Autoantibodies to nuclear valosin-containing protein-like protein: systemic sclerosis-specific antibodies revealed by in vitro human proteome.

OBJECTIVES: To identify and characterize undescribed systemic sclerosis (SSc)-specific autoantibodies targeting nucleolar antigens and to assess their clinical significance. METHODS: We conducted proteome-wide autoantibody screening (PWAS) against serum samples from SSc patients with nucleolar patterned anti-nuclear antibodies (NUC-ANAs) of specific antibodies (Abs) unknown, utilizing wet protein arrays fabricated from in vitro human proteome. Controls included SSc patients with already-known SSc-specific autoantibodies, patients with other connective tissue diseases, and healthy subjects. The selection of nucleolar antigens was performed by database search in the Human Protein Atlas. The Presence of autoantibodies was certified by immunoblots and immunoprecipitations. Indirect immunofluorescence assays on HEp-2 cells were also conducted. Clinical assessment was conducted by retrospective review of electric medical records. RESULTS: PWAS identified three candidate autoantibodies, including anti-nuclear valosin-containing protein-like (NVL) Ab. Additional measurements in disease controls revealed that only anti-NVL Abs are exclusively detected in SSc. Detection of anti-NVL Abs was reproduced by conventional assays such as immunoblotting and immunoprecipitation. Indirect immunofluorescence assays demonstrated homogeneous nucleolar patterns. Anti-NVL Ab-positive cases were characterized by significantly low prevalence of diffuse skin sclerosis and interstitial lung disease, compared with SSc cases with NUC-ANAs other than anti-NVL Abs, such as anti-U3-RNP and anti-Th/To Abs. CONCLUSION: Anti-NVL Ab is an SSc-specific autoantibody associated with a unique combination of clinical features, including limited skin sclerosis and lack of lung involvement.

Significance of anti-transcobalamin receptor antibodies in cutaneous arteritis revealed by proteome-wide autoantibody screening.

Cutaneous arteritis (CA) is a single-organ vasculitis that exclusively affects the small to medium-sized arteries of the skin. Diagnosis depends on a histological investigation with skin biopsy, which could be burdensome for both patients and clinicians. Moreover, the pathogenesis of CA remains unstudied, and treatment has not yet been established. Herein, we applied our proteome-wide autoantibody screening method to explore autoantibodies in the serum of CA patients. As a result, anti-transcobalamin receptor (TCblR) antibodies (Abs) were specifically detected in 24% of CA patients. Patients with positive anti-TCblR Abs were spared from peripheral neuropathy compared to those with negative anti-TCblR Abs, showing characteristics as CA confined to the skin. In addition, we revealed that anti-TCblR Abs trigger the autocrine loop of interleukin-6 mediated by tripartite motif-containing protein 21 in human endothelial cells and induce periarterial inflammation in murine skin. Furthermore, we demonstrated that methylcobalamin, a ligand of TCblR, ameliorates inflammation caused by anti-TCblR Abs both in vitro and in vivo. Collectively, our investigation unveils the pathologic significance of anti-TCblR Abs in CA and their potential as a diagnostic marker and a pathophysiology-oriented therapeutic target.

Serum C-X-C Chemokine Ligand 1 Levels in Patients with Systemic Sclerosis: Relationship of Clinical and Laboratory Observations to Anti-CD20 Monoclonal Antibody Administration.

Objectives: To determine whether C-X-C chemokine ligand 1 (CXCL1), which is a potent neutrophil chemoattractant and activator that plays important role in inflammation, is elevated in patients with systemic sclerosis (SSc) and whether it is associated with the clinical features and disease activity of patients with SSc. In addition, to determine whether the changes in serum CXCL1 levels before and after treatment correlate with changes in disease activity in SSc patients who received an anti-CD20 monoclonal antibody drug. Patients and method: We examined patient serum collected in the DesiReS trial, which was a double-blind, parallel-group, randomized, placebo-controlled, multicenter, phase II clinical trial. In the trial, patients were randomly allocated to the drug or placebo group and received 375 mg/m2 of an anti-CD20 antibody, rituximab, or placebo once a week for four weeks. We obtained serum samples from 47 patients administered at our hospital, including 3 males and 44 females, the median age of 48 years, range 27−71 years, with 42 diffuse cutaneous SSc and 5 with limited cutaneous SSc. Serum CXCL1 levels were measured using multiplex immunoassay in patient serum before and 24 weeks after administration and also in serum from 33 healthy controls. Results: Serum CXCL1 levels were significantly higher in SSc patients (mean 25.70 ng/mL; 95% confidence interval (CI) 18.35−33.05 ng/mL) than in the healthy controls (15.61 ng/mL; 95% CI 9.73−21.51 ng/mL). In addition, SSc patients with elevated CXCL1 levels had a significantly higher percentage of area occupied with interstitial shadows (p < 0.05), increased serum levels of surfactant protein (SP)-A (p < 0.05), SP-D (p < 0.05), Krebs von den Lungen-6 (p < 0.01), and C-reactive protein (p < 0.05) compared to those with normal levels. Furthermore, defining Δ as the value after rituximab administration minus the value before rituximab administration, baseline serum CXCL1 levels correlated with Δ percent predicted diffusing capacity for carbon monoxide (p < 0.01). In addition, ΔCXCL1 correlated with ΔSP-A (p < 0.05). Similarly, serum CXCL1 levels after rituximab administration correlated with percent predicted forced vital capacity (p < 0.05) and serum SP-D levels (p < 0.05) after rituximab. Conclusions: Our results suggest that serum CXCL1 is associated with the disease activity of SSc-ILD, and high serum CXCL1 levels are one of the predictors of improvement in SSc-ILD with rituximab.

Autoantibody Landscape Revealed by Wet Protein Array: Sum of Autoantibody Levels Reflects Disease Status.

Autoantibodies are found in various pathological conditions such as autoimmune diseases, infectious diseases, and malignant tumors. However their clinical implications have not yet been fully elucidated. Herein, we conducted proteome-wide autoantibody screening and quantification with wet protein arrays consisting of proteins synthesized from proteome-wide human cDNA library (HuPEX) maintaining their three-dimensional structure. A total of 565 autoantibodies were identified from the sera of three representative inflammatory disorders (systemic sclerosis, psoriasis, and cutaneous arteritis). Each autoantibody level either positively or negatively correlated with serum levels of C-reactive protein, the best-recognized indicator of inflammation. In particular, we discovered total levels of a subset of autoantibodies correlates with the severity of clinical symptoms. From the sera of malignant melanoma, 488 autoantibodies were detected. Notably, patients with metastases had increased overall autoantibody production compared to those with tumors limiting to the primary site. Collectively, proteome-wide screening of autoantibodies using the in vitro proteome can reveal the "autoantibody landscape" of human subjects and may provide novel clinical biomarkers.

Cutaneous methotrexate-related T-cell lymphoproliferative disorder with CD4, CD30, CD56, EBV-positive tumor cell infiltration: a case illustration and a brief review.

Methotrexate (MTX) is a commonly used anti-metabolite agent. Long-term MTX treatment can cause MTX-related lymphoproliferative disorder (MTX-LPD). T-cell LPDs comprise a small fraction of MTX-LPDs. Epstein-Barr virus (EBV)+ tumor cells are rarely detected in MTX-related T-cell LPDs (MTX T-LPDs). Therefore, there have been very few reports of EBV+ MTX T-LPD. We encountered a case of cutaneous MTX T-LPD with a unique cellular phenotype. The patient was a 71-year-old Japanese man with rheumatoid arthritis treated with MTX for 6 years. He was referred to our department with a 6-month history of red plaques and ulcerated lesions in both lower legs and a 2-week history of high fever and fatigue. Cutaneous specimens showed that medium-sized atypical lymphocytes were positive for CD3, CD4, CD30, CD56, and in situ hybridization for EBV-encoded RNA. The patient was diagnosed with cutaneous MTX T-LPD. Four months after discontinuation of MTX, the skin lesions had disappeared. This is the first report of cutaneous MTX T-LPD with CD4+CD30+CD56+EBV+ tumor cells.