Roald Omdal

Variants at multiple loci implicated in both innate and adaptive immune responses are associated with Sjögren’s syndrome

Sjögrens syndrome is a common autoimmune disease (affecting ∼0.7% of European Americans) that typically presents as keratoconjunctivitis sicca and xerostomia. Here we report results of a large-scale association study of Sjögrens syndrome. In addition to strong association within the human leukocyte antigen (HLA) region at 6p21 (Pmeta = 7.65 × 10−114), we establish associations with IRF5-TNPO3 (Pmeta = 2.73 × 10−19), STAT4 (Pmeta = 6.80 × 10−15), IL12A (Pmeta = 1.17 × 10−10), FAM167A-BLK (Pmeta = 4.97 × 10−10), DDX6-CXCR5 (Pmeta = 1.10 × 10−8) and TNIP1 (Pmeta = 3.30 × 10−8). We also observed suggestive associations (Pmeta < 5 × 10−5) with variants in 29 other regions, including TNFAIP3, PTTG1, PRDM1, DGKQ, FCGR2A, IRAK1BP1, ITSN2 and PHIP, among others. These results highlight the importance of genes that are involved in both innate and adaptive immunity in Sjögrens syndrome.

Neuropsychiatric disturbances in SLE are associated with antibodies against NMDA receptors

To determine whether neuropsychiatric manifestations in patients with systemic lupus erythematosus (SLE) are influenced by antibodies against the human N‐methyl‐d‐aspartate (NMDA) receptor types NR2a or NR2b. A decapeptide was synthesized containing a sequence motif present in the extracellular ligand‐binding domain of NMDA receptors NR2a and NR2b, bound by the monoclonal murine anti‐DNA antibody R4A. In an ELISA with the murine monoclonal R4v as positive control, plasma samples of 57 patients with SLE were examined for the anti‐peptide (anti‐NR2) antibody after the patients had been subjected to comprehensive psychological and cognitive testing. Poor performance on the Visual Paired Associates test (immediate), the Grooved Pegboard test, as well as high scores on the Beck Depression Inventory, and scales D‐2 (depression), Pd‐4 (psychopathic deviate), Sc‐8 (schizophrenia), and Ma‐9 (hypomania) of the MMPI‐2 were significantly associated with elevated levels of anti‐NR2 antibodies. The findings in several domains indicate an association between anti‐NR2 antibodies and depressed mood in addition to decreased short‐time memory and learning. Antibodies to NMDA receptors thus may represent one of several mechanisms for cerebral dysfunction in patients with SLE.

The effect of age and gender on epidermal nerve fiber density

Objective: Sensory neuropathies often involve small-diameter myelinated and unmyelinated nerve fibers, and neurologic and electrophysiologic findings may be normal unless larger nerve fibers are involved. The small (intra)epidermal nerve fibers (ENFs) now can be visualized with immunohistochemical techniques using the panaxonal marker anti-protein gene product 9.5 (PGP 9.5). Using this technique, the authors have established a reference range for ENF in a healthy white population and evaluated the reliability of the method. Methods: Two punch biopsies, 3 mm in diameter, were taken from the distal part of the leg in 106 healthy volunteers (mean age, 49.0 ± 19.6 years). Fifty-micrometer frozen thick sections were incubated with rabbit polyclonal antibodies to human PGP 9.5. The number of ENF/mm then was reported as the mean of counts in six sections (three sections from each of the two biopsies). Results: The mean number of ENFs was 12.4 ± 4.6 mm. In a multiple regression model, the density of ENF depended on age and gender (Y = 13.92 + 2.25 (gender) − 0.06 × age). The mean difference in ENF by intraobserver analysis was 0.2 ± 1.2 ENF/mm, and by interobserver analysis, it was 0.4 ± 1.5 fibers/mm. Conclusion: Normal means and ranges for the density of epidermal nerve fibers in a reference population have been established. The density of epidermal nerve fibers decreases with age and is lower in men compared with women. Intraobserver and interobserver analysis proves the reliability of the method.

Anti-CD20 therapy of treatment-resistant Wegener's granulomatosis: favourable but temporary response.

Rituximab is a genetically engineered chimeric monoclonal immunoglobulin (Ig)G1 antibody. It binds the CD20 trans‐membrane surface antigen expressed by mature B cells but not by antibody secreting plasma cells, and removes the cells by activating complement, inducing cell‐mediated lysis, and by apoptosis 1, 2. Mainly used for the treatment of non‐Hodgkins lymphomas, rituximab has recently been tried with favourable responses in rheumatoid arthritis, systemic lupus erythematosus, and other chronic immunological diseases 3–6. Wegeners granulomatosis (WG) is a granulomatous vasculitis with high morbidity and mortality 7, 8. It is thought that anti‐neutrophil cytoplasmatic antibodies (ANCA) with specificity for proteinase 3 (PR3) are possibly involved in the pathogenesis of the disease 9, 10. Conventional therapy with cyclophosphamide and corticosteroids generally succeeds in inducing remission, but relapses frequently follow. Among the biological agents, tumour necrosis factor‐α (TNF‐α) inhibitors have been tried with some success 11. Based on a case report 12 we recently treated three refractory WG patients with rituximab and achieved almost complete but temporary remission. CD20+ cells disappeared rapidly in peripheral blood, only to rise prior to subsequent disease flares occurring at 34, 63, and 54 weeks, respectively (Figure 1). A new flare occurred in one patient at 86 weeks. At the end of the observation periods (54, 102, and 120 weeks), only one patient had proteinuria. Chest radiographs became normal in two patients, while infiltrates remained unchanged in the third. Granulomatous retro‐orbital or sinus masses in two patients seemed unresponsive to therapy. Figure 1. Numbers of CD20+ cells in peripheral blood. Slim and broad arrows denote disease flares and rituximab courses, respectively. The first infusion of rituximab is at week 0.

No effect of supplementation with cholecalciferol on cytokines and markers of inflammation in overweight and obese subjects.

Epidemiological studies indicate a relation between vitamin D status and autoimmune diseases, and in vitro studies demonstrate an effect of 1,25-dihydroxyvitamin D on immune activation. However, the relation between serum levels of 25-hydroxyvitamin D (25(OH)D) and the effect of vitamin D supplementation on serum levels of cytokines are not settled. In the present study interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17, intercellular adhesion molecule-1, interferon-gamma, monocyte chemotactic protein-1, and high sensitivity C-reactive protein, were measured in 437 overweight subjects and 324 completed a one year intervention with 40,000 IU vitamin D per week (group DD), 20,000 IU vitamin D per week (group DP), or placebo (group PP). No consistent relations between serum levels of the cytokines and 25(OH)D were found at baseline. In the intervention study, there was no difference in delta values (value at end of study minus value at inclusion) between the three groups regarding the individual cytokines measured, nor was there any indication of a polarization of the T cells towards a Th2 dominant type. In conclusion, we were not able to demonstrate with certainty any significant relation between serum levels of 25(OH)D levels and a number of cytokines and markers of inflammation.

Biological mechanisms of chronic fatigue

Chronic fatigue is a common, poorly understood and disabling phenomenon in many diseases. We aim to provide an overview of fatigue in chronic autoimmune and inflammatory disease. Fatigue measurement, prevalence and confounding factors such as depression, sleep disorders and pain are reviewed in the first half of the article. In the second half of the article, we describe explanatory models of fatigue and fatigue signalling, with an emphasis on cytokines and sickness behaviour, oxidative stress, mitochondrial dysfunction and the impact of certain genes on fatigue.

Association of EBF1 , FAM167A(C8orf13)-BLK and TNFSF4 gene variants with primary Sjögren's syndrome

We performed a candidate gene association study in 540 patients with primary Sjögrens Syndrome (SS) from Sweden (n=344) and Norway (n=196) and 532 controls (n=319 Swedish, n=213 Norwegian). A total of 1139 single-nucleotide polymorphisms (SNPs) in 84 genes were analyzed. In the meta-analysis of the Swedish and Norwegian cohorts, we found high signals for association between primary SS and SNPs in three gene loci, not previously associated with primary SS. These are the early B-cell factor 1 (EBF1) gene, P=9.9 × 10−5, OR 1.68, the family with sequence similarity 167 member A–B-lymphoid tyrosine kinase (FAM167A–BLK) locus, P=4.7 × 10−4, OR 1.37 and the tumor necrosis factor superfamily (TNFSF4=Ox40L) gene, P=7.4 × 10−4, OR 1.34. We also confirmed the association between primary SS and the IRF5/TNPO3 locus and the STAT4 gene. We found no association between the SNPs in these five genes and the presence of anti-SSA/anti-SSB antibodies. EBF1, BLK and TNFSF4 are all involved in B-cell differentiation and activation, and we conclude that polymorphisms in several susceptibility genes in the immune system contribute to the pathogenesis of primary SS.

Improved detection of advanced oxidation protein products in plasma

BACKGROUND Oxidative stress has been associated with many diseases and can among others be assessed as increased levels of advanced oxidation protein products (AOPP). Current AOPP methods suffer from poor reproducibility and accuracy due to precipitation of lipids in plasma samples. We therefore aimed to develop a robust method in which plasma lipids are solubilized. METHODS Plasma was diluted with citric acid, and AOPP measured as absorbance at 340 nm. The method was optimized and validated, and then used to analyze AOPP levels in plasma from healthy control subjects (HC), and in three patients groups; chronic kidney disease (CKD), primary Sjögrens Syndrome (pSS) and systemic lupus erythematosus (SLE). RESULTS AOPP was detected with improved precision compared to established methods where lipids precipitate. Within- and between days variations were less than 1.4% and 2.2%, respectively. A control chart was established and the long-term reproducibility followed over six months. CONCLUSIONS This improved method detects plasma AOPP with significantly better reproducibility and accuracy compared to previously reported methods. Solubilization of plasma lipids before spectrophotometric measure of AOPP levels is novel. It prevents both loss of lipoproteins due to precipitation and overestimation as a result of light scattering.

Interleukin-1 Inhibition and Fatigue in Primary Sjögren's Syndrome – A Double Blind, Randomised Clinical Trial

Objectives Fatigue is a major cause of disability in primary Sjögrens syndrome (pSS). Fatigue has similarities with sickness behaviour in animals; the latter mediated by pro-inflammatory cytokines, in particular interleukin (IL)-1, acting on neuronal brain cells. We hypothesised that IL-1 inhibition might improve fatigue in pSS patients; thus, we examined the effects and safety of an IL-1 receptor antagonist (anakinra) on fatigue. Methods Twenty-six pSS patients participated in a double-blind, placebo-controlled parallel group study. Patients were randomised to receive either anakinra or a placebo for four weeks. Fatigue was evaluated by a fatigue visual analogue scale and the Fatigue Severity Scale. The primary outcome measure was a group-wise comparison of the fatigue scores at week 4, adjusted for baseline values. Secondary outcome measures included evaluation of laboratory results and safety. The proportion of patients in each group who experienced a 50% reduction in fatigue was regarded as a post-hoc outcome. All outcomes were measured at week 4. Results There was no significant difference between the groups in fatigue scores at week 4 compared to baseline after treatment with anakinra. However, six out of 12 patients on anakinra versus one out of 13 patients on the placebo reported a 50% reduction in fatigue VAS (p = 0.03). There were two serious adverse events in each group. Conclusions This randomised, double-blind, placebo-controlled trial of IL-1 blockade did not find a significant reduction in fatigue in pSS in its primary endpoint. A 50% reduction in fatigue was analysed post-hoc, and significantly more patients on the active drug than on placebo reached this endpoint. Although not supported by the primary endpoint, this may indicate that IL-1 inhibition influences fatigue in patients with pSS. Trial registration ClinicalTrials.gov NCT00683345

Neuropsychiatric syndromes in patients with systemic lupus erythematosus and primary Sjögren syndrome: a comparative population-based study

Objectives: To compare the prevalence and pattern of neuropsychiatric (NP) syndromes observed in systemic lupus erythematosus (SLE) to patients with Primary Sjögren syndrome (PSS) using the American College of Rheumatology (ACR) criteria for the 19 NP syndromes seen in SLE. Methods: A population-based study was conducted including 68 patients with SLE (mean (SD) age 43.8 (13.6) years) and 72 with PSS (age 57.8 (13.0) years). Specialists in internal medicine, neurology and neuropsychology performed standardised examinations. Cerebral MRI scans and neurophysiological studies were performed in all patients. Results: Similar prevalences in SLE and PSS were observed for headaches (87% vs 78%, p = 0.165), cognitive dysfunction (46% vs 50%, p = 0.273), mood disorders (26% vs 33%, p = 0.376), anxiety disorders (12% vs 4%, p = 0.095), cranial neuropathy (1% vs 4%, p = 0.339) and seizure disorders (7% vs 3%, p = 0.208). Cerebrovascular disease was more common in SLE than PSS (12% vs 3%, p = 0.049); but mononeuropathy (0% vs 8%, p = 0.015) and polyneuropathy (18% vs 56%, p<0.001) were less common in SLE than PSS. Other syndromes were rare or absent in both patient groups. Conclusions: Headache, cognitive dysfunction and mood disorders are common in both diseases, but otherwise there are distinct differences in NP involvement, with cerebrovascular diseases more prevalent in SLE and neuropathies more common in PSS. This indicates that some NP disease mechanisms are shared while others differ between the two diseases.