Peter Szodoray

Association between circulating levels of the novel TNF family members APRIL and BAFF and lymphoid organization in primary Sjögren's syndrome.

B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are members of the tumour necrosis factor superfamily. We have examined circulating BAFF and APRIL in relation to serological deviations and lymphoid organization in the salivary glands of the chronic, autoimmune disorder Sjögren’s syndrome. Lymphoid organization in the shape of ectopic germinal centers were detected in 33 of 130 consecutive minor salivary gland biopsies and coincided with increased focus score and elevated levels of serum IgG. Follicular dendritic cell networks, proliferation of mononuclear cells and altered B/T cell ratio also separated the two subgroups. Serum levels of sBAFF and sAPRIL were increased in Sjögren’s syndrome compared to healthy blood donors, especially in anti-Ro/La+ patients. Though the differences could not be related to germinal center formation, positive correlations between serum levels of sBAFF and sAPRIL, focus score and IgG denotes their possible role in the disease progression of primary Sjögren’s syndrome.

The complex role of vitamin D in autoimmune diseases.

Vitamin D, besides having well‐known control functions of calcium and phosphorus metabolism, bone formation and mineralization, also has a role in the maintenance of immune‐homeostasis. The immune‐regulatory role of vitamin D affects both the innate and adaptive immune system contributing to the immune‐tolerance of self‐structures. Impaired vitamin D supply/regulation, amongst other factors, leads to the development of autoimmune processes in animal models of various autoimmune diseases. The administration of vitamin D in these animals leads to improvement of immune‐mediated symptoms. Moreover, in human autoimmune diseases, such as multiple sclerosis, or rheumatoid arthritis the pathogenic role of vitamin D has been described. The review aims at describing the complex immune‐regulatory role of vitamin D from the cellular level through autoimmune animal models and depicting the known contribution of vitamin D in the pathogenesis of human autoimmune diseases.

Circulating cytokines in primary sjögren's syndrome determined by a multiplex cytokine array system

Plasma cytokines play an important role in the pathogenesis of Sjögrens syndrome (SS) by initiating and perpetuating various cellular and humoural autoimmune processes. The aim of the present study was to describe a broad spectrum of T‐cell and B‐cell cytokines, growth factors, chemokines and molecules that could contribute to cell death in SS. A novel protein array system was utilized to measure simultaneously the levels of 25 plasma cytokines of patients with primary SS and healthy individuals. Furthermore, we correlated these plasma cytokine levels with potential laboratory and clinical parameters related to disease activity in SS. A subset of plasma cytokines [e.g. interleukin‐1β (IL‐1β), IL‐6, CXCL8 (IL‐8), IL‐12 p40, IL‐15, tumour necrosis factor‐α (TNF‐α), epidermal growth factor, CCL4 (MIP‐1β), CCL2 (MCP‐1), CCL11 (Eotaxin), CCL5 (RANTES), TNF‐RI and TNF‐RII] was found to significantly differ between patients and controls. Also, distinct populations of cytokines were found to differentiate between patients with normal versus elevated ESR or IgG levels and patients with the presence or absence of extra‐glandular manifestations (EGMs). Our results support the assumption that the multiplex cytokine array system can be successfully utilized in the diagnosis and disease management of SS. Furthermore, it may provide a powerful tool in the design of individualized anticytokine therapies.

Anti-citrullinated protein/peptide autoantibodies in association with genetic and environmental factors as indicators of disease outcome in rheumatoid arthritis.

Anti-citrullinated protein/peptide antibodies (ACPA) have recently emerged as sensitive and specific serological markers of rheumatoid arthritis (RA), providing superior alternative of the rheumatoid factor (RF) test in the laboratory diagnostics of RA. Citrullination is a post-translational modification of arginine by deimination, physiologically occurring during apoptosis, inflammation or keratinization. The presence of several citrullinated proteins has been demonstrated in the RA synovium. The identification of citrullinated epitopes as targets led to the development of the first and later second-generation anti-cyclic citrullinated peptide (anti-CCP) antibody assays. The anti-Sa antibody has been identified a decade ago; however, recent studies confirmed that anti-Sa is directed against citrullinated vimentin. The determination of ACPA may have important prognostic significance, since ACPA production can precede the onset of clinical RA symptoms by years. ACPA(+) individuals with early, undifferentiated arthritis may have higher risk to develop RA. ACPA has important prognostic role during the progression of RA and it has also been associated with pronounced radiographic progression. ACPA production has been associated with several genetic predisposing factors, including HLA-DRB1 and PTPN22 1858T alleles, as well as with environmental and lifestyle-related factors, primarily smoking and possibly, the use of oral contraceptives and excessive caffeine intake. Thus, the assessment of ACPA, in addition to clinical, radiographic and genetic outcome measures may be important to assess disease prognosis and aids to design effective, early therapeutic strategies.

Functional anergy in a subpopulation of naive B cells from healthy humans that express autoreactive immunoglobulin receptors

Self-reactive B cells not controlled by receptor editing or clonal deletion may become anergic. We report that fully mature human B cells negative for surface IgM and retaining only IgD are autoreactive and functionally attenuated (referred to as naive IgD+IgM− B cells [BND]). These BND cells typically make up 2.5% of B cells in the peripheral blood, have antibody variable region genes in germline (unmutated) configuration, and, by all current measures, are fully mature. Analysis of 95 recombinant antibodies expressed from the variable genes of single BND cells demonstrated that they are predominantly autoreactive, binding to HEp-2 cell antigens and DNA. Upon B cell receptor cross-linkage, BND cells have a reduced capacity to mobilize intracellular calcium or phosphorylate tyrosines, demonstrating that they are anergic. However, intense stimulation causes BND cells to fully respond, suggesting that these cells could be the precursors of autoantibody secreting plasma cells in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis. This is the first identification of a distinct mature human B cell subset that is naturally autoreactive and controlled by the tolerizing mechanism of functional anergy.

Vitamin D deficiency in undifferentiated connective tissue disease

IntroductionBoth experimental and clinical data provide evidence that vitamin D is one of those important environmental factors that can increase the prevalence of certain autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, insulin-dependent diabetes mellitus, and inflammatory bowel disease. The aim of the present study was to investigate the prevalence of vitamin D insufficiency in patients with undifferentiated connective tissue disease (UCTD).MethodsPlasma 25(OH)D3 levels in 161 UCTD patients were measured in both summer and winter periods. Autoantibody profiles (antinuclear antibody, anti-U1-ribonucleoprotein, anti-SSA, anti-SSB, anti-Jo1, anti-Scl70, anti-double-stranded DNA, anti-centromere, anti-cardiolipin, rheumatoid factor, and anti-cyclic citrullinated peptide) and clinical symptoms of the patients were assessed.ResultsPlasma levels of 25(OH)D3 in UCTD patients were significantly lower compared with controls in both summer and winter periods (UCTD summer: 33 ± 13.4 ng/mL versus control: 39.9 ± 11.7 ng/mL, P = 0.01; UCTD winter: 27.8 ± 12.48 ng/mL versus control: 37.8 ± 12.3 ng/mL, P = 0.0001). The presence of dermatological symptoms (photosensitivity, erythema, and chronic discoid rash) and pleuritis was associated with low levels of vitamin D. During the average follow-up period of 2.3 years, 35 out of 161 patients (21.7%) with UCTD further developed into well-established connective tissue disease (CTD). Patients who progressed into CTDs had lower vitamin D levels than those who remained in the UCTD stage (vitamin D levels: CTD: 14.7 ± 6.45 ng/mL versus UCTD: 33.0 ± 13.4 ng/mL, P = 0.0001).ConclusionsIn patients with UCTD, a seasonal variance in levels of 25(OH)D3 was identified and showed that these levels were significantly lower than in controls during the corresponding seasons. Our results suggest that vitamin D deficiency in UCTD patients may play a role in the subsequent progression into well-defined CTDs.

The BAFF/APRIL system in systemic autoimmune diseases with a special emphasis on Sjögren's syndrome.

Systemic autoimmune diseases, such as Sjögrens syndrome (SS), are characterized by a complex aetiology with multiple pathogenic factors. In SS, disturbed B‐cell biology and humoral immunity including B‐cell‐activating factor (BAFF)‐mediated processes have been described. Dysregulated BAFF expression has been described to lead to disease progression and perpetuation of humoral autoimmunity. Moreover, BAFF has been proposed to contribute to the development of B‐cell malignancies. In this review, we summarize the current knowledge on BAFF with regard to SS pathology and discuss special features such as germinal centre (GC) formation and lymphomagenesis. Locally, in SS salivary glands, the reduced level of apoptosis among BAFF‐expressing cells might lead to longer‐existing BAFF expression and thereby maintain signalling for tissue‐infiltrating B cells to proliferate and supposedly to become autoantibody‐producing plasma cells. We assume that prolonged BAFF signalization may contribute to GC formation and/or lymphoma development in the disease. Finally, we discuss possibilities of novel treatments targeting the BAFF‐system in SS.

Novel approaches to gene expression analysis of active polyarticular juvenile rheumatoid arthritis

Juvenile rheumatoid arthritis (JRA) has a complex, poorly characterized pathophysiology. Modeling of transcriptosome behavior in pathologic specimens using microarrays allows molecular dissection of complex autoimmune diseases. However, conventional analyses rely on identifying statistically significant differences in gene expression distributions between patients and controls. Since the principal aspects of disease pathophysiology vary significantly among patients, these analyses are biased. Genes with highly variable expression, those most likely to regulate and affect pathologic processes, are excluded from selection, as their distribution among healthy and affected individuals may overlap significantly. Here we describe a novel method for analyzing microarray data that assesses statistically significant changes in gene behavior at the population level. This method was applied to expression profiles of peripheral blood leukocytes from a group of children with polyarticular JRA and healthy control subjects. Results from this method are compared with those from a conventional analysis of differential gene expression and shown to identify discrete subsets of functionally related genes relevant to disease pathophysiology. These results reveal the complex action of the innate and adaptive immune responses in patients and specifically underscore the role of IFN-γ in disease pathophysiology. Discriminant function analysis of data from a cohort of patients treated with conventional therapy identified additional subsets of functionally related genes; the results may predict treatment outcomes. While data from only 9 patients and 12 healthy controls was used, this preliminary investigation of the inflammatory genomics of JRA illustrates the significant potential of utilizing complementary sets of bioinformatics tools to maximize the clinical relevance of microarray data from patients with autoimmune disease, even in small cohorts.

Attenuated Apoptosis of B Cell Activating Factor–Expressing Cells in Primary Sjögren’s Syndrome

B cell activating factor (BAFF) is known to be a powerful regulator of B-cell differentiation and proliferation. The aim of this study was to assess the incidence of apoptosis among BAFF-expressing cells in Sjögren’s syndrome (SS) salivary gland tissue. We performed double stainings of BAFF together with one of the markers, CD21, CD68, CD40, Fas, Bcl-2 or Bax, and monitored apoptosis among BAFF expressing cells by using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling method. A significantly lower level of apoptosis among the BAFF-expressing cells was detected in salivary glands from patients with SS compared with controls (p = 0.03). Furthermore, no difference in the coexpression of Fas or CD40 together with BAFF was detected between patients and controls. Coexpression of the pro apoptotic molecule Bax together with BAFF was nonsignificantly decreased in patients with SS compared with controls. Our results suggest that a reduced level of apoptosis among BAFF-expressing cells might lead to longer-existing BAFF expression within these cells and thereby maintain signaling for tissue-infiltrating B cells to proliferate and mature.

Comparative assessment of vascular function in autoimmune rheumatic diseases: considerations of prevention and treatment.

Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to increased cardio- and cerebrovascular disease risk. Traditional risk factors, as well as the role of systemic inflammation including cytokines, chemokines, proteases, autoantibodies, adhesion receptors and others have been implicated in the development of these vascular pathologies. The characteristics of vasculopathies may significantly differ depending on the underlying disease. While classical accelerated atherosclerosis has been associated with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or spondyloarthropathies (SpA), obliterative vasculopathy may rather be characteristic for systemic sclerosis (SSc) or mixed connective tissue disease (MCTD). Antiphospholipid antibodies have been implicated in vasculopathies underlying SLE, antiphospholipid syndrome (APS), RA and MCTD. There is also heterogeneity with respect to inflammatory risk factors. Cytokines, such as tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6) and immune complexes are primarily involved in arthritides, such as RA, SpA, as well as in SLE. On the other hand, autoantibodies including anti-oxLDL anti-cardiolipin and anti-β2GPI are rather involved in SLE- and APS-associated vasculopathies. Regarding the non-invasive assessment of vascular function, endothelial dysfunction, overt atherosclerosis and vascular stiffness may be indicated by brachial artery flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT) and aortic pulse-wave velocity (PWV), respectively. These abnormalities have been described in most inflammatory rheumatic diseases. While ccIMT and stiffness are relatively stable, FMD may be influenced by many confounding factors. In addition to traditional vasculoprotection, immunosuppressive agents including corticosteroids, traditional and biologic DMARDs may have significant vascular and metabolic effects. The official EULAR recommendations on the assessment and management of cardiovascular disease in arthritides have just been published, and similar recommendations in connective tissue diseases are to be developed soon.