Quantitative Analysis of the Global Proteome in Peripheral Blood Mononuclear Cells from Patients with New‐Onset Psoriasis

Psoriasis is a common chronic autoimmune skin disease involving the activation of T cells. To explore the proteomic signature of peripheral blood mononuclear cells, a quantitative analysis of their global proteome was conducted in samples from Chinese patients with new‐onset psoriasis (n = 31) and healthy controls (n = 32) using an integrated quantitative approach with tandem mass tag labeling and LC–MS/MS. Protein annotation, unsupervised hierarchical clustering, functional classification, functional enrichment and cluster, and protein–protein interaction analyses were performed. A total of 5178 proteins were identified, of which 4404 proteins were quantified. The fold‐change cutoff was set at 1.2 (patients vs controls); 335 proteins were upregulated, and 107 proteins were downregulated. The bioinformatics analysis indicated that the differentially expressed proteins were involved in processes related to the activation of immune cells including the nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) pathway, cellular energy metabolism, and proliferation. Three upregulated proteins and two phosphorylated proteins in the NF‐κB pathway were verified or identified by Western blotting. These results confirm that the NF‐κB pathway is critical to psoriasis. In addition, many differentially expressed proteins identified in this study have never before been associated with psoriasis, and further studies on these proteins are necessary.     

Affinoleukin in combined treatment of psoriasis

Open randomized controlled clinical trials in which 161 patients were included showed that Affinoleukin (commercial drug which contains low molecular weight proteins obtained from extract of human leukocytes membranes) was effective in treatment of psoriasis. Affinoleukin, when added to regular treatment, accelerated the establishment of remission and its duration by restoration of impaired regulatory and defensive functions of T-lymphocytes, particularly, gamma deltaT- and NKT-cells as well as monocytes and NK-cells. Regular treatment led to marked positive effect in 45% of patients with severe psoriasis and psoriasis of intermediate severity. Addition of Affinoleukin in combined treatment increased proportion of patients with marked positive effect to 72%. Magnitude of Affinoleukin effect was directly related with its dose and severity of psoriasis. Course of Affinoleukin injections (up to 30 units in adults) is worthwhile to use as immunobiological component of combined treatment of exacerbations of severe psoriasis and psoriasis of intermediate severity.     

Combination of abundant protein depletion and multi-lectin affinity chromatography (M-LAC) for plasma protein biomarker discovery

We report on the development of a robust and relatively high-throughput method for in-depth proteomic analysis of human plasma suitable for biomarker discovery. The method consists of depletion of albumin and IgG and multi-lectin affinity chromatography (M-LAC), followed by nanoLC-MS/MS analysis of digested proteins and label-free comparative quantitation of proteins. The performance of the method is monitored by multiple quality control points to ensure reproducibility of the analysis. The method identifies proteins that are reported to be present in normal plasma at concentrations of 10-100 ng/mL and that may be of particular interest when studying a variety of disease conditions. Numerous tissue leakage proteins of potentially even lower concentrations are also identified. When the method was used in a study to identify potential biomarkers of psoriasis, the differential abundance of proteins present at low mug/mL level was quantitated and later verified by ELISA measurements.     

The importance of patient selection for photochemotherapy in psoriasis.

Twenty-four patients with psoriasis were treated with orally administered 8-methoxypsoralen followed by exposure to high-intensity long-wavelength ultraviolet radiation (PUVA) at a psoriasis day care centre. Among the 20 with plaque type psoriasis the condition cleared in 13 (65%), after a mean of 20.7 treatment sessions, and improved but failed to clear in 4 (20%); the treatment failed in the other 3 (15%). The other four patients had erythrodermic, pustular or inflammatory psoriasis, and all failed to respond to PUVA therapy. Factors to be considered in patient selection for this form of therapy are the type of psoriasis, the patient''s skin type and th proportion of the body surface area involved.     

Heterogeneous nuclear ribonucleoproteins C1/C2 identified as autoantigens by biochemical and mass spectrometric methods

The antigenic specificity of an unusual antinuclear antibody pattern in three patient sera was identified after separating HeLa-cell nuclear extracts by two-dimensional (2D) gel electrophoresis and localizing the antigens by immunoblotting with patient serum. Protein spots were excised from the 2D gel and their contents were analyzed by matrix-assisted laser desorption-ionization (MALDI) or nanoelectrospray ionization time-of-flight (TOF) tandem mass spectrometry (MS) after in-gel digestion with trypsin. A database search identified the proteins as the C1 and C2 heterogeneous nuclear ribonucleoproteins. The clinical spectrum of patients with these autoantibodies includes arthritis, psoriasis, myositis, and scleroderma. None of 59 patients with rheumatoid arthritis, 19 with polymyositis, 33 with scleroderma, and 10 with psoriatic arthritis had similar antibodies. High-resolution protein-separation methods and mass-spectrometric peptide mapping in combination with database searches are powerful tools in the identification of novel autoantigen specificities.     

Isobaric tag for relative and absolute quantitation based quantitative proteomics reveals unique urinary protein profiles in patients with preeclampsia

Preeclampsia (PE) is one of the most significant pregnancy‐related hypertensive disorders. Currently, there are no useful markers to predict the onset of the condition in pregnant women. To provide further insights into the pathogenesis of PE and identify biomarkers of the condition, we used isobaric tags for relative and absolute quantitation (iTRAQ) proteomics coupled with 2‐D LC‐MS/MS, to analyze urinary protein profiles from 7 PE patients and 7 normotensive pregnant women. A total of 294 proteins were abnormally expressed in PE patients. Of these, 233 were significantly down‐regulated and 61 proteins were significantly up‐regulated. Bioinformatics analysis using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) database, found that the most differentially expressed proteins (DEPs) were involved in coagulation and complement pathways, the renin‐angiotensin system and cell adhesion molecules (CAMs) pathways. We further validated three of the DEPs, including serotransferrin (TF) and complement factor B (CFB) by immunoblottingand serum paraoxonase/arylesterase 1 (PON1) by ELISA using 14 pairs of urine samples from PE patients and normal pregnant women. Taken together, our results provide the basis for further understanding the pathogenesis of PE and identifying predictive biomarkers.     

银屑病患者血清sPD-1、C反应蛋白及LRG1的表达与病情严重程度的关系

摘要 目的：探讨银屑病患者血清sPD-1、C反应蛋白及LRG1的表达与病情严重程度的关系。方法：选取2019年1月至2022年12月我院收治的银屑病患者70例纳入研究组,并选取同期体检健康者70例纳入对照组。按照患者病情将研究组患者进行进一步分组,分为进行期（21例）、静止期（22例）、退行期（27例）。采用ELISA检测sPD-1、CRP、LRG1的表达水平。采用Pearson检验分析sPD-1、CRP、LRG1的表达与银屑病患者病情的关系;采用logistics回归分析分析银屑病患者不同分期的独立危险因素;采用受试者工作曲线（ROC）分析sPD-1、CRP、LRG1对银屑病患者病情发展的预测价值。结果：三组患者年龄和性别比较（P＞0.05）;进行期sPD-1、CRP、LRG1、PASI积分显著高于静止期和退行期（P<0.05）,静止期sPD-1、CRP、LRG1、PASI积分显著高于退行期（P<0.05）;sPD-1、CRP、LRG1的表达与银屑病分期及PASI评分均显著相关(P<0.05),而与年龄和性别无关（P＞0.05）;多因素logistic回归分析结果显示,sPD-1、CRP、LRG1是影响银屑病患者病情分期的独立危险因素;sPD-1、CRP、LRG1拟合诊断预测银屑病患者病情分期的敏感度86.00%,特异度89.00%,AUC值为0.813。结论：sPD-1、CRP、LRG1的表达上调与银屑病患者疾病分期密切相关,临床早期可通过监测sPD-1、CRP、LRG1的表达对银屑病患者病情的发展做出可靠的预测评估。     

Proteomic analysis of Acinetobacter lwoffii K24 by 2-D gel electrophoresis and electrospray ionization quadrupole-time of flight mass spectrometry

The MS/MS analysis by Electrospray ionization quadrupole-time of flight mass spectrometry (ESI-Q-TOF MS) was applied to identify proteins in proteome analysis of bacteria whose genomes are not known. The protein identification by ESI-Q-TOF MS was performed sequentially by database search and then de novo sequencing using MS/MS spectra. Soil bacteria having unanalyzed genome, Acinetobacter lwoffii K24 is an aniline degrading bacterium. In this report, we present the results of a comparison between the proteome profile of A. lwoffii K24 cultured in aniline- or succinate-containing media. Protein analysis was performed using two-dimensional gel electrophoresis (2-DE) with pH 3-10 immobilized pH gradient (IPG) strips followed by ESI-Q-TOF MS. More than 780 protein spots were detected by 2-DE from the soluble proteome. Forty-eight of these proteins were expressed exclusively in aniline cultured bacteria, and 81 proteins increased and 162 proteins decreased in aniline-cultured versus succinate cultured A. lwoffii K24. Internal amino acid sequences of 43 major protein spots were successfully determined by ESI-Q-TOF MS to try to identify the bacterial proteins responding to aniline culture condition. Since the A. lwoffii K24 genome is not yet sequenced, many proteins were found to be hypothetical. Comparative proteome analysis of the insoluble protein fractions showed that one novel protein that was strongly induced by succinate-cultured A. lwoffii K24 was repressed under aniline culture conditions. These results suggest that comprehensive analysis of bacterial proteomes by 2-DE and amino acid sequence analysis by ESI-Q-TOF MS is useful for understanding induced novel proteins of biodegrading bacteria.     

寻常型银屑病患者血清IL-17、IL-18、VEGF的表达及与病情严重程度的相关性研究

目的:探讨寻常型银屑病患者血清白介素17(IL-17)、白介素18(IL-18)、血管内皮生长因子(VEGF)的表达及与病情严重程度的相关性。方法:选取2015年8月到2017年4月在我院接受治疗的寻常型银屑病患者86例为研究组,另选取同期在我院体检结果为健康的志愿者40例作为健康对照组,并根据临床症状和病情变化对研究组患者进行分组,其中进行期银屑病组32例,静止期银屑病组24例,退行期银屑病组30例。对比研究组和健康对照组血清中IL-17、IL-18、VEGF水平,对比不同严重程度的寻常型银屑病患者血清中IL-17、IL-18、VEGF水平和PASI评分,采用Spearman相关性分析IL-17、IL-18、VEGF的表达与PASI评分的相关性。结果:研究组患者血清中的IL-17、IL-18、VEGF水平显著高于健康对照组(P0.05),进行期银屑病组患者血清中IL-17、IL-18、VEGF水平和PASI评分显著高于静止期银屑病组和退行期银屑病组,静止期银屑病组患者血清中IL-17、IL-18、VEGF水平和PASI评分显著高于退行期银屑病组(P0.05),Spearman相关性分析结果显示,研究组患者血清中IL-17、IL-18、VEGF水平与PASI评分均呈正相关(P0.05)。结论:寻常型银屑病患者血清中IL-17、IL-18、VEGF水平异常升高,且其水平与病情严重程度有关,对上述三种指标进行监测有助于临床治疗寻常型银屑病。     

Quantitative proteomics suggests decrease in the secretogranin‐1 cerebrospinal fluid levels during the disease course of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS with unknown cause. Proteins with different abundance in the cerebrospinal fluid (CSF) from relapsing‐remitting MS (RRMS) patients and neurological controls could give novel insight to the MS pathogenesis and be used to improve diagnosis, predict prognosis and disease course, and guide in therapy decisions. We combined iTRAQ labeling and Orbitrap mass spectrometry to discover proteins with different CSF abundance between six RRMS patients and 18 neurological disease controls. From 777 quantified proteins seven were selected as biomarker candidates, namely chitinase‐3‐like protein 1, secretogranin‐1 (Sg1), cerebellin‐1, neuroserpin, cell surface glycoprotein MUC18, testican‐2 and glutamate receptor 4. An independent sample set of 13 early‐MS patients, 13 RRMS patients and 13 neurological controls was used in a multiple reaction monitoring verification study. We found the intracellular calcium binding protein Sg1 to be increased in early‐MS patients compared to RRMS and neurological controls. Sg1 should be included in further studies to elucidate its role in the early phases of MS pathogenesis and its potential as a biomarker for this disease.     

TCR Peptide Therapy in Human Autoimmune Diseases

Inflammatory Th1 cells reacting to tissue/myelin derived antigens likely contribute to the pathogenesis of diseases such as multiple sclerosis (MS), rheumatoid arthritis (RA), and psoriasis. One regulatory mechanism that may be useful for treating autoimmune diseases involves an innate second set of Th2 cells specific for portions of the T cell receptor of clonally expanded pathogenic Th1 cells. These Th2 cells are programmed to respond to internally modified V region peptides from the T cell receptor (TCR) that are expressed on the Th1 cell surface in association with major histocompatibility molecules. Once the regulatory Th2 cells are specifically activated, they may inhibit inflammatory Th1 cells through a non-specific bystander mechanism. A variety of strategies have been used by us to identify candidate disease-associated TCR V genes present on pathogenic Th1 cells, including BV5S2, BV6S5, and BV13S1 in MS, BV3, BV14, and BV17 in RA, and BV3 and BV13S1 in psoriasis. TCR peptides corresponding to the mid region of these BV genes were found to be consistently immunogenic in vivo when administered either i.d. in saline or i.m. in incomplete Freund's adjuvant (IFA). In MS patients, repeated injection of low doses of peptides (100-300 g) significantly boosted the number of TCR-reactive Th2 cells. These activated cells secreted cytokines, including IL-10, that are known to inhibit inflammatory Th1 cells. Cytokine release could also be induced in TCR-reactive Th2 cells by direct cell-cell contact with Th1 cells expressing the target V gene. These findings indicate the potential of regulatory Th2 cells to inhibit not only the target Th1 cells, but also bystander Th1 cells expressing different V genes specific for other autoantigens. TCR peptide vaccines have been used in our studies to treat a total of 171 MS patients (6 trials), 484 RA patients (7 trials), and 177 psoriasis patients (2 trials). Based on this experience in 824 patients with autoimmune diseases, TCR peptide vaccination is safe and well tolerated, and can produce significant clinical improvement in a subset of patients that respond to immunization. TCR peptide vaccination represents a promising approach that is well-suited for treating complex autoimmune diseases.     

Moesin and Stress-Induced Phosphoprotein-1 Are Possible Sero-Diagnostic Markers of Psoriasis

To identify diagnostic markers for psoriasis vulgaris and psoriatic arthritis, autoantibodies in sera from psoriasis vulgaris and psoriatic arthritis patients were screened by two-dimensional immunoblotting (2D-IB). Based on 2D-IB and MADLI TOF/TOF-MS analyses, eleven proteins each in psoriasis vulgaris and psoriatic arthritis were identified as autoantigens. Furthermore, serum levels of moesin, keratin 17 (K17), annexin A1 (ANXA1), and stress-induced phophoprotein-1 (STIP1), which were detected as autoantigens, were studied by dot blot analysis with psoriasis patients and healthy controls. The levels of moesin and STIP1 were significantly higher in sera from patients with psoriasis vulgaris than in the controls (moesin: P<0.05, STIP1: P<0.005). The area under the curve (AUC) for moesin and STIP1 between patients with psoraisis vulgaris and controls was 0.747 and 0.792, respectively. STIP1 and K17 levels were significantly higher in sera from patients with psoriatic arthritis than in those with psoriasis vulgaris (P<0.05 each). The AUC for STIP1 and K17 between patients with psoriatic arthritis and psoriasis vulgaris was 0.69 and 0.72, respectively. The STIP1 or moesin, CK17 serum level was not correlated with disease activity of psoriasis patients. These data suggest that STIP1 and moesin may be novel and differential sero-diagnostic markers for psoriasis vulgaris and psoriatic arthritis.     

Cell surface shaving of Candida albicans biofilms, hyphae, and yeast form cells

We used a brief trypsin treatment followed by peptide separation and identification using nano-LC followed by off-line MS/MS to identify the surface proteins on live Candida albicans organisms growing in biofilms and planktonic yeast cells and hyphae. One hundred thirty-one proteins were present in at least two of the three replicates of one condition and distributed in various combinations of the three growth conditions. Both previously reported and new surface proteins were identified and these were distributed between covalently attached proteins and noncovalently attached proteins of the cell wall.     

Proteolytic peptide patterns as indicators for fungal infections and nonfungal affections of human nails measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The discrimination of onychomycoses from endogenous diseases showing macroscopically similar symptoms is difficult. Long-lasting but ineffective antifungal therapies using systemic medicaments with often severe adverse reactions may be the consequence. We introduce a novel mass spectrometric method for the discrimination of fungal infections and nonfungal affections. Horn samples from patients infected by Trichophyton rubrum, from patients with psoriasis affecting nails, and from healthy persons were investigated. Onychomycoses are basically associated with proteolytic attacks of the virulent fungi-secreting proteases partly hydrolyzing the horn material. Endogenous diseases lack these proteolytic activities, conserving intact structural proteins. Tryptical digestion of horn material produced cleavage peptides detectable by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Mass spectra of horn material infected by T. rubrum were clearly different from those originating from healthy test persons and from patients with psoriasis. Two methods were successfully applied to quantify the differences between groups of samples. One is based on the Euclidean match factor, and the other is based on the identification of specific peptide peaks occurring exclusively within one group of persons. The Euclidean match factor distributions and the occurrence of specific peptide peaks allowed a clear differentiation of T. rubrum infections from psoriasis patients and healthy test persons. No differences were found between healthy test persons and psoriasis patients. The method is rapid and does not require any cultivation.     

Osteopontin,CCL5 and CXCL9 are independently associated with psoriasis,regardless of the presence of obesity

Psoriasis is an autoimmune disease associated with the production of pro-inflammatory cytokines. The identification of these molecules in the pathogenesis of psoriasis facilitated the use of monoclonal antibodies to block their actions as a treatment for severe psoriasis. An increased inflammatory response has been documented in patients with obesity, a condition that is associated with the occurrence and severity of psoriasis. Osteopontin (OPN), TNF and CXCL9 levels are enhanced in patients with psoriasis, although OPN has been documented in the adipose tissue of obese patients without psoriasis. The prevalence of obesity is much higher in psoriasis patients compared with the general population. Thus, we aimed to evaluate the relationship between cytokine levels and psoriasis in the context of obesity. We compared OPN and CXCL9 plasma levels among 117 psoriasis patients and 27 healthy body mass index-matched subjects using ELISA. We also analyzed the TNF, CCL2 and CCL5 levels in a smaller subgroup of patients and matched controls. Median OPN, CCL5 and CXCL9 levels were significantly higher in psoriasis patients compared with the controls, independent of obesity. There was no difference between the median CCL2 levels in the psoriasis patients and the controls (P < 0.05), although the CCL2 levels were elevated in obese patients compared with non-obese psoriasis patients (P < 0.001). Facial involvement and the psoriasis area severity index (PASI) score were not associated (P < 0.05) with OPN levels or elevated levels of chemokines. There was no significant correlation between the OPN and CXCL9 levels or the OPN and TNF levels in psoriasis patients. This work confirms that OPN, CCL5 and CXCL9 plasma levels are higher in psoriasis patients and provides evidence that their higher levels are not a consequence of obesity. Furthermore, the results demonstrate that OPN production is independent of TNF-α and CXCL9.     

Serum proteome of leprosy patients undergoing erythema nodosum leprosum reaction: regulation of expression of the isoforms of haptoglobin

Validated proteome profile allows better understanding of disease progression, subtype classification, susceptibility patterns, and disease prognosis. Leprosy is a spectral disease, with clinically, histologically, immunologically, and bacteriologically distinguishable subtypes. In addition, a significant fraction of patients undergo immune mediated reactions even after multidrug therapy (MDT). Erythema nodosum leprosum (ENL) is an immune complex mediated reactional condition in leprosy, characterized by a systemic inflammatory condition afflicting borderline lepromatous (BL) and lepromatous leprosy patients (LL). In this study, we have analyzed serum proteome of leprosy patients undergoing ENL reactions and compared it with that of healthy noncontact controls. Depletion of albumin and immunoglobulin G (IgG) was optimized using Aurum serum protein mini kit (Bio-Rad), and then two-dimensional gel electrophoresis (2-DE) of these serum samples was performed. Differentially expressed proteins were identified by MALDI-TOF and MALDI-TOF MS/MS mass spectrometry. Significant increase in one of the isoforms of alpha2 chain of haptoglobin was observed in ENL condition. In addition, haptoglobin phenotype was determined for healthy controls and leprosy patients. Hp 0-0 phenotype was detected in 21.4% of the ENL patients undergoing treatment, which on follow up examination showed typable phenotype, thus showing a condition of acquired anhaptoglobinemia. Since ENL still remains a threat to leprosy disease management, the above findings may provide new insights in understanding the development and progression of this inflammatory condition.     

Sub-proteome analysis of novel IgE-binding proteins from Bermuda grass pollen

Bermuda grass (Cynodon dactylon) pollen (BGP) is one of the most common causes of airway allergic disease, and has been shown to contain over 12 allergenic proteins on 1-D immunoglobulin E (IgE) immunoblots. However, only a few allergens have been identified and characterized. Cyn d 1 is a major allergen and the most abundant protein in BGP, representing 15% of the whole-pollen extract. To investigate variability in the IgE-reactive patterns of BGP-sensitized patients and to identify other prevalent allergens, a BGP extract was passed through an affinity column to remove Cyn d 1, and the non-bound material was collected and analyzed by 2-DE. IgE-reactive proteins were subsequently characterized by immunoblotting using serum samples from ten BGP-allergic patients. The prevalent IgE-reactive proteins were identified by MALDI-TOF MS, N-terminal sequence similarity, and LC-MS/MS. Here, we present a sub-proteome approach for allergen investigation and its use for determining BGP 2-DE profiles and identifying six novel allergens.     

Psoriasis alters HDL composition and cholesterol efflux capacity

Psoriasis, a chronic inflammatory skin disease, has been linked to increased myocardial infarction and stroke. Functional impairment of HDL may contribute to the excess cardiovascular mortality of psoriatic patients. However, data available regarding the impact of psoriasis on HDL composition and function are limited. HDL from psoriasis patients and healthy controls was isolated by ultracentrifugation and shotgun proteomics, and biochemical methods were used to monitor changed HDL composition. We observed a significant reduction in apoA-I levels of HDL from psoriatic patients, whereas levels of apoA-II and proteins involved in acute-phase response, immune response, and endopeptidase/protease inhibition were increased. Psoriatic HDL contained reduced phospholipid and cholesterol. With regard to function, these compositional alterations impaired the ability of psoriatic HDL to promote cholesterol efflux from macrophages. Importantly, HDL-cholesterol efflux capability negatively correlated with psoriasis area and severity index. We observed that control HDL, as well as psoriatic HDL, inhibited dihydrorhodamine (DHR) oxidation to a similar extent, suggesting that the anti-oxidative activity of psoriatic HDL is not significantly altered. Our observations suggest that the compositional alterations observed in psoriatic HDL reflect a shift to a pro-inflammatory profile that impairs cholesterol efflux capacity of HDL and may provide a link between psoriasis and cardiovascular disease.     

Quantitative tandem mass-spectrometry of skin tissue reveals putative psoriatic arthritis biomarkers

Background

Psoriatic arthritis (PsA) is a distinct inflammatory arthritis occurring in 30% of psoriasis patients. There is a high prevalence of undiagnosed PsA in psoriasis patients; therefore, identifying soluble biomarkers for PsA could help in screening psoriasis patients for appropriate referral to a rheumatologist. Potential PsA biomarkers likely originate in sites of inflammation, such as the skin, and subsequently enter systemic circulation. Our goal was to identify candidate PsA biomarkers by comparing the proteome of skin biopsies obtained from patients with PsA to that from patients with psoriasis without PsA.

Methods

Skin biopsies were obtained from involved and uninvolved skin of 10 PsA and 10 age/gender-matched psoriasis patients without PsA (PsC). Using strong cation exchange chromatography, followed by label-free quantitative tandem mass spectrometry, we characterized the proteomes of pooled skin samples. Extracted ion current intensities were used to calculate protein abundance ratios, and these were utilized to identify differentially regulated proteins.

Results

Forty-seven proteins were elevated in PsA-derived skin compared to PsC-derived skin. Selected reaction monitoring assays were developed to quantify these potential PsA markers in individual skin samples, and 8 markers were confirmed in an independent sample set. ITGB5 and POSTN were measured in serum samples from 33 PsA and 15 PsC patients, using enzyme-linked immunosorbent assays. ITGB5 was significantly elevated in PsA serum (P < 0.01), and POSTN showed a trend. ITGB5 and POSTN correlated significantly in both patient groups (r = 0.472, P < 0.001).

Conclusion

Proteomic analysis of PsA and PsC skin identified eight new candidate biomarkers. These markers need to be validated with a larger and independent cohort, in order to delineate their clinical utility in PsA patients. These proteins may also uncover unknown aspects of PsA pathobiology.

Electronic supplementary material

The online version of this article (doi:10.1186/1559-0275-12-1) contains supplementary material, which is available to authorized users.