p < 0.001). The effect was independent of type of drug or subtype of inflammatory bowel disease. DISCUSSION: The risk of bias was considered to be low for all domains except for missing outcome data. Even though the included studies were of high methodological quality, the review is limited by the small number of studies included and that the available studies were not designed to evaluate fatigue specifically. CONCLUSION: Biological and small molecule drugs used in inflammatory bowel disease have a consistent, though small, beneficial effect on fatigue.

Stratified genetic analysis reveals sex differences in MPO-ANCA-associated vasculitis.

OBJECTIVE: To identify and genetically characterize subgroups of patients with ANCA-associated vasculitides (AAV) based on sex and ANCA subtype. METHODS: A previously established SNP dataset derived from DNA sequencing of 1853 genes and genotyping of 1088 Scandinavian cases with AAV and 1589 controls was stratified for sex and ANCA subtype and analysed for association with five top AAV SNPs. rs9274619, a lead variant at the HLA-DQB1/HLA-DQA2 locus previously associated with AAV positive for myeloperoxidase (MPO)-ANCA, was analysed for association with the cumulative disease involvement of ten different organ systems. RESULTS: rs9274619 showed a significantly stronger association to MPO-ANCA-positive females than males [P = 2.0 × 10-4, OR = 2.3 (95% CI 1.5, 3.5)], whereas proteinase 3 (PR3)-ANCA-associated variants rs1042335, rs9277341 (HLA-DPB1/A1) and rs28929474 (SERPINA1) were equally associated with females and males with PR3-ANCA. In MPO-ANCA-positive cases, carriers of the rs9274619 risk allele were more prone to disease engagement of eyes [P = 0.021, OR = 11 (95% CI 2.2, 205)] but less prone to pulmonary involvement [P = 0.026, OR = 0.52 (95% CI 0.30, 0.92)]. Moreover, AAV with both MPO-ANCA and PR3-ANCA was associated with the PR3-ANCA lead SNP rs1042335 [P = 0.0015, OR = 0.091 (95% CI 0.0022, 0.55)] but not with rs9274619. CONCLUSIONS: Females and males with MPO-ANCA-positive AAV differ in genetic predisposition to disease, suggesting at least partially distinct disease mechanisms between the sexes. Double ANCA-positive AAV cases are genetically similar to PR3-ANCA-positive cases, providing clues to the clinical follow-up and treatment of these patients.

Strong Association of Combined Genetic Deficiencies in the Classical Complement Pathway With Risk of Systemic Lupus Erythematosus and Primary Sjögren's Syndrome.

OBJECTIVE: Complete genetic deficiency of the complement component C2 is a strong risk factor for monogenic systemic lupus erythematosus (SLE), but whether heterozygous C2 deficiency adds to the risk of SLE or primary Sjögren's syndrome (SS) has not been studied systematically. This study was undertaken to investigate potential associations of heterozygous C2 deficiency and C4 copy number variation with clinical manifestations in patients with SLE and patients with primary SS. METHODS: The presence of the common 28-bp C2 deletion rs9332736 and C4 copy number variation was examined in Scandinavian patients who had received a diagnosis of SLE (n = 958) or primary SS (n = 911) and in 2,262 healthy controls through the use of DNA sequencing. The concentration of complement proteins in plasma and classical complement function were analyzed in a subgroup of SLE patients. RESULTS: Heterozygous C2 deficiency-when present in combination with a low C4A copy number-substantially increased the risk of SLE (odds ratio [OR] 10.2 [95% confidence interval (95% CI) 3.5-37.0]) and the risk of primary SS (OR 13.0 [95% CI 4.5-48.4]) when compared to individuals with 2 C4A copies and normal C2. For patients heterozygous for rs9332736 with 1 C4A copy, the median age at diagnosis was 7 years earlier in patients with SLE and 12 years earlier in patients with primary SS when compared to patients with normal C2. Reduced C2 levels in plasma (P = 2 × 10-9 ) and impaired function of the classical complement pathway (P = 0.03) were detected in SLE patients with heterozygous C2 deficiency. Finally, in a primary SS patient homozygous for C2 deficiency, we observed low levels of anti-Scl-70, which suggests a risk of developing systemic sclerosis or potential overlap between primary SS and other systemic autoimmune diseases. CONCLUSION: We demonstrate that a genetic pattern involving partial deficiencies of C2 and C4A in the classical complement pathway is a strong risk factor for SLE and for primary SS. Our results emphasize the central role of the complement system in the pathogenesis of both SLE and primary SS.

Fatigue: a frequent and biologically based phenomenon in newly diagnosed celiac disease.

Fatigue is increasingly recognized as a major complaint in patients with chronic inflammatory and autoimmune diseases. Although fatigue is assumed to represent a significant problem in celiac disease, existing knowledge is scarce, and opinions are conflicting. This study aimed to investigate the prevalence and severity of fatigue in patients with newly diagnosed celiac disease and compare it with healthy control subjects. Ninety patients with newly diagnosed celiac disease were compared with 90 age- and sex-matched healthy subjects. The primary endpoints were fatigue severity as measured by: the fatigue Visual Analog Scale (fVAS), the Fatigue Severity Scale (FSS), and the inverted Vitality subscale of the MOS36 (SF-36vs). Higher scores indicate more severe fatigue. Clinically relevant fatigue was determined using predefined cut-off values. Secondary endpoints were the associations between fatigue, and sex, age, depression, pain, and selected biochemical variables. The median (IQR) fVAS-scores were 43.0 (18.0-64.5) in patients, and 9.0 (2.0-16.0) in the control group (p < 0.001); and the FSS scores 3.8 (2.0-4.8) in patients, and 1.4 (1.0-1.9) in control subjects (p < 0.001). Inverted SF-36vs scores had a mean (SD) value of 58.8 (23.6) in patients, and 29.7 (14.3) in healthy subjects (p < 0.001). The presence of clinically relevant fatigue ranged from 41 to 50% in patients. Increased fatigue severity was associated with female sex, younger age, and elevated pain and depression scores, but not with levels of selected biochemical variables, including hemoglobin. Fatigue is a severe and frequent phenomenon in patients with untreated celiac disease.

Complement C4 Copy Number Variation is Linked to SSA/Ro and SSB/La Autoantibodies in Systemic Inflammatory Autoimmune Diseases.

OBJECTIVE: Copy number variation of the C4 complement components, C4A and C4B, has been associated with systemic inflammatory autoimmune diseases. This study was undertaken to investigate whether C4 copy number variation is connected to the autoimmune repertoire in systemic lupus erythematosus (SLE), primary Sjögren's syndrome (SS), or myositis. METHODS: Using targeted DNA sequencing, we determined the copy number and genetic variants of C4 in 2,290 well-characterized Scandinavian patients with SLE, primary SS, or myositis and 1,251 healthy controls. RESULTS: A prominent relationship was observed between C4A copy number and the presence of SSA/SSB autoantibodies, which was shared between the 3 diseases. The strongest association was detected in patients with autoantibodies against both SSA and SSB and 0 C4A copies when compared to healthy controls (odds ratio [OR] 18.0 [95% confidence interval (95% CI) 10.2-33.3]), whereas a weaker association was seen in patients without SSA/SSB autoantibodies (OR 3.1 [95% CI 1.7-5.5]). The copy number of C4 correlated positively with C4 plasma levels. Further, a common loss-of-function variant in C4A leading to reduced plasma C4 was more prevalent in SLE patients with a low copy number of C4A. Functionally, we showed that absence of C4A reduced the individuals' capacity to deposit C4b on immune complexes. CONCLUSION: We show that a low C4A copy number is more strongly associated with the autoantibody repertoire than with the clinically defined disease entities. These findings may have implications for understanding the etiopathogenetic mechanisms of systemic inflammatory autoimmune diseases and for patient stratification when taking the genetic profile into account.

Fatigue and expression of heat-shock protein genes in plaque psoriasis.

BACKGROUND: Chronic fatigue is common in patients with psoriasis, and heat-shock proteins (HSPs) have been suggested to influence fatigue. AIM: To evaluate gene expression patterns of selected HSPs in patients with psoriasis with high vs. low fatigue. METHODS: Fatigue was assessed using the fatigue Visual Analogue Scale, and disease activity by the Psoriasis Area and Severity Index. Peripheral blood transcriptional profiling was performed using RNA sequencing (RNA-seq) of HSP genes from 10 patients with high fatigue, and compared with 10 patients with low fatigue. HSPB11, HSPBAP1, HSPA14, HSPA9P1, HSP90B1 and HSP90AB1 contributed most to separation of the two groups in a principal components analysis. Four of these genes (HSPB11, HSPA14, HSP90B1 and HSP90AB1) were further investigated by real-time reverse transcription quantitative PCR (RT-qPCR) in 20 patients with high- and 20 patients with low-fatigue scores. RESULTS: Both RNA-seq and RT-qPCR analyses revealed a tendency to higher expression levels of HSPB11 and lower expression of HSP90B1 in the high- vs. the low-fatigue group. Psoriasis disease activity had no influence on the expression levels of the studied HSP genes. CONCLUSION: Overall, the results suggest that some HSPs are involved in generation of fatigue in psoriasis, supporting the hypothesis that downregulatory innate immune responses influence fatigue.

Identification and functional characterization of a novel susceptibility locus for small vessel vasculitis with MPO-ANCA.

OBJECTIVE: To identify and characterize genetic loci associated with the risk of developing ANCA-associated vasculitides (AAV). METHODS: Genetic association analyses were performed after Illumina sequencing of 1853 genes and subsequent replication with genotyping of selected single nucleotide polymorphisms in a total cohort of 1110 Scandinavian cases with granulomatosis with polyangiitis or microscopic polyangiitis, and 1589 controls. A novel AAV-associated single nucleotide polymorphism was analysed for allele-specific effects on gene expression using luciferase reporter assay. RESULTS: PR3-ANCA+ AAV was significantly associated with two independent loci in the HLA-DPB1/HLA-DPA1 region [rs1042335, P = 6.3 × 10-61, odds ratio (OR) 0.10; rs9277341, P = 1.5 × 10-44, OR 0.22] and with rs28929474 in the SERPINA1 gene (P = 2.7 × 10-10, OR 2.9). MPO-ANCA+ AAV was significantly associated with the HLA-DQB1/HLA-DQA2 locus (rs9274619, P = 5.4 × 10-25, OR 3.7) and with a rare variant in the BACH2 gene (rs78275221, P = 7.9 × 10-7, OR 3.0), the latter a novel susceptibility locus for MPO-ANCA+ granulomatosis with polyangiitis/microscopic polyangiitis. The rs78275221-A risk allele reduced luciferase gene expression in endothelial cells, specifically, as compared with the non-risk allele. CONCLUSION: We identified a novel susceptibility locus for MPO-ANCA+ AAV and propose that the associated variant is of mechanistic importance, exerting a regulatory function on gene expression in specific cell types.

The influence of disease activity on fatigue in patients with ulcerative colitis - a longitudinal study.

OBJECTIVE: The relationship between the disease activity of ulcerative colitis and fatigue is unclear. We investigated how reaching deep remission versus remaining in active disease influenced the severity of fatigue. MATERIALS AND METHODS: We included 149 consecutive patients in a longitudinal study. Patients were re-examined after 3 months of conventional treatment and dichotomized into A: Active disease or B: Deep remission. The Partial Mayo Score (PMS) was recorded in all patients. Fatigue was rated using the fatigue visual analog scale (fVAS), Fatigue Severity Scale (FSS), and Short Form-36 Vitality Subscale (SF-36vs). A control group of 22 age and sex-matched healthy subjects were included as controls for patients reaching deep remission. RESULTS: After 3 months there were no significant differences in fVAS, FSS and SF-36vs scores in patients with active disease compared to patients reaching deep remission, when adjusting for baseline fatigue scores. Patients in remission based on MES-UC scores had no significant reduction in fatigue scores, whereas patients in remission based on PMS had all three fatigue scores reduced. However, patients reaching deep remission still had higher fVAS and lower SF-36vs scores compared to healthy control subjects. CONCLUSIONS: After 3 months of conventional treatment there were no differences in fatigue severity in patients reaching deep remission compared with patients still having active disease. Fatigue was more pronounced in patients in deep remission than in healthy subjects, and was associated with subjective and not objective measures of disease activity. This indicates that other potent factors than inflammation influence fatigue in UC.

Neurofilament light in plasma is a potential biomarker of central nervous system involvement in systemic lupus erythematosus.

BACKGROUND: Neuropsychiatric manifestations (NP) are common in systemic lupus erythematosus (SLE). However, the pathophysiological mechanisms are not completely understood. Neurofilament light protein (NfL) is part of the neuronal cytoskeleton. Increased NfL concentrations, reflecting neurodegeneration, is observed in cerebrospinal fluid (CSF) in several neurodegenerative and neuroinflammatory conditions. We aimed to explore if plasma NfL could serve as a biomarker for central nervous system (CNS) involvement in SLE. METHODS: Sixty-seven patients with SLE underwent neurological examination; 52 underwent lumbar puncture, while 62 underwent cerebral magnetic resonance imaging (MRI). We measured selected auto-antibodies and other laboratory variables postulated to have roles in NP pathophysiology in the blood and/or CSF. We used SPM12 software for MRI voxel-based morphometry. RESULTS: Age-adjusted linear regression analyses revealed increased plasma NfL concentrations with increasing creatinine (ß = 0.01, p < 0.001) and Q-albumin (ß = 0.07, p = 0.008). We observed higher plasma NfL concentrations in patients with a history of seizures (ß = 0.57, p = 0.014), impaired motor function (ß = 0.36, p = 0.008), increasing disease activity (ß = 0.04, p = 0.008), and organ damage (ß = 0.10, p = 0.002). Voxel-based morphometry suggested an association between increasing plasma NfL concentrations and the loss of cerebral white matter in the corpus callosum and hippocampal gray matter. CONCLUSION: Increased plasma NfL concentrations were associated with some abnormal neurological, cognitive, and neuroimaging findings. However, plasma NfL was also influenced by other factors, such as damage accrual, creatinine, and Q-albumin, thereby obscuring the interpretation of how plasma NfL reflects CNS involvement. Taken together, NfL in CSF seems a better marker of neuronal injury than plasma NfL in patients with SLE.

Genetic variants at the RTP4/MASP1 locus are associated with fatigue in Scandinavian patients with primary Sjögren's syndrome.

OBJECTIVES: Fatigue is common and severe in primary Sjögren's syndrome (pSS). The aim of this study was to identify genetic determinants of fatigue in pSS through a genome-wide association study. METHODS: Patients with pSS from Norway, Sweden, UK and USA with fatigue and genotype data available were included. After genotype imputation and quality control, 682 patients and 4 966 157 genetic markers were available. Association analysis in each cohort using linear regression with fatigue as a continuous variable and meta-analyses between the cohorts were performed. RESULTS: Meta-analysis of the Norwegian and Swedish cohorts identified five polymorphisms within the same linkage disequilibrium block at the receptor transporter protein 4 (RTP4)/MASP1 locus associated with fatigue with genome-wide significance (GWS) (p<5×10-8). Patients homozygous for the major allele scored 25 mm higher on the fatigue Visual Analogue Scale than patients homozygous for the minor allele. There were no variants associated with fatigue with GWS in meta-analyses of the US/UK cohorts, or all four cohorts. RTP4 expression in pSS B cells was upregulated and positively correlated with the type I interferon score. Expression quantitative trait loci effects in whole blood for fatigue-associated variants at RTP4/MASP1 and levels of RTP4 and MASP1 expression were identified. CONCLUSION: Genetic variations at RTP4/MASP1 are associated with fatigue in Scandinavian pSS patients. RTP4 encodes a Golgi chaperone that influences opioid pain receptor function and MASP1 is involved in complement activation. These results add evidence for genetic influence over fatigue in pSS.

DNA Methylation-Based Interferon Scores Associate With Sub-Phenotypes in Primary Sjögren's Syndrome.

Primary Sjögren's syndrome (pSS) is an autoimmune inflammatory disease with profound clinical heterogeneity, where excessive activation of the type I interferon (IFN) system is considered one of the key mechanisms in disease pathogenesis. Here we present a DNA methylation-based IFN system activation score (DNAm IFN score) and investigate its potential associations with sub-phenotypes of pSS. The study comprised 100 Swedish patients with pSS and 587 Swedish controls. For replication, 48 patients with pSS from Stavanger, Norway, were included. IFN scores were calculated from DNA methylation levels at the IFN-induced genes RSAD2, IFIT1 and IFI44L. A high DNAm IFN score, defined as > meancontrols +2SDcontrols (IFN score >4.4), was observed in 59% of pSS patients and in 4% of controls (p=1.3x10-35). Patients with a high DNAm IFN score were on average seven years younger at symptom onset (p=0.017) and at diagnosis (p=3x10-3). The DNAm IFN score levels were significantly higher in pSS positive for both SSA and SSB antibodies compared to SSA/SSB negative patients (pdiscovery=1.9x10-8, preplication=7.8x10-4). In patients positive for both SSA subtypes Ro52 and Ro60, an increased score was identified compared to single positive patients (p=0.022). Analyzing the discovery and replication cohorts together, elevated DNAm IFN scores were observed in pSS with hypergammaglobulinemia (p=2x10-8) and low C4 (p=1.5x10-3) compared to patients without these manifestations. Patients < 70 years with ongoing lymphoma at DNA sampling or lymphoma at follow-up (n=7), presented an increased DNAm IFN score compared to pSS without lymphoma (p=0.025). In conclusion, the DNAm-based IFN score is a promising alternative to mRNA-based scores for identification of patients with activation of the IFN system and may be applied for patient stratification guiding treatment decisions, monitoring and inclusion in clinical trials.

Sample Preparation Strategies for Antibody-Free Quantitative Analysis of High Mobility Group Box 1 Protein.

Sickness behavior and fatigue are induced by cerebral mechanisms involving inflammatory cytokines. High mobility group box 1 (HMGB1) is an alarmin, and a potential key player in this process. Reliable quantification methods for total HMGB1 and its redox variants must be established in order to clearly understand how it functions. Current methods pose significant challenges due to interference from other plasma proteins and autoantibodies. We aimed to develop an antibody-free sample preparation method followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) to measure HMGB1 in human plasma. Different methods were applied for the removal of interfering proteins and the enrichment of HMGB1 from spiked human plasma samples. A comparison of methods showed an overall low extraction recovery (<40%), probably due to the stickiness of HMGB1. Reversed-phase liquid chromatography separation of intact proteins in diluted plasma yielded the most promising results. The method produced an even higher degree of HMGB1 purification than that observed with immunoaffinity extraction. Detection sensitivity needs to be further improved for the measurement of HMGB1 in patient samples. Nevertheless, it has been demonstrated that a versatile and fully antibody-free sample preparation method is possible, which could be of great use in further investigations.

Anti-HMGB1 auto-Abs influence fatigue in patients with Crohn's disease.

Fatigue is common in all chronic inflammatory and autoimmune diseases. A conceptual model for understanding the biological basis of fatigue describes it as being a part of the sickness behaviour response generated by pro-inflammatory cytokines and other mediators. We hypothesised that the pro-inflammatory high mobility group box 1 (HMGB1) protein is a fatigue-inducing molecule and that auto-Abs against HMGB1 reduce fatigue. We measured Abs against disulphide (ds) HMGB1 and fully reduced (fr) HMGB1 in plasma from 57 patients with Crohn's disease. Fatigue was rated using the fatigue visual analogue scale (fVAS) and disease activity with faecal calprotectin, C-reactive protein and the Simple Endoscopic Score for Crohn's disease. Multivariable regression models identified anti-dsHMGB1 and anti-frHMGB1 Abs as the strongest contributing factors for fVAS scores (B = -29.10 (P = 0.01), R2 = 0.17, and B = -17.77 (P = 0.01), R2 = 0.17, respectively). Results indicate that anti-HMGB1 auto-Abs alleviate fatigue possibly by down-regulating HMGB1-induced sickness behaviour.