The immunoregulatory effects of total glucosides of paeony in autoimmune diseases.

Total glucoside of paeonia (TGP) and its main active ingredient paeoniflorin, extracted from the Chinese herb Paeonia Lactiflora Pallas, exhibit potent immunomodulatory effects. TGP has been shown to inhibit inflammatory responses and disease progression in experimental models of multiple autoimmune diseases (AIDs), including rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, psoriasis, etc. TGP shows broad immunomodulatory effects on many immune cells such as T cells, macrophages, and dendritic cells, by regulating their activation, proliferation, differentiation, and production of effector molecules. Mechanistically, TGP modulates intracellular signaling transductions including JAK/STAT, NF-κB, MAPK, and PI3K/AKT/mTOR pathways. Moreover, TGP has been applied in the clinical treatment of various AIDs with satisfactory therapeutic outcomes and minor side effects. Thus, available studies have demonstrated that TGP and its bioactive constituents exhibit anti-inflammatory and immunomodulatory functions and may have extensive applications in the treatment of AIDs.

The role of epithelial cells in the immunopathogenesis of Sjögren's syndrome.

Sjögren's syndrome is a systemic autoimmune disease characterized by dysfunction of the affected exocrine glands. Lymphocytic infiltration within the inflamed glands and aberrant B-cell hyperactivation are the two salient pathologic features in Sjögren's syndrome. Increasing evidence indicates that salivary gland epithelial cells act as a key regulator in the pathogenesis of Sjögren's syndrome, as revealed by the dysregulated innate immune signaling pathways in salivary gland epithelium and increased expression of various proinflammatory molecules as well as their interaction with immune cells. In addition, salivary gland epithelial cells can regulate adaptive immune responses as nonprofessional antigen-presenting cells and promote the activation and differentiation of infiltrated immune cells. Moreover, the local inflammatory milieu can modulate the survival of salivary gland epithelial cells, leading to enhanced apoptosis and pyroptosis with the release of intracellular autoantigens, which further contributes to SG autoimmune inflammation and tissue destruction in Sjögren's syndrome. Herein, we reviewed recent advances in elucidating the role of salivary gland epithelial cells in the pathogenesis of Sjögren's syndrome, which may provide rationales for potential therapeutic targeting of salivary gland epithelial cells to alleviate salivary gland dysfunction alongside treatments with immunosuppressive reagents in Sjögren's syndrome.

Necroptosis inhibitors: mechanisms of action and therapeutic potential.

Necroptosis is a type of programmed cell death that is morphologically similar to necrosis. This type of cell death is involved in various pathophysiological disorders, including inflammatory, neurodegenerative, infectious, and malignant diseases. Receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like protein (MLKL) pseudokinase constitute the core components of the necroptosis signaling pathway and are considered the most promising targets for therapeutic intervention. The discovery and characterization of necroptosis inhibitors not only accelerate our understanding of the necroptosis signaling pathway but also provide important drug candidates for the treatment of necroptosis-related diseases. Here, we will review recent research progress on necroptosis inhibitors, mechanisms of action and their potential applications for disease treatment.

Single-cell transcriptome profiling reveals immune and stromal cell heterogeneity in primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is a complex autoimmune disease characterized by lymphocytic infiltration and exocrine dysfunction, particularly affecting the salivary gland (SG). We employed single-cell RNA sequencing to investigate cellular heterogeneity in 11 patients with pSS and 5 non-SS controls. Notably, patients with pSS exhibited downregulated SOX9 in myoepithelial cells, potentially associated with impaired epithelial regeneration. An expanded ACKR1+ endothelial subpopulation in patients with pSS suggested a role in facilitating lymphocyte transendothelial migration. Our analysis of immune cells revealed expanded IGHD+ naive B cells in peripheral blood from patients with pSS. Pseudotime trajectory analysis outlined a bifurcated differentiation pathway for peripheral B cells, enriching three subtypes (VPREB3+ B, BANK1+ B, CD83+ B cells) within SGs in patients with pSS. Fibroblasts emerged as pivotal components in a stromal-immune interaction network, potentially driving extracellular matrix disruption, epithelial regeneration impairment, and inflammation. Our study illuminates immune and stromal cell heterogeneity in patients with pSS, offering insights into therapeutic strategies.

Single-cell Clonal Tracing of Glandular and Circulating T cells identifies a population of CD9+CD8+T cells in primary Sjogren's Syndrome.

Primary Sjogren's syndrome (pSS) is a complex chronic autoimmune disease in which local tissue damage in exocrine glands are combined with broader systemic involvement across the body in tissues including the skin. These combined manifestations negatively impact patient health and quality of life. While studies have previously reported differences in immune cell composition in the peripheral blood of pSS patients relative to healthy controls, a detailed immune cell landscape of the damaged exocrine glands of these patients remains lacking. Through single-cell transcriptomics and repertoire sequencing of immune cells in paired peripheral blood samples and salivary gland biopsies, we present here a preliminary picture of adaptive immune response in pSS. We characterize a number of points of divergence between circulating and glandular immune responses that have been hitherto underappreciated, and identify a novel population of CD8+CD9+ cells with tissue-residential properties that are highly enriched in the salivary glands of pSS patients. Through comparative analyses with other sequencing data, we also observe a potential connection between these cells and the tissue-resident memory cells found in cutaneous vasculitis lesions. Together, these results indicate a potential role for CD8+CD9+ cells in mediating glandular and systemic effects associated with pSS and other autoimmune disorders.

Aryl hydrocarbon receptor activation drives polymorphonuclear myeloid-derived suppressor cell response and efficiently attenuates experimental Sjögren's syndrome.

Myeloid-derived suppressor cells (MDSCs) comprise heterogeneous myeloid cell populations with immunosuppressive capacity that contribute to immune regulation and tolerance induction. We previously reported impaired MDSC function in patients with primary Sjögren's syndrome (pSS) and mice with experimental SS (ESS). However, the molecular mechanisms underlying MDSC dysfunction remain largely unclear. In this study, we first found that aryl hydrocarbon receptor (AhR) was highly expressed by human and murine polymorphonuclear MDSCs (PMN-MDSCs). Indole-3-propionic acid (IPA), a natural AhR ligand produced from dietary tryptophan, significantly promoted PMN-MDSC differentiation and suppressive function on CD4+ T cells. In contrast, feeding a tryptophan-free diet resulted in a decreased PMN-MDSC response, a phenotype that could be reversed by IPA supplementation. The functional importance of PMN-MDSCs was demonstrated in ESS mice by using a cell-depletion approach. Notably, AhR expression was reduced in PMN-MDSCs during ESS development, while AhR antagonism resulted in exacerbated ESS pathology and dysregulated T effector cells, which could be phenocopied by a tryptophan-free diet. Interferon regulatory factor 4 (IRF4), a repressive transcription factor, was upregulated in PMN-MDSCs during ESS progression. Chromatin immunoprecipitation analysis revealed that IRF4 could bind to the promoter region of AhR, while IRF4 deficiency markedly enhanced AhR-mediated PMN-MDSC responses. Furthermore, dietary supplementation with IPA markedly ameliorated salivary glandular pathology in ESS mice with restored MDSC immunosuppressive function. Together, our results identify a novel function of AhR in modulating the PMN-MDSC response and demonstrate the therapeutic potential of targeting AhR for the treatment of pSS.

Molecular Mechanism of Sphingosine-1-Phosphate Receptor 1 Regulating CD4+ Tissue Memory in situ T Cells in Primary Sjogren's Syndrome.

OBJECTIVE: Although extensive research has been carried out on CD4+T cells infiltrating the labial glands in patients with primary Sjögren's Syndrome (pSS), it is still unclear how CD4+T cells remain in the labial gland tissue and develop into tissue resident cells. The aim of this study was to investigate the molecular mechanism by which CD4+T reside in labial glandular tissue of pSS patients. METHODS: Lymphocyte infiltration in labial salivary glands (LSG) of pSS patients was detected by H&E staining. Expression of sphingosine-1-phosphate receptor 1 (S1PR1) in LSG was examined by Immunohistochemistry. Immunofluorescence analyses were utilized to detect the co-expression of CD4, CD69 and S1PR1 in T cells of LSG of pSS patients. Expression of gene S1pr1 in peripheral blood CD4+T cells of healthy controls and pSS patients was detected by quantitative real-time PCR (QPCR). QPCR was used to examine the expression of gene S1pr1, Klf2, and Cd69 in the CD4+T cells that were co-cultured in vitro with cytokines TNF-α, TGF-ß, and IL-33. RESULTS: S1PR1 was expressed in the infiltrating monocytes in LSG of pSS patients, and S1PR1 was weakly or even not expressed in cytoplasm of CD4+CD69+TRM cells of LSG in patients with pSS. Expression of gene S1pr1 in peripheral blood CD4+T cells of pSS patients was about three-fifths of that of healthy controls (P < 0.05). Expression of genes S1pr1 (P < 0.001) and Klf-2 (P < 0.001) was significantly decreased, and the expression of gene Cd69 (P < 0.05) was significantly increased in peripheral blood CD4+T cells of pSS patients co-cultured in vitro with cytokines TNF-α, TGF-ß, and IL-33. CONCLUSION: Our study suggests that the decrease of S1pr1 gene expression may provide a molecular basis for promoting the tissue retention and development of CD4+CD69+TRM cells.

Expression profile of PU.1 in CD4+T cells from patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with complex genetic predisposing factors involved. PU.1 is an important member of the ETS transcription factors family which has diverse functions such as regulating the proliferation, differentiation of immune cells and multiple inflammatory cytokines. Previous studies preliminary explored the relation between PU.1 and SLE. To further explain the potential role of PU.1 in the pathogenesis of SLE, 40 SLE patients and 20 age-sex matched healthy controls (HC) were recruited in this study. Flow cytometry was used to test the percentages of CD4+PU.1+T cells in peripheral blood mononuclear cells (PBMCs) from patients with SLE and HC. Expression levels of PU.1 mRNA in CD4+T cells from SLE patients and HC were analyzed by real-time transcription-polymerase chain reaction. Expression levels of plasma IL-1ß, IL-9, IL-18, IL-6, IFN-α, TNF-α, IL-10 and TGF-ß1 were measured by enzyme-linked immunosorbent assay. The percentage of CD4+PU.1+T cells in PBMCs from patients with SLE was significantly higher than that from HC (P < 0.001). In addition, the PU.1 mRNA expression in CD4+T cells from SLE patients was increased than that from HC (P = 0.002). In SLE patients, no significant correlation was found between the percentage of CD4+PU.1+T cells and the expression of PU.1 mRNA in CD4+T cells (P > 0.05). Associations of PU.1 mRNA expression in CD4+T cells with major clinical and laboratory parameters of SLE patients were also analyzed, but no significant correlations were found. Consistent with previous studies, SLE patients had increased IL-1ß, IL-18, IL-6, IFN-α, TNF-α and IL-10 plasma concentrations than HC (P < 0.01). The expression level of plasma TGF-ß1 was significantly decreased in SLE patients than in HC (P < 0.001). In SLE patients, the expression level of IL-1ß was positive correlated with PU.1 mRNA expression in CD4+T cells (P = 0.001). Our study first time evaluated the expression profile of PU.1 in CD4+T cells from SLE patients confirming that PU.1 may participate in the pathogenesis of SLE.

B7-H4 Inhibits the Development of Primary Sjögren's Syndrome by Regulating Treg Differentiation in NOD/Ltj Mice.

BACKGROUND: This study is aimed at exploring the role of B7-H4 in the pathogenesis of primary Sjögren's syndrome (pSS) in NOD/Ltj mouse. METHODS: B7-H4 expression in salivary glands was examined by IHC, and lymphocyte infiltration was showed by H&E. Next, anti-B7-H4 mAb or immunoglobulin isotype was injected into NOD/Ltj mice. Cytokine levels were measured by quantitative RT-PCR, and immunoglobulins were measured by ELISA. T cell subsets were analyzed by flow cytometry. Last, we treated NOD/Ltj mice with B7-H4Ig and control Ig. CD4+Foxp3+ T cells were assessed by immunohistochemistry. Two-tailed Student's t-tests were used to detect the statistical difference in various measures between the two groups. RESULTS: B7-H4 expression was remarkably reduced in salivary glands of NOD/Ltj mice at 15 weeks compared with the NOD/Ltj mice at 8 weeks. Anti-B7-H4 mAb treatment increased lymphocyte infiltration in salivary glands. Inflammatory cytokines including IL-12, IL-18, IL-1α, TNF-α, IFN-α, and BAFF were upregulated markedly in anti-B7-H4 mAb-treated mice compared to IgG isotype-treated mice. Flow cytometry analysis showed that anti-B7-H4 mAb-treated mice had lower levels of CD4+Foxp3+/CD4+ T cells in spleen. Moreover, Foxp3 mRNA levels of salivary glands were diminished in anti-B7-H4 mAb-treated mice. Flow cytometry analysis showed that anti-B7-H4 mAb inhibited CD4+Foxp3+/CD4+ T cell production, while B7-H4Ig would promote naïve CD4+ T into Treg differentiation. Administration with B7-H4Ig displayed significantly decreased lymphocyte infiltration in salivary glands and low levels of total IgM and IgG in serum. Analysis of inflammatory cytokines in salivary glands after B7-H4Ig treatment revealed that the mRNA levels of IL-12, IL-6, IL-18, IL-1α, TNF-α, and IFN-α were significantly downregulated in B7-H4Ig-treated mice compared to control Ig treatment. B7-H4Ig-treated mice had significantly higher levels of CD4+Foxp3+/CD4+ T cells in spleen. IHC in salivary gland revealed that CD4+Foxp3+ T cells of B7-H4Ig treatment mouse were more than control Ig treatment. CONCLUSIONS: Our findings implicate that B7-H4 has a protective role for salivary gland epithelial cells (SGECs) and therapeutic potential in the treatment of pSS.

Injection of CD40 DNA vaccine ameliorates the autoimmune pathology of non-obese diabetic mice with Sjögren's syndrome.

BACKGROUND: Overexpression of CD40 has been reported in patients with primary Sjögren's syndrome (pSS). The increased CD40 expression promote autoimmune response and enhance inflammation in pSS. The aim of this study is to block CD40-CD154 interaction with CD40 DNA vaccine to slow the disease progression of SS in non-obese diabetic (NOD) mice. METHODS: Female NOD mice were treated with CD40 DNA vaccine, empty vector and normal saline. The salivary flow rate was measured, whereas lymphocytes infiltration in the salivary glands was assessed by histopathology. Expression of CD40 and B220 in salivary were examined by immunohistochemistry. Splenic lymphocyte phenotypes were analyzed by flow cytometry. CD40, IL-1ß, TNF-α and IL-6 levels in the salivary glands were detected by PCR. Serum anti-CD40 antibody was measured by ELISA. Serum anti-nuclear antibody (ANA) was monitored by immunofluorescence. RESULTS: NOD mice treated with CD40 DNA vaccine showed higher levels of anti-CD40 antibody compared with the controls. The expression of CD40 in the salivary glands of NOD mice in CD40 DNA vaccine group was decreased. The infiltration of lymphocytes was reduced in the salivary glands and saliva secretion was increased in the treatment group. The expression level of TNF-α and IL-6 in salivary glands were declined. The splenic dendritic cell and plasma cell populations were reduced and the level of ANA was decreased in NOD mice with CD40 DNA vaccine treatment. CONCLUSIONS: CD40 DNA vaccine inhibits the immune response and reduce inflammation in epithelial tissues SS in non-obese diabetic (NOD) mice, suggesting that CD40 DNA vaccine could be a new therapeutic approach in treatment of pSS.

Correction to: the efficacy and safety of total glucosides of peony in the treatment of primary Sjögren's syndrome: a multi-center, randomized, double-blinded, placebo-controlled clinical trial.

The authors regret that the Fig. 1 in the original version of this article contained an error. In the left column, 211 cases in the TGP group should be followed up for 8 weeks before 12 weeks. The correct figure presented in this article.

The efficacy and safety of total glucosides of peony in the treatment of primary Sjögren's syndrome: a multi-center, randomized, double-blinded, placebo-controlled clinical trial.

To evaluate the efficacy and safety of total glucosides of peony (TGP) in adults with primary Sjögren's syndrome (pSS). A multi-center, randomized, double-blinded, placebo-controlled study was conducted between March 2012 and July 2014 at ten Chinese hospitals. In total, 320 pSS patients-classified according to the 2002 American-European Consensus Group Criteria-were randomized (2:1 ratio) to receive TGP(600 mg, tid) in the TGP group or placebo for 24 weeks in the placebo group. Study personnel, investigators, and patients were blinded to the treatment grouping. The primary endpoint was the improvement of EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) at week 24. The secondary endpoints were dry eyes/mouth/skin/nose/throat/vagina visual analogue scale (VAS), pain and discomfort VAS, fatigue VAS, mental discomfort VAS, patient global assessment (PGA), EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI), Schirmer's test, basal/stimulated salivary flow-rate values, and erythrocyte sedimentation rate (ESR). All adverse events were recorded during the trial period. ESSPRI improved more in the TGP than the placebo group (p < 0.001). Dry eyes/throat/vagina VAS, fatigue VAS, mental discomfort VAS, PGA, Schirmer's test, and ESR also improved more in the TGP group than in the placebo group (all p < 0.05). Stimulated salivary flow-rate values increased in the TGP group at week 12 but not at week 24. Adverse events in TGP group were 10.9%. TGP can alleviate some dryness symptoms as well as disease activity in pSS patients over 24 weeks. TGP was well tolerated by study subjects. TGP seems to be an effective and safe treatment for pSS.

Brain magnetic resonance imaging, cerebrospinal fluid, and autoantibody profile in 118 patients with neuropsychiatric lupus.

The objective of this study is to analyze clinical manifestations, features of imaging, and laboratory assessment of patients with neuropsychiatric SLE (NPSLE) for better diagnosis and outcome prediction. One hundred eighteen NPSLE patients admitted to the Anhui Provincial Hospital in Hefei, China, between January 2006 and December 2016 were enrolled and analyzed retrospectively. All patients fulfilled the American College of Rheumatology revised classification criteria for SLE. Patients with NPSLE fulfilled the American College of Rheumatology (ACR) nomenclature and case definitions. All NPSLE patients underwent neurological investigations including MRI of nervous system, electroencephalograms, or CSF examination as part of the diagnostic evaluation of nervous system involvement. All statistical analyses were performed. According to different types of data, different statistical methods were used to determine factors associated with abnormal MRI among NPSLE patients. Statistical significance was defined as P value < 0.05(two-tailed). Twelve different neurological manifestations of NPSLE patients were shown, in which headache was most common symptom (25.95%, 34/131), followed by seizures (25.19%, 33/131), cerebrovascular disease (18.32%, 24/131), psychosis (8.40%, 11/131), and others including mood disorder, cognitive dysfunction, plexopathy, cranial neuropathy, movement disorder, myelopathy, acute confusional state, and anxiety disorder. Thirteen patients have two neurological symptoms at the same time. Cerebrospinal fluid was assessed in 76 NPSLE patients, in which 29 patients had higher pressure of cerebrospinal fluid and 66 patients had abnormal immunoglobulin in cerebrospinal fluid, predominantly with an increase of IgG (84.21%, 64/76), followed by an increase of IgA (69.74%, 53/76), and IgM accounted for 47.74% (34/76). The MRI taken by 66.10% (78/118) patients have shown abnormal lesions and/or ischemic changes in the bilateral cerebral hemisphere, thalamus, pons, brainstem, and cerebellum. The abnormal changes in MRI were correlated with antiphospholipid antibody (APL) and C3 (P = 0.026 and 0.040, respectively). The most common clinical manifestation of NPSLE is headache, followed by seizures and cerebrovascular accident. The test of cerebrospinal fluid and MRI plays an important role in the assessment of NPSLE. The abnormal intracranial lesions were correlated with the level of anti-cardiolipin antibodies (ACL) and C3.

Clinical and immunological consequences of total glucosides of paeony treatment in Sjögren's syndrome: A randomized controlled pilot trial.

BACKGROUND: The total glucosides of paeony (TGP) can inhibit inflammation and alleviate symptoms in autoimmune diseases. This study investigated the clinical and immunological consequences of TGP treatment in patients with primary Sjögren's syndrome (SS). METHODS: We conducted a randomized, double-blinded, placebo-controlled clinical trial in 45 patients with primary SS. Patients were randomized at 2:1 ratio to either TGP group (n=29) or placebo group (n=16) and followed up for 24weeks. The primary outocme was the European League Against Rheumatism Sjögren's Syndrome Patient Reported Index (ESSPRI). The secondary outcomes were stimulated and unstimulated salivary flow rate, Schirmer's test and erythrocyte sedimentation rate (ESR), immuneglobulin (Ig), anti-nuclear antibody (ANA), anti-SSA, and anti-SSB. The proportions of B cells in peripheral blood and the levels of serum inerleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and B cell activating factor belonging to the TNF family (BAFF) were measured at baseline and at the end of follow up of 24weeks. RESULTS: The average score of ESSPRI in both groups had no statistical significance at 24th week. The mean of ESSPRI in the dry-mouth part of questionnaire in patients who scored 3 to 6 points was significantly reduced in the TGP group changed from (4.81±0.60) at baseline to (4.20±1.46) (P=0.027) at week 24. Stimulated salivary flow rate increased at week 24 from (1.80±0.39) to (2.01±0.51) (P=0.031) and unstimulated salivary flow rate increased from (0.65±0.46) to (0.78±0.45) (P=0.011) in the TGP group, but the placebo group showed no significant difference. Erythrocyte sedimentation rate (ESR) was decreased significantly compared to the placebo group at 12- and 24-week from (40.9±18.0) to (29.4±12.2) (P=0.003) and (30.4±17.3) (P=0.024). The percentage of naive B cells decreased at week 24 in the TGP group from (77.34±12.20) to (64.59±15.60) (P=0.005) while memory B cells increased from (21.79±11.97) to (34.21±15.48) (P=0.006) respectively. The concentrations of TNF-α and IFN-γ decreased in the TGP group at week 24 from (32.51±26.67) to (24.22±13.56) (P=0.017) and (10.71±8.94) to (6.55±4.88) (P=0.022), respectively. No significant difference in ANA titer, anti-SSA antibodies, anti-SSB antibodies, C3 concentration or C4 concentration was observed between the two groups. CONCLUSION: TGP appears to improve the glandular secreting function and decrease the level of inflammatory cytokines.

Association of FAM167A-BLK rs2736340 Polymorphism with Susceptibility to Autoimmune Diseases: A Meta-Analysis.

OBJECTIVE: The purpose of this study is to evaluate the correlation between family with sequence similarity 167A-B lymphoid tyrosine kinase (FAM167A-BLK) rs2736340 polymorphism and autoimmune diseases. METHODS: Databases including PubMed, EMBASE, Chinese National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature database (CBM) and Chinese database, Wan Fang database were used in searching eligible studies from January 1, 1966 to October 2, 2015. The odds ratios (ORs) and their 95% confidence intervals (CIs) were pooled to estimate the strength of the association. RESULTS: A total of 25 studies with 30,217 patients and 44,754 controls were included in the meta-analysis. The overall results showed FAM167A-BLK rs2736340 T allele was a risk allele for autoimmune diseases (OR 1.36, 95% CI 1.28-1.44, p < 0.001). In the subgroup by ethnicities, the results suggested T allele was an increased risk in North America, Europe, and Asia (OR 1.33, 95% CI 1.10-1.60, p = 0.004; OR 1.26, 95% CI 1.22-1.31, p < 0.001; and OR 1.46, 95% CI 1.40-1563, p < 0.001, respectively), but not in Africa. Subgroup analysis in different genetic models (recessive, dominant, and additive) revealed significant association between rs2736340 and autoimmune diseases in Asia and North America, but not the recessive model in Europe or Africa, or the additive model in Africa. Stratification analysis by diseases suggested FAM167A-BLK rs2736340 had a positive association with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc) and Kawasaki disease, primary Sjogren's syndrome (pSS), primary antiphosholipid syndrome (APS), and myositis. CONCLUSION: The current meta-analysis suggested that FAM167A-BLK rs2736340 polymorphism is associated with several autoimmune diseases.

Challenges in representation learning: a report on three machine learning contests.

The ICML 2013 Workshop on Challenges in Representation Learning(1) focused on three challenges: the black box learning challenge, the facial expression recognition challenge, and the multimodal learning challenge. We describe the datasets created for these challenges and summarize the results of the competitions. We provide suggestions for organizers of future challenges and some comments on what kind of knowledge can be gained from machine learning competitions.

Labeling Spain with Stanford.

We present an end-to-end framework for outdoor scene region decomposition, learned on a small set of randomly selected images that generalizes well to multiple data sets containing images from around the world. We discuss the different aspects of the framework especially a generalized variational inference method with better approximations to the true marginals of a graphical model. Experimentally, we explain why the framework is robust and performs competitively on many diverse scene data sets, including several unseen scene types. We have obtained high pixel-level accuracies (≈ 80%) in three of the four data sets, which include a benchmark data set known as the Stanford background data set. Our model obtained over 70% accuracy on the fourth data set, which contained a number of indoor and close-up images that are significantly different from our training examples.

Human identification using finger images.

This paper presents a new approach to improve the performance of finger-vein identification systems presented in the literature. The proposed system simultaneously acquires the finger-vein and low-resolution fingerprint images and combines these two evidences using a novel score-level combination strategy. We examine the previously proposed finger-vein identification approaches and develop a new approach that illustrates it superiority over prior published efforts. The utility of low-resolution fingerprint images acquired from a webcam is examined to ascertain the matching performance from such images. We develop and investigate two new score-level combinations, i.e., holistic and nonlinear fusion, and comparatively evaluate them with more popular score-level fusion approaches to ascertain their effectiveness in the proposed system. The rigorous experimental results presented on the database of 6264 images from 156 subjects illustrate significant improvement in the performance, i.e., both from the authentication and recognition experiments.