Cytometry by time of flight identifies distinct signatures in patients with systemic sclerosis,systemic lupus erythematosus and Sjögrens syndrome

Systemic sclerosis (SSc), systemic lupus erythematosus (SLE) and primary Sjögrens syndrome (pSS) are clinically distinct systemic autoimmune diseases (SADs) that share molecular pathways. We quantified the frequency of circulating immune-cells in 169 patients with these SADs and 44 healty controls (HC) using mass-cytometry and assessed the diagnostic value of these results. Alterations in the frequency of immune-cell subsets were present in all SADs compared to HC. Most alterations, including a decrease of CD56^hi NK-cells in SSc and IgM⁺ Bcells in pSS, were disease specific; only a reduced frequency of plasmacytoid dendritic cells was common between all SADs Strikingly, hierarchical clustering of SSc patients identified 4 clusters associated with different clinical phenotypes, and 9 of the 12 cell subset-alterations in SSc were also present during the preclinical-phase of the disease. Additionally, we found a strong association between the use of prednisone and alterations in B-cell subsets. Although differences in immune-cell frequencies between these SADs are apparent, the discriminative value thereof is too low for diagnostic purposes. Within each disease, mass cytometry analyses revealed distinct patterns between endophenotypes. Given the lack of tools enabling early diagnosis of SSc, our results justify further research into the value of cellular phenotyping as a diagnostic aid.     

Rheumatoid Factors: Host Resistance or Autoimmunity?

Rheumatoid factors (RFs), autoantibodies that bind to the Fc portion of IgG, are important in the immune response. RF-committed B-cells exist in the circulating lymphocyte pool in a high frequency (approximately 1-2 %) in normal individuals and in patients with pathological conditions associated with the sustained levels of circulating RF, such as rheumatoid arthritis (RA), Sjogren's syndrome (SS), and mixed cryoglobulinemia, associated with hepatitis C virus infection. RFs are induced by many infectious entities (viruses, bacteria, parasites) as a consequence of a secondary immune response to the pathogen, but usually the response is transient. It is likely that RFs play an important role in the host's defense against infection, both at the cellular level, where the RF B-cell can be an antigen presenting cell which can promote the antipathogen response, and at the humoral level, where RFs can contribute to the mopping up of the IgG antipathogen antibodies by contributing to immune complex formation and clearance. There has been much research on RFs in chronic pathological conditions, and the literature pertaining to their origin, structure, binding specificities, and possible roles in disease are discussed. The importance of the host defense, sometimes at the expense of an autoimmune response, is a balance that needs to be considered in light of a possible outcome of health or disease.     

Detection of human and murine common idiotypes of DNA antibodies in tissues and sera of patients with autoimmune diseases.

The expression in tissue and serum of a panel of murine and human common DNA antibody idiotypes (Ids) (BEG 2, PR 4, F-423, I-402, II-28, IV-228, V-88) has been investigated. The murine V-88 Id was detected in eight out of 10 and the human BEG 2 Id in five out of 10 labial biopsies from patients with Sjögren''s syndrome. The murine F-423, I-402 and IV-228 Ids were identified in one out of 10 biopsies. In each case the pattern of staining was similar with staining of the acinar basement membrane and a cell population. Using double-labelling immunohistochemistry this cell population were identified as plasma cells. No staining was seen in four normal labial biopsies. The V-88 Id was detected on the epithelial aspect of the thickened basement membrane in three out of nine renal biopsies from patients with systemic lupus erythematosus (SLE). None of the other Ids (BEG 2, PR4, IV-228, F-423 or I-402) could be detected in renal tissue. None of the Ids were found in skin biopsies from SLE patients. Id V-88 may, like the 16/6 Id to which it is phenotypically related, play a role in the pathogenesis of renal lesions in SLE. The BEG 2 Id could be detected in the serum of patients with rheumatoid arthritis (RA) and active untreated tuberculosis. Ids II-28, V-88 and I-402 were elevated in serum from patients with Sjögren''s syndrome and II-28 Id in serum from patients with myositis and RA. None of the Ids were elevated in serum from patients with SLE. Apart from the BEG 2 Id, none of the Ids were elevated in serum from patients with tuberculosis or Gram-negative infections. The presence of murine Ids in human tissue and serum suggests that they are cross-species idiotypes and have been conserved through evolution.     

Endoplasmic reticulum stress in autoimmune diseases

If the body's immune system is disordered and begins to attack “self” and therefore, its own tissues this is considered to be an autoimmune pathology. The specific mechanisms vary between the different diseases and have not always been elucidated but chronic, non-resolving inflammation is a common theme in the pathogenesis of autoimmune diseases. Interestingly, it has been shown that development and occurrence of various inflammatory responses are closely correlated to endoplasmic reticulum stress. Therefore, this review discusses the current progress of research about the relationship between autoimmune diseases and endoplasmic reticulum stress, specifically the unfolded protein response (UPR).     

Chronic granulomatous disease: complications and management

Autoimmune diseases are complex and enigmatic, and have presented particular challenges to researchers seeking to define their etiology and explain progression. Previous studies have implicated epigenetic influences in the development of autoimmunity. Epigenetics describes changes in gene expression related to environmental influences without alterations in the underlying genomic sequence, generally classified into three main groups: cytosine genomic DNA methylation, modification of various sidechain positions of histone proteins and noncoding RNAs feedback. The purpose of this article is to review the most relevant literature describing alterations of epigenetic marks in the development and progression of four common autoimmune diseases: systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and Sjögren’s syndrome. The contribution of DNA methylation, histone modification and noncoding RNA for each of these disorders is discussed, including examples both of candidate gene studies and larger epigenomics surveys, and in various tissue types important for the pathogenesis of each. The future of the field is speculated briefly, as is the possibility of therapeutic interventions targeting the epigenome.     

The microbiome in autoimmune diseases

The microbiome is represented by microorganisms which live in a symbiotic way with the mammalian. Microorganisms have the ability to influence different physiological aspects such as the immune system, metabolism and behaviour. In recent years, several studies have highlighted the role of the microbiome in the pathogenesis of autoimmune diseases. Notably, in systemic lupus erythematosus an alteration of the intestinal flora (lower Firmicutes/Bacteroidetes ratio) has been described. Conversely, changes to the gut commensal and periodontal disease have been proposed as important factors in the pathogenesis of rheumatoid arthritis. At the same time, other autoimmune diseases (i.e. systemic sclerosis, Sjögren’s syndrome and anti-phospholipid syndrome) also share modifications of the microbiome in the intestinal tract and oral flora. Herein, we describe the role of the microbiome in the maintenance homeostasis of the immune system and then the alterations of the microorganisms that occur in systemic autoimmune diseases. Finally, we will consider the use of probiotics and faecal transplantation as novel therapeutic targets.     

Infection and autoimmunity in Sjogren's syndrome: A clinical study and comprehensive review

Sjögren's syndrome (SS) is an autoimmune disease characterized primarily by lymphocytic infiltration of the exocrine glands, and autoantibody production. Multiple environmental factors affecting an individual with a genetic susceptibility may trigger the development of SS. Herein, we aimed to evaluate links between the different pebbles in the mosaic of SS. Demographic, clinical data and blood samples were gathered from 82 consecutive patients with SS, and 139 healthy controls. Samples were analyzed for infectious serology and auto-antibodies as well as for relevant genetic mutations (TAP genes) and cytokines levels. An immune response (IgG) against Epstein–Barr virus (EBV) early antigen (EA) was positively associated with SS (OR 4; 95% CI: 1.82–8.83, p = 0.001) while a protective effect of IgG anti-cytomegalovirus (CMV) was observed (OR 0.3; 95%CI: 0.16–0.74, p = 0.009). Anti-Ro/SSA, anti-LA/SSB, anti-nuclear, anti-gliadin, anti-TTG-IgG and anti-RNP antibodies were statistically more prevalent among SS patients than controls. Notably, the presence of anti-Ro/SSA and anti La/SSB correlated with anti-EBVEA IgG (OR 3.1; 95%CI: 1.08–8.74) and (OR 3.9; 95%CI: 1.37–10.96) respectively. Autoantibodies, cytokines and several genetic markers correlated with clinical manifestation of SS. Our data suggest that infectious agents may play both a causative and protective role in the pathogenesis of SS. Moreover certain autoantibodies, cytokines and specific TAP alleles correlate with clinical manifestations of SS, and may enable better prediction and/or directed therapy once confirmed in future studies.     

Recent advances of exosomes in immune modulation and autoimmune diseases

Exosomes are small membrane-bound vesicles (30-100?nm) that are secreted by different types of cells and they have been well documented to resemble saucers or flattened spheres under the electron microscope. Recently, evidence indicates that exosomes play important roles in the immune modulation and are associated with the immune pathogenesis of autoimmune diseases, including rheumatoid arthritis (RA), Sjogren’s syndrome (SS) and systemic lupus erythematosus (SLE). In this review, we will summarize current research advances of exosomes in immunoregulation, pathogenesis, diagnosis and therapeutics of autoimmune diseases.     

mTORC1-GLUT1-mediated glucose metabolism drives hyperactivation of B cells in primary Sjogren's syndrome

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease characterized by B cell hyperactivation and hypergrammaglobulinemia. Currently, the role of metabolic pathways in the B cells of pSS patients is poorly defined. Here, we showed that upon cytosine phosphate-guanine (CpG)/sCD40L/IL-4 stimulation, B cells proportionally increased glycolysis and oxygen consumption, and compared with B cells from healthy controls (HCs), B cells from pSS patients exhibited higher glycolysis capacity and maximal oxidative respiration (OXPHOS). We also found that glucose transporter 1 (GLUT1) expression in B cells from pSS patients was significantly higher than that in B cells from HCs. Treatment with 2-deoxy-d -glucose (2-DG) inhibited the activation of B cells in pSS patients. Both 2-DG and Metformin inhibited the proliferation, formation of plasma/plasmablasts and decreased the IgG and IgM levels in the supernatants of B cells from pSS patients. Furthermore, inhibition of mTORC1 by rapamycin had an effect similar to that of 2-DG, suppressing B cell activation, proliferation and antibody production. Taken together, we demonstrated that B cells from pSS patients are more metabolically active than those from HCs and suggested that the mTORC1-GLUT1 glycolysis pathways were the major drivers of B cell hyperactivation and autoantibody production in pSS patients.     

Accelerated atherosclerosis in systemic lupus erythematosus and other connective tissue diseases

Connective tissue diseases are associated with increased morbidity and mortality related to a higher rate of cardiovascular events and higher prevalence of subclinical atherosclerosis. Atherosclerosis is now considered a multifactorial process where autoimmunity and chronic inflammation play an important pathogenic role. In systemic autoimmune rheumatic diseases in general, and in systemic lupus erythematosus in particular, atherosclerosis cannot be explained by traditional cardiovascular risk factors alone. Cellular and humoral mechanisms, together with specific factors associated with the disease itself and/or its treatments, have been advocated to explain the acceleration of arterial wall organic damage in these patients. Endothelial dysfunction, carotid intima-media thickness and plaque evaluations provide accurate detection of atherosclerotic process at a preclinical stage, before appearance of clinical disease, allowing preventive measure introduction with the aim to modify the cardiovascular risk in subjects with systemic autoimmune rheumatic diseases.     

Anti-cyclic citrullinated peptide antibodies and joint involvement in Behçet's disease

Purpose

We aimed to determine the prevalence of anti-cyclic citrullinated peptide (anti-CCP) antibodies in a large group of Korean patients with Behçet''s disease (BD), with and without joint involvement, and to compare these findings with the prevalences of anti-CCP antibodies in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).

Materials and Methods

We tested 189 patients with BD, 105 with RA, and 36 with SLE for anti-CCP antibodies and IgM rheumatoid factor in serum. We reviewed the medical records of patients with BD to investigate their personal and clinical characteristics as well as their laboratory test results.

Results

Anti-CCP antibodies were detected in seven of the 189 BD patients (3.7%), at a mean titer of 30.6±44.4 U/mL, in 86 of the 105 RA patients (81.9%) with a mean titer of 198.8±205.7 U/mL, and in nine of the 36 SLE patients (25%) with a mean titer of 180.4±113.9 U/mL. One of the seven anti-CCP-positive BD patients fulfilled the diagnostic criteria for both BD and RA. Five of the seven anti-CCP-positive BD patients (71.4%) had polyarticular joint involvement, and the other two patients (28.6%) had oligoarticular involvement.

Conclusion

We determined the prevalence of anti-CCP antibodies in a large group of Korean BD patients with and without joint involvement. Negative anti-CCP test in patients with BD may help to differentiate BD from RA and SLE, all of which present with similar clinical features.     

Interstitial lung disease in systemic autoimmune rheumatic diseases: a comprehensive review

Background: Interstitial lung diseases (ILDs) are among the most serious complications associated with systemic rheumatic diseases, and lead to significant morbidity and mortality; they may also be the first manifestation of connective tissue diseases (CTDs). The aim of this narrative review is to summarise the data concerning the pathogenesis of CTD/ILD and its distinguishing features in different rheumatic diseseas.

Areas covered: The pathogenesis, clinical aspects and treatment of ILD associated with rheumatic systemic diseases and CTDs were reviewed by searching the PubMed, Medline, and Cochrane Library databases for papers published between 1995 and February 2017 using combinations of words or terms. Articles not written in English were excluded.

Expert commentary: The management of CTD–ILD is challenging because of the lack of robust data regarding the treatments used, the heterogeneity of the diseases themselves, and the scarcity of well-defined outcome measures. Treatment decisions are often made clinically on the basis of functional, radiographic progression, and exacerbating factors such as age and the burden of comorbidities. Given the complexities of diagnosis and the paucity of treatment trials, the management of CTD patients with ILD requires multidisciplinary collaboration between rheumatologists and pulmonologists in CTD-ILD clinics.     

A comprehensive investigation on the distribution of circulating follicular T helper cells and B cell subsets in primary Sjögren's syndrome and systemic lupus erythematosus

Follicular T helper (Tfh) cells have a crucial role in regulating immune responses within secondary lymphoid follicles by directing B cell differentiation towards memory B cells and plasma cells. Because abnormal humoral responses are key features in both primary Sjögren's syndrome (pSS) and systemic lupus erythematosus (SLE), the aim of this study was to profile the pathological connection between peripheral Tfh cells and B cells in the two diseases. Twenty‐five pSS patients, 25 SLE patients and 21 healthy controls were enrolled into the study. We determined the ratio of circulating Tfh‐like cells, their interleukin (IL)‐21 production and different B cell subsets by flow cytometry. We observed higher percentages of naive B cells in both diseases, while non‐switched and switched memory B cells showed decreased frequencies. The proportions of double‐negative B cells and plasmablasts were elevated in SLE and decreased in pSS. The percentages of transitional B cells and mature‐naive B cells were higher in SLE. Patients with more severe disease course had an elevated ratio of T_FH‐like cells and increased IL‐21 production. Moreover, expansion of Tfh‐like cells correlated positively with parameters related to antibody secretion, including serum immunoglobulin (Ig)G, immune complexes (ICs) and autoantibodies. Correlation analysis between Tfh‐like cells and certain B cell subsets revealed possible defects during B cell selection. In conclusion, our observations on the profound expansion of circulating Tfh‐like cells and their IL‐21 production, along with the characteristic aberrant peripheral B cell distribution in both pSS and SLE, indicate the prominent role of Tfh cell in the regulation of B cell selection.     

Calreticulin binds preferentially with B cell linear epitopes of Ro60 kD autoantigen,enhancing recognition by anti-Ro60 kD autoantibodies

Calreticulin is a molecular chaperone to newly synthesized polypeptides. Previous studies suggested that calreticulin is probably a protein member of the Ro/La RNP complex. The aims of this study were (a) to investigate whether linear B cell epitopes of the Ro/La RNP complex are bound to calreticulin and (b) if the complex peptide–calreticulin is recognized specifically by anti‐Ro autoantibodies. Calreticulin was isolated from either human or pig spleen using a multi‐step purification method and found to interact preferentially with biotinylated peptides derived from the sequence of the Ro60 kD 175–184aa(10p) and 216–232aa(17p). The interaction of the peptide–calreticulin complex was favoured by the combination of heat treatment, divalent cations and ATP. La/SSB epitopes did not react with calreticulin. Peptides corresponding to La/SSB epitopes as well as the common epitope of Sm did not interact with calreticulin. Thirty‐eight anti‐Ro60 KD positive and 23 anti‐Ro60 kD negative sera of patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) were tested. All anti‐Ro60 kD positive sera bound the complex calreticulin‐17p, while 95% of the same sera had activity against the complex calreticulin ? 10p. Tested individually, calreticulin, pep10p and pep17p presented very low reactivity (8%, 11% and 29%, respectively) against anti‐Ro60 kD positive sera. Anti‐Ro60 KD negative sera did not exhibit significant reactivity either with calreticulin, 10ρ and 17ρ or with the complexes calreticulin ? 10p and calreticulin‐17p (<5%). These results suggest that calreticulin can induce conformation‐dependent recognition of the Ro60 kD epitopes, leading eventually to their recognition by autoantibodies. This is the first time that such a relationship is shown between a chaperone protein and fragments of an intracellular autoantigen. This work also provides insights into the understanding of mechanisms for autoantibody production. Furthermore, this association can be proved useful for the development of new sensitive assays for autoantibody detection.     

Free light chains and autoimmunity

The study of free light chains (FLCs) has grown as area of enormous interest for many clinicians with the aim of disclosing the exact biological role and potential use of FLCs in the clinical routine. Moreover, the attention given to immunological functions of FLCs has sparked a new light into their pathogenic contribution in different chronic autoimmune-based inflammatory diseases. The release of intracellular antigens following cell death or ineffective clearance of apoptotic debris, modification of self-antigens, and molecular mimicry may trigger the production of immunoglobulins after activation and polyclonal expansion of B cells, by which FLCs are released. The discovery of polyclonal FLCs as potential biomarkers started with the observation of their increased concentrations in a variety of biological fluids related to patients with autoimmune diseases. This review deals with the use of polyclonal FLCs for identifying severity and monitoring outcome after treatment in some autoimmune diseases, namely systemic lupus erythematosus, myasthenia gravis, systemic sclerosis, rheumatoid arthritis and Sjögren's syndrome, as supported by the fact that levels of FLCs correlate with both B cell activation markers and other specific markers of disease activity. In a near future, following the evidence shown, FLCs might probably work as early prognostic markers of severity and also as indicators of response to treatment or early assessment of relapse in selected autoimmune diseases.     

Anti-Ro/SSA and La/SSB antibodies

The Ro/La system is considered as an heterogeneous antigenic complex, constituted by three different proteins (52?kDa Ro, 60?kDa Ro and La) and four small RNAs particles. Anti-Ro/SSA are the most prevalent specificity among many autoimmune diseases, such as systemic lupus erythematosus (SLE), SS/SLE overlap syndrome, subacute cutaneous LE (SCLE), neonatal lupus and primary biliary cirrhosis. In contrast, anti-La/SSB is more associated with Sjögren's syndrome (SS). The differences between 52?kDa, 60?kDa Ro and La could explain why different assays did not show equivalent performance in anti-Ro and anti-La autoantibodies detection. The RNA precipitation assay had the highest sensitivity and specificity, usually considered as the reference methods. CIE is considered the most reliable to detect anti-Ro/SSA antibodies in routine practice, performing better than immunoblotting (IB) and some ELISAs. It shows a high sensitivity (89%) and specificity (100%). ELISA is generally considered a safe, rapid, sensitive and specific tecnique. Therefore, its high sensitivity often corresponds to a very low clinical specificity and the assay can give false positive results. Therefore, it is very important to search anti-Ro and anti-La only in selected patients, using the assay with high specificity and good predictive value, in order to have clinically significant and true positive results.     

Fine specificity of autoantibodies to La/SSB: epitope mapping, and characterization

The B cell epitope mapping of La/SSB was performed using 20 mer synthetic peptides overlapping by eight amino acids covering the whole sequence of the protein. IgG, purified from sera of five patients with systemic lupus erythematosus (SLE) and four sera from patients with primary Sjögren's syndrome (pSS) were tested against the overlapping synthetic peptides. Peptides highly reactive with purified IgG were those spanning the regions 145–164, 289–308, 301–320 and 349–368 of the La protein. Determination of the minimum required length of the antigenic determinants disclosed the following epitopes:¹⁴⁷HKAFKGSI¹⁵⁴, ²⁹¹NGNLQLRNKEVT³⁰², ³⁰¹VTWEVLEGEVEKEALKKI³¹⁸ and ³⁴⁹GSGKGKVQFQGKKTKF³⁶⁴. Predicted features and molecular similarities of the defined epitopes were investigated using protein databases. The La epitope ¹⁴⁷HKAFKGSI¹⁵⁴ presented 83.3% similarity with the ¹³⁹HKGFKGVD¹⁴⁶ region of human myelin basic protein (MBP) and 72% similarity with the fragment YKNFKGTI of human DNA topoisomerase II. Peptides corresponding to these sequences cross-reacted with anti-La/SSB antibodies. Sixty-three sera with anti-La/SSB antibodies from patients with pSS or SLE, 35 sera without anti-La/SSB antibodies from patients with SS or SLE and 41 sera from age/sex-matched healthy blood donors were tested against biotinylated synthetic epitope analogues in order to determine their sensitivity and specificity for the detection of anti-La/SSB antibodies. Anti-La/SSB were detected with various frequencies ranging from 20% to epitope ¹⁴⁷HKAFKGSI¹⁵⁴ to 100% to epitope ³⁴⁹GSGKGKVQGKKTKF³⁶⁴. The overall sensitivity and specificity using all assays with the synthetic peptides were found to be 93.6% and 85.6%, respectively. In conclusion, antibodies to La/SSB constitute a heterogeneous population, directed against different linear B cell epitopes of the molecule. The epitope ¹⁴⁷HKAFKGSI¹⁵⁴ presents molecular similarity with fragments of two other autoantigens, i.e. human MBP and DNA topoisomerase II. Finally, synthetic epitope analogues exhibit high sensitivity and specificity for the detection of anti-La/SSB antibodies.     

Heterogeneity of the Ro/SSA antigen and autoanti-Ro/SSA response: evidence of the four antigenically distinct forms.

Precipitating antibodies to the Ro/SSA antigen occur in the sera of 40% of patients with sytemic lupus erythematosus (SLE) and in 40–70% of the sera of patients with primary Sjögren's syndrome. Previous work has shown that lymphocyte extracts contain two Ro/SSA antigens with protein moieties of 60 kD and 52 kD and that erythrocyte haemolysate contain two analogous but antigenically distinct Ro/SSA molecules of 60 kD and 54 kD. Frequency analysis of the various specificities in 43 sera with precipitating anti-Ro/SSA and studies with affinity-eluted antibodies suggest that the lymphocyte 60 kD and erythrocyte 60 kD Ro/SSA molecules are related as are the lymphocyte 52 kD and erythrocyte 54 kD Ro/SSA proteins. Anti-Ro/SSA sera when accompanied by other precipitins (anti-La/SSB and anti-U1RNP) react preferentially with certain Ro/SSA isoforms. Evidence is also presented for a 45 kD form of Ro/SSA. These data suggest that the antigenic heterogeneity of the Ro/SSA antigen is immunologically relevant and that there are two families of Ro/SSA antigens: one comprising of the two 60-kD proteins in the erythrocyte and lymphocyte and the other the erythrocyte 54 kD and lymphocyte 52 kD Ro/SSA proteins, respectively.     

Soluble CD23 levels are elevated in the serum of patients with primary Sjögren''s syndrome and systemic lupus erythematosus.

The low affinity IgE receptor Fc epsilon RII (CD23) is important in several aspects of T and B cell function. In this study serum levels of soluble CD23 (sCD23) were measured in three groups: 26 female patients with systemic lupus erythematosus (SLE), 21 females with primary Sjögren''s syndrome (pSS) and 25 normal healthy females. The concentration of sCD23 was determined using an enhanced chemiluminescent sandwich ELISA developed in this laboratory. Increased levels of sCD23 were observed in pSS and in SLE patients compared with controls (median 23.0 versus 8.6, P less than 0.0002 and 18.1 versus 8.6, P less than 0.002 respectively). While the median level of sCD23 was found to be higher in pSS than in SLE the difference was not statistically significant. Patients with SLE and pSS on glucocorticoid treatment had significantly lower levels of sCD23 than patients not on this treatment (median 28.9 versus 14.4, P less than 0.05). Amongst the control patients sCD23 was inexplicably lower in the female members relative to the males (median 8.5 versus 12.3, P less than 0.05). Although serum IgG and IgA levels were significantly elevated in pSS and SLE patients relative to controls there was no direct correlation between sCD23 and the serum levels of these immunoglobulins. We conclude that B cell hyperactivity which occurs in both pSS and SLE is associated with raised levels of sCD23.     

Anti‐centrosome antibodies: Prevalence and disease association in Chinese population

Anti‐centrosome antibodies are rare findings with undefined clinical significance in clinical research. We aimed at investigating the prevalence and clinical significance of anti‐centrosome antibodies in Chinese population. Testing results of total of 281,230 ANA‐positive sera were retrospectively obtained from West China Hospital Sichuan University in China between 2008 and 2017. We retrospectively collected and analysed the clinical and laboratory data of the patients with positive anti‐centrosome antibody. Of the 356 453 patients tested, 281 230 patients had positive antinuclear antibodies (ANAs, 78.9%), but only 78 patients with positive anti‐centrosome antibodies (0.022%), of which 74.4% are females. Diagnoses were established in 69 of 78 patients: 37 cases were autoimmune diseases, mainly including undifferentiated connective tissue diseases (UCTD, 9/37), rheumatoid arthritis (RA, 6/37), Sjögren's syndrome (SS, 5/37) and primary biliary cirrhosis (PBC, 5/37), and the remaining were other autoimmune conditions. The most frequent clinical symptoms of the anti–centrosome‐positive patients were arthralgia and eyes and mouth drying. Additionally, 86.7% of anti‐centrosome antibodies were not associated with other ANA profiles; however, when associated, the most frequent ANA was anti‐U1RNP. Anti‐centrosome antibodies are featured by a low prevalence and female gender predominance. They are correlated with some specific diseases, both autoimmune diseases, especially UCTD, RA, SS and PBC, and non‐autoimmune diseases, such as infection and cancer, which suggests that they might be potential supporting serological markers of these diseases.