Jon Lampa

Longitudinal analysis of citrullinated protein/peptide antibodies (anti-CP) during 5 year follow up in early rheumatoid arthritis: anti-CP status predicts worse disease activity and greater radiological progression

Objective: To study serum levels of citrullinated protein/peptide antibodies (anti-CP) during up to 5 years’ follow up of patients with early rheumatoid arthritis (RA), and to relate serum levels to disease course and to treatments in clinical practice. Methods: 279 patients with early RA were followed up with clinical investigations, radiographs, and measurement of anti-CP at baseline and after 3 months, 1, 2, 3, and 5 years. Results: 160/279 (57.3%) patients were anti-CP positive at the first visit (mean 5 months after first symptoms). During follow up only 11/279 (3.9%) of the patients changed their anti-CP status. Anti-CP levels fell significantly during the first year, and this drop correlated with the extent of sulfasalazine treatment but not with other drugs or clinical indices. Anti-CP positive and negative patients had similar disease activities at baseline, but during follow up the anti-CP positive patients had worse clinical disease and greater radiological progression, despite at least equally intensive antirheumatic treatment. Conclusions: Anti-CP are stable during the first 5 years of RA, suggesting that events before rather than after onset of clinical manifestations of disease determine this phenotype. The presence of anti-CP at diagnosis predicts a less favourable disease course and greater radiological progression despite antirheumatic treatment, but subsequent changes in antibody levels do not reflect changes in disease activity. Taken together, these observations suggest that anti-CP positive RA is a distinct clinical and pathophysiological entity.

Genetic markers for the efficacy of tumour necrosis factor blocking therapy in rheumatoid arthritis

Background: Rheumatoid arthritis (RA) is a genetically complex disease where the response to different treatments varies greatly between different patients. This is the case with the tumour necrosis factor (TNF) blocking agents, where 20–40% of patients have been described as non-responders. No predictive markers exist as yet for the prognosis of response. Objective: To analyse whether polymorphisms of several cytokine genes are associated with the responsiveness to TNF blockade with etanercept. Methods: 123 patients with active RA were treated with etanercept and response rates were determined after three months using American College of Rheumatology (ACR)20 and disease activity score (DAS)28 response criteria. Genotyping was done for TNF (−308 TNFA), interleukin (IL)10 (−1087 IL10), transforming growth factor (TGF)β1 (codon 25 TGFB1), and IL1 receptor antagonist (intron 2 IL1RN). Results: 24 patients (20%) were defined as non-responders owing to their failure to fulfil any of the ACR20 or DAS28 response criteria. None of the recorded alleles was alone significantly associated with responsiveness to treatment. However, a certain combination of alleles (−308 TNF1/TNF1 and −1087 G/G) was associated with good responsiveness to etanercept (p<0.05). In addition, a combination of alleles influencing interleukin 1 receptor antagonist (IL1Ra) and TGFβ1 production (A2 allele for IL1RN and rare C allele in codon 25 of TGFB1 gene) was associated with non-responsiveness (p<0.05). Conclusion: Genetic polymorphisms, which may influence the balance of pro- and anti-inflammatory cytokines of relevance for the course of RA, are associated with clinical responsiveness to etanercept treatment.

Blood autoantibody and cytokine profiles predict response to anti-tumor necrosis factor therapy in rheumatoid arthritis

IntroductionAnti-TNF therapies have revolutionized the treatment of rheumatoid arthritis (RA), a common systemic autoimmune disease involving destruction of the synovial joints. However, in the practice of rheumatology approximately one-third of patients demonstrate no clinical improvement in response to treatment with anti-TNF therapies, while another third demonstrate a partial response, and one-third an excellent and sustained response. Since no clinical or laboratory tests are available to predict response to anti-TNF therapies, great need exists for predictive biomarkers.MethodsHere we present a multi-step proteomics approach using arthritis antigen arrays, a multiplex cytokine assay, and conventional ELISA, with the objective to identify a biomarker signature in three ethnically diverse cohorts of RA patients treated with the anti-TNF therapy etanercept.ResultsWe identified a 24-biomarker signature that enabled prediction of a positive clinical response to etanercept in all three cohorts (positive predictive values 58 to 72%; negative predictive values 63 to 78%).ConclusionsWe identified a multi-parameter protein biomarker that enables pretreatment classification and prediction of etanercept responders, and tested this biomarker using three independent cohorts of RA patients. Although further validation in prospective and larger cohorts is needed, our observations demonstrate that multiplex characterization of autoantibodies and cytokines provides clinical utility for predicting response to the anti-TNF therapy etanercept in RA patients.

Evidence of central inflammation in fibromyalgia — Increased cerebrospinal fluid interleukin-8 levels

Activation of glia cells resulting in intrathecal elevation of cytokines and chemokines has been hypothesized in chronic pain syndromes such as fibromyalgia. To our knowledge, this is the first study assessing intrathecal concentrations of pro-inflammatory substances in fibromyalgia. We report elevated cerebrospinal fluid and serum concentrations of interleukin-8, but not interleukin-1beta, in FM patients. This profile is in accordance with FM symptoms being mediated by sympathetic activity rather than dependent on prostaglandin associated mechanisms and supports the hypothesis of glia cell activation in response to pain mechanisms.

Increased proportion of CD56bright natural killer cells in active and inactive systemic lupus erythematosus

Natural killer (NK) cells belong to the innate immune system but can also affect adaptive immune reactions. This immune regulatory function is often ascribed to the CD56bright subpopulation of NK cells that is prevalent in secondary lymphoid tissues and has potent cytokine‐producing ability. The NK cells have been described as affecting autoimmune disease and stimulating B‐cell production of antibodies, but their role in systemic lupus erythematosus (SLE) pathology has not been extensively studied. We have studied NK cells in SLE, a B‐cell‐driven systemic autoimmune disease, and phenotypically characterized peripheral blood NK cells in comparison to NK cells from patients with immunoglobulin A nephritis, rheumatoid arthritis and healthy individuals. We have found an increased proportion of CD56bright NK cells in SLE, regardless of disease activity. We detected a somewhat increased expression of the activating receptor NKp46/CD335 on NK cells from SLE patients, although neither the percentage of NK cells of all lymphocytes nor the expression of other NK receptors analysed (LIR‐1/CD85j, CD94, NKG2C/CD159c, NKG2D/CD314, NKp30/CD337, NKp44/CD336, CD69) differed between patient groups. We show that type I interferon, a proinflammatory cytokine known to be abundant in SLE, can cause increases of CD56bright NK cells in vitro. We confirmed that serum levels of interferon‐α were increased in active, but not in inactive, disease in the SLE patient group. In conclusion, we found an increased proportion of CD56bright NK cells in the blood of SLE patients, although it remains to be examined whether and how this relates to the disease process.

Peripheral inflammatory disease associated with centrally activated IL-1 system in humans and mice

During peripheral immune activation caused by an infection or an inflammatory condition, the innate immune response signals to the brain and causes an up-regulation of central nervous system (CNS) cytokine production. Central actions of proinflammatory cytokines, in particular IL-1β, are pivotal for the induction of fever and fatigue. In the present study, the influence of peripheral chronic joint inflammatory disease in rheumatoid arthritis (RA) on CNS inflammation was investigated. Intrathecal interleukin (IL)-1β concentrations were markedly elevated in RA patients compared with controls or with patients with multiple sclerosis. Conversely, the anti-inflammatory IL-1 receptor antagonist and IL-4 were decreased in RA cerebrospinal fluid (CSF). Tumor necrosis factor and IL-6 levels in the CSF did not differ between patients and controls. Concerning IL-1β, CSF concentrations in RA patients were higher than in serum, indicating local production in the CNS, and there was a positive correlation between CSF IL-1β and fatigue assessments. Next, spinal inflammation in experimental arthritis was investigated. A marked increase of IL-1β, IL-18, and tumor necrosis factor, but not IL-6 mRNA production, in the spinal cord was observed, coinciding with increased arthritis scores in the KBxN serum transfer model. These data provide evidence that peripheral inflammation such as arthritis is associated with an immunological activation in the CNS in both humans and mice, suggesting a possible therapeutic target for centrally affecting conditions as fatigue in chronic inflammatory diseases, for which to date there are no specific treatments.

Systemic inflammation sensitizes the neonatal brain to excitotoxicity through a pro-/anti-inflammatory imbalance: Key role of TNFα pathway and protection by etanercept

Systemic inflammation sensitizes the perinatal brain to an ischemic/excitotoxic insult but the mechanisms are poorly understood. We hypothesized that the mechanisms involve an imbalance between pro- and anti-inflammatory factors. A well characterized mouse model where a systemic injection of IL-1beta during the first five postnatal days (inflammatory insult) is combined with an intracerebral injection of the glutamatergic analogue ibotenate (excitotoxic insult) at postnatal day 5 was used. Following the inflammatory insult alone, there was a transient induction of IL-1beta and TNFalpha, compared with controls measured by quantitative PCR, ELISA, and Western blot. Following the combined inflammatory and excitotoxic insult, there was an induction of IL-1beta, TNFalpha, and IL-6 but not of IL-10 and TNFR1, indicating an altered pro-/anti-inflammatory balance after IL-1beta sensitized lesion. We then tested the hypothesis that the TNFalpha pathway plays a key role in the sensitization and insult using TNFalpha blockade (etanercept) and TNFalpha(-/-) mice. Etanercept given before the insult did not affect brain damage, but genetic deletion of TNFalpha or TNFalpha blockade by etanercept given after the combined inflammatory and excitotoxic insult reduced brain damage by 50%. We suggest this protective effect was centrally mediated, since systemic TNFalpha administration in the presence of an intact blood-brain barrier did not aggravate the damage and etanercept almost abolished cerebral TNFalpha production. In summary, sensitization was, at least partly, mediated by an imbalance between pro- and anti-inflammatory cytokines. Cerebral TNFalpha played a key role in mediating brain damage after the combined inflammatory and excitatory insult.

High anti-collagen type-II antibody levels and induction of proinflammatory cytokines by anti-collagen antibody-containing immune complexes in vitro characterise a distinct rheumatoid arthritis phenotype associated with acute inflammation at the time of disease onset

Objective: To investigate whether the cytokine-inducing properties of surface-bound collagen type II (CII)-containing immune complexes (IC), which were reported earlier, have any clinical impact. Methods: Anti-CII serology was analysed in 274 patients with early rheumatoid arthritis (RA). Patients with increased levels of anti-CII were followed serially for 1–5 years with regard to anti-CII IC-induced levels of tumour necrosis factor (TNF)α, interleukin (IL)1β and IL8. Levels of antibodies and IC-induced cytokines were compared with clinical indices over 5 years of follow-up. Results: 5/100 healthy controls and 24/274 (8.8%) patients with RA exhibited increased levels (>29 arbitrary units (AU)/ml) of anti-native CII antibodies, a non-significant difference. 9/274 (3.3%) patients with RA and no controls comprised a discrete group with high anti-CII levels >450 AU/ml. These high anti-CII level sera were associated with induction of pro-inflammatory cytokines by anti-CII-containing IC formed in vitro. 8/9 patients with high baseline anti-CII levels exhibited a parallel decline in antibody levels, IC-induced cytokines, C reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Anti-CII-positive patients had significantly increased levels of CRP and ESR at baseline, but not later during the follow-up. Conclusions: Anti-native CII-positive patients with RA have a distinct clinical phenotype characterised by an early acute phase response that might be driven by anti-CII-containing IC in joint cartilage.

Cell Specific Synovial Expression of Nicotinic Alpha 7 Acetylcholine Receptor in Rheumatoid Arthritis and Psoriatic Arthritis

Neuroimmune interactions are known to influence several chronic inflammatory and rheumatic diseases, but the underlying mechanisms have been insufficiently elucidated. The cholinergic anti‐inflammatory pathway is characterized by neural regulation of systemic inflammation, mediated by the vagus nerve and specific cholinergic stimulation of the nicotinic α‐7 acetylcholine receptor (α7nAChR) on immune cells. Moreover, α7nAChR has been shown important for immune regulation also in the absence of nerves, but little is known about these mechanisms in chronic joint inflammation. The expression and localization of α7nAChR in synovial biopsies from patients with rheumatoid arthritis and psoriatic arthritis was investigated by immunohistochemistry using monoclonal antibody against α7nAChR. Surface staining of α7nAChR was observed in synovial tissue of all arthritis patients investigated and could also to a lesser extent be detected in the synovium of healthy individuals. α7nAChR positive cells were detected in mainly synovial lining cells and vessels. The α7nAChR positively stained cells were by double immunofluorescence identified as primarily macrophages and fibroblasts, with the majority of these cells expressing the receptor. These results indicate the importance of α7nAChR and cholinergic mechanisms in arthritis pathogenesis and implicate specific cholinergic modulation as a potential anti‐inflammatory therapeutic strategy in joint inflammation.

Evidence of different mediators of central inflammation in dysfunctional and inflammatory pain--interleukin-8 in fibromyalgia and interleukin-1 β in rheumatoid arthritis.

The purpose of this study was to relate central inflammation to autonomic activity (heart rate variability (HRV)) in patients with rheumatoid arthritis (RA) and fibromyalgia (FM). RA patients had reduced parasympathetic activity and FM patients had increased sympathetic activity compared to healthy controls. Comparisons between RA and FM showed higher cerebrospinal fluid (CSF) interleukin (IL)-1β inversely correlated to parasympathetic activity in RA. The FM patients had higher concentrations of CSF IL-8, IL-1Ra, IL-4 and IL-10, but none of these cytokines correlated with HRV. In conclusion, we found different profiles of central cytokines, i.e., elevated IL-1β in inflammatory pain (RA) and elevated IL-8 in dysfunctional pain (FM).