Yuhui Li

Low-dose interleukin-2 treatment selectively modulates CD4 + T cell subsets in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a potentially life-threatening autoimmune disease characterized by altered balance of activity between effector and regulatory CD4+ T cells. The homeostasis of CD4+ T cell subsets is regulated by interleukin (IL)-2, and reduced production of IL-2 by T cells is observed in individuals with SLE. Here we report that treatment with low-dose recombinant human IL-2 selectively modulated the abundance of regulatory T (Treg) cells, follicular helper T (TFH) cells and IL-17-producing helper T (TH17) cells, but not TH1 or TH2 cells, accompanied by marked reductions of disease activity in patients with SLE.

Elevated Serum Interleukin 33 Is Associated with Autoantibody Production in Patients with Rheumatoid Arthritis

Objective. Interleukin 33 (IL-33) is a novel cytokine involved in joint inflammation in animal models. We analyzed the expression of IL-33 in the serum and synovial fluid of patients with rheumatoid arthritis (RA) and investigated its possible pathophysiological importance. Methods. The concentration of IL-33 was measured by ELISA in the serum of 223 patients with RA and 159 controls. Anticyclic citrullinated peptide, rheumatoid factor (RF)-IgA, and RF-IgG were tested by ELISA. Antikeratin antibody and antiperinuclear factor were tested by indirect immunofluorescence assay. Erythrocyte sedimentation rate, C-reactive protein, and immunoglobulins were measured by standard laboratory techniques. The association of IL-33 level with clinical and serologic features of RA was analyzed. We tested the change of IL-33 level following tumor necrosis factor (TNF-α) blockade therapy in 40 patients with RA. Results. In contrast to almost no detectable IL-33 in osteoarthritis and healthy serum, IL-33 could be detected in 94 out of the 223 RA cases (42.2%). Serum IL-33 concentration was significantly higher in patients with RA than in control groups. The level of serum IL-33 decreased after anti-TNF treatment. The level of serum IL-33 was correlated with the production of IgM and RA-related autoantibodies including RF and anticitrullinated protein antibodies. However, no correlation was found between IL-33 concentration and acute-phase inflammation reactant or the score of the Disease Activity Index, suggesting a complex or indirect character of the link between IL-33 and the inflammation in RA. Conclusion. The level of IL-33 is abnormally elevated in RA serum. The elevation of serum IL-33 was at least partly attributed to excessive TNF-α in RA. IL-33 might be involved in the regulation of autoantibody production in RA.

Identification of Potential Serum Biomarkers for Rheumatoid Arthritis by High-Resolution Quantitative Proteomic Analysis

The aim of this study was to find serum biomarkers of rheumatoid arthritis (RA) by high-resolution proteomic analysis. Low-abundance proteins from pooling serum sample of early RA patients and healthy controls were enriched using ProteoMiner™ enrichment kits. The enriched proteins were separated on SDS-PAGE, digested by trypsin, labeled with tandem mass tag (TMT) reagents, and desalted by C18 stage tip column. Then, the labeled peptides were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with nano-LC combined with Orbitrap Q Exactive mass spectrometer, and experiments were carried out three times using different specimens, and differentially expressed proteins were screened by intensity ratios of identified peptides. Enzyme-linked immunosorbent assays (ELISAs) were performed to confirm differentially expressed proteins. Twenty-six proteins were found differentially expressed in RA serum by high-resolution proteomic analysis. Among them, levels of thrombospondin-1, ficolin-2, isoform 10 of fibronectin, and apolipoprotein E were higher in RA patients than in healthy controls (RA/healthy control (HC)u2009≥u20091.5, pu2009<u20090.05), while levels of angiotensinogen, paraoxonase/arylesterase 1, isoform E of proteoglycan 4, and plasminogen were significantly lower (RA/HCu2009≤u20090.67, pu2009<u20090.05). Further study by ELISA showed a higher level of ficolin-2 in the serum of RA patients compared to healthy controls; the level of ficolin-2 was found to be positively correlated with swollen joint counts (SJCs), disease activity score (DAS28), rheumatoid factor, and IgM in RA patients and with DAS28 and IgM in early RA patients through statistical analysis. The results of this study suggest that ficolin-2, as a newly screened biomarker by high-resolution quantitative proteomic analysis, offers the potentiality to become a diagnostic or disease evaluation tool in RA.

A Cytomegalovirus Peptide-Specific Antibody Alters Natural Killer Cell Homeostasis and Is Shared in Several Autoimmune Diseases

Human cytomegalovirus (hCMV), a ubiquitous beta-herpesvirus, has been associated with several autoimmune diseases. However, the direct role of hCMV in inducing autoimmune disorders remains unclear. Here we report the identification of an autoantibody that recognizes a group of peptides with a conserved motif matching the Pp150 protein of hCMV (anti-Pp150) and is shared among patients with various autoimmune diseases. Anti-Pp150 also recognizes the single-pass membrane protein CIP2A and induces the death of CD56(bright) NK cells, a natural killer cell subset whose expansion is correlated with autoimmune disease. Consistent with this finding, the percentage of circulating CD56(bright) NK cells is reduced in patients with several autoimmune diseases and negatively correlates with anti-Pp150 concentration. CD56(bright) NK cell death occurs via both antibody- and complement-dependent cytotoxicity. Our findings reveal that a shared hCMV-induced autoantibody is involved in the decrease of CD56(bright) NK cells and may thus contribute to the onset of autoimmune disorders.

GITRL is associated with increased autoantibody production in patients with rheumatoid arthritis.

The study aimed to determine the serum level of glucocorticoid-induced tumor necrosis factor receptor family-related protein ligand (GITRL) in patients with rheumatoid arthritis (RA) and investigate its clinical significance. GITRL levels were measured by enzyme-linked immunosorbent assay (ELISA) in 88 RA patients, 20 osteoarthritis (OA) patients, and 20 healthy controls (HCs). Anti-cyclic citrullinated peptide (anti-CCP) antibodies and rheumatoid factor immunoglobulin G (RF-IgG) were also tested by ELISA. RF-IgM, anti-keratin antibody (AKA), and anti-perinuclear factor (APF) antibodies and the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and immunoglobulins were measured by standard laboratory techniques. The disease activity was evaluated by the 28-joint count Disease Activity Score (DAS28). GITRL concentrations were significantly elevated in both serum and synovial fluid (SF) of RA patients. GITRL levels in RA sera were significantly higher than those in matched SFs. Positive correlations were found between serum GITRL levels and inflammation parameters or autoantibody production. GITRL levels are significantly elevated in RA serum and SF and are positively correlated with autoantibody production in RA, suggesting a role of GITRL in the development of RA.

Establishment of a decision tree model for diagnosis of early rheumatoid arthritis by proteomic fingerprinting.

The objective of this study was to identify proteomic biomarkers specific for rheumatoid arthritis (RA) by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) in combination with weak cationic exchange (WCX) magnetic beads.

Establishment of a novel diagnostic model for Sjögren's syndrome by proteomic fingerprinting.

Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disease that lacks sensitive and specific diagnostic methods. The aim of this study was to identify potential biomarkers specific for pSS and to establish a diagnostic model. Serum samples from patients with pSS, disease controls (DC, patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA)), and healthy controls (HC)) were randomly divided into a training set (35 pSS, 50xa0DC, and 26 HC) and a testing set (25 pSS, 50xa0DC, and 25 HC). Weak cationic exchange (WCX) magnetic beads were used to differentially capture serum proteins prior to proteomic analysis. Proteomic mass spectra were generated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). One hundred differential M/Z peaks associated with pSS were identified, and the m/z peaks at 8,133.85, 11,972.8, 2,220.81, and 4,837.66 were used to establish a diagnostic model for pSS. This diagnostic model was able to distinguish pSS from non-pSS controls with a sensitivity of 77.1xa0% and a specificity of 85.5xa0%, and its efficacy was confirmed in our blinded testing set with good sensitivity and specificity of 95.5 and 88xa0%, respectively. The results indicated that the proteomic fingerprinting model was effective in the diagnosis of pSS.

Circulating immune complexome analysis identified anti-tubulin-α-1c as an inflammation associated autoantibody with promising diagnostic value for Behcet’s Disease

Background Behcet’s disease (BD) is a chronic, multisystem-involved vasculitis and its pathogenesis remains elusive. No specific serological markers for BD diagnosis have been established. Identification of novel diagnostic biomarkers will be helpful in timely diagnostic and treatment for Behcet’s disease. Objective To screen novel autoantigens or autoantibodies with potential diagnostic value in circulating immune complexes (CICs) from BD patients. Methods A proteomic strategy for immune complexome analysis was developed, in which CICs were separated from serum sample of 10 BD patients and 10 healthy controls and then subjected to Orbitrap mass spectrometry for autoantigen profiling. Anti-tubulin-α-1c antibody levels were further determined by enzyme-linked immunosorbent assay (ELISA) in sera of patients with BD, systemic lupus erythematosus (SLE), recurrent aphthous ulcers (RAU), ANCA associated systemic vasculitis (AASV), Takayasus arteritis (TA) and 59 healthy controls. Result A total of 17 potential antigens were identified in CICs from BD patients, but not in HC. The autoantibody to one of the identified antigens, tubulin-α-1c, was significantly increased in BD patients compared with that in healthy and disease controls. The sensitivity and specificity of tubulin-α-1c antibody in the diagnosis of BD in this study were 61.36% and 88.4%, respectively. Further analysis demonstrated that anti-tubulin-α-1c was associated with complications of deep venous thrombosis and erythema nodosum in BD. The levels of anti-tubulin-α-1c were also significantly correlated with the BD inflammation and disease activity markers ESR, CRP and BVAS. Conclusion Anti-tubulin-α-1c antibody is a promising biomarker in diagnosis and severity evaluation of BD and in indicating the risk of deep venous thrombosis and erythema nodosum. The immune complexome analysis by proteomic CIC autoantigen screening is a feasible way of identifying novel biomarkers in BD.

Identification of a novel autoantibody against self-vimentin specific in secondary Sjögren’s syndrome

BackgroundSjögren’s syndrome (SS) is a primary autoimmune disease (pSS) or secondarily associated with other autoimmune diseases (sSS). The mechanisms underlying immune dysregulation in this syndrome remain unknown, and clinically it is difficult to diagnose owing to a lack of specific biomarkers.MethodsWe extracted immunoglobulins (Igs) from the sera of patients with sSS associated with rheumatoid arthritis (RA) and used them to screen a phage display library of peptides with random sequences.ResultsOur results show that an sSS-specific peptide, designated 3S-P, was recognized by sera of 68.2% (60 of 88) patients with sSS, 66.2% of patients with RA-sSS, and 76.5% of patients with systemic lupus erythematosus (SLE)-sSS. The anti-3S-P antibody was scarcely found in patients with pSS (1.8%), RA (1.3%), SLE (4.2%), ankylosing spondylitis (0%), and gout (3.3%), as well as in healthy donors (2%). The 3S-P-binding Igs (antibodies) were used to identify antigens from salivary glands and synovial tissues from patients with sSS. A putative target autoantigen expressed in the synovium and salivary gland recognized by anti-3S-P antibody was identified as self-vimentin.ConclusionsThis novel autoantibody is highly specific in the diagnosis of sSS, and the underlying molecular mechanism of the disease might be epitope spreading involved with vimentin.