Decreased blood CD4+PD-1+ and CD8+PD-1+ T cells in psoriatic patients with and without arthritis

Role of ADAM10/17-Mediated Cleavage of LAG3 in the Impairment of Immunosuppression in Psoriasis

Despite extensive research on immune activation regulatory mechanisms, studies on immune suppression in psoriasis are limited. LAG3, a newly identified immune checkpoint, plays a crucial role in modulating immune responses and maintaining T-regulatory cell function. However, its involvement in psoriasis is unclear. We show that psoriasis is associated with reduced LAG3 expression in CD4 T cells and T-regulatory cells. Further analysis revealed that the decline in LAG3 levels was linked to ADAM10/17-mediated proteolytic cleavage, which was upregulated in psoriasis. Clinical utilization of the IL-17A antagonist secukinumab, along with the in vivo and in vitro IL-17A-induced models, supported the potential of IL-17A to induce ADAM10/17 expression and trigger LAG3 cleavage. Through the Jurkat cell model, IL-17A was found to regulate ADAM10/17 expression by activating FOXM1. In addition, treatment with the ADAM10/17 inhibitor GW280264X showed ameliorative effects on psoriasis-like mouse models and lipopolysaccharide-induced inflammation. Collectively, the findings of this study uncover the immune regulatory role of the ADAM10/17-LAG3 axis in psoriasis and highlight the therapeutic potential of targeting ADAM10/17 for psoriasis treatment.

Medical dilemma: Programmed death 1 blockade (sintilimab) therapy in patients suffering from tumours combined with psoriasis

Tumour immunotherapy represented by immune checkpoint inhibitors (ICIs) has greatly improved the overall prognosis of patients with malignant tumours, and is regarded as an important breakthrough in the field of medicine in recent years. ICIs have gradually become the core of tumour therapy and are increasingly used in the clinic. In order to achieve early clinical prediction and management of immune-related adverse events (irAEs), it is still necessary to perform further research on the mechanisms, risk factors, and predictors of irAE occurrence in the future. Zhou et al describe the consultation of a patient with advanced gastric cancer combined with chronic plaque psoriasis. This case provides an important reference for the use of programmed cell death protein-1 (PD-1) inhibitors in patients of tumours combined with chronic plaque psoriasis. This case also highlights that screening of high-risk groups for irAEs is critical before applying PD-1 inhibitors to patients with chronic psoriasis combined with tumours. PD-1 inhibitors are new and potent antineoplastic agents that can cause serious immune-related adverse events such as toxic epidermal necrolysis release and psoriasis. Glucocorticosteroids are the first-line agents for irAEs. The incidence of rheumatic irAEs may be higher in reality, which will inevitably become a new challenge for rheumatologists and dermatologists.

Insufficient PD-1 expression during active autoimmune responses: a deep single-cell proteomics analysis in inflammatory arthritis

Objectives

Programmed cell death protein-1 (PD-1) maintains peripheral immune tolerance by preventing T cell continuous activation. Aiming to understand the extent of PD-1 expression in inflammatory arthritis beyond its involvement with T cells, we assess its presence on various circulating single cells.

Methods

Mass cytometry analysis of patients with active seropositive/seronegative rheumatoid (RA; n=9/8) and psoriatic (PsA; n=9) arthritis versus healthy controls (HC; n=13), re-evaluating patients after 3 months of anti-rheumatic treatment.

Results

PD-1 was expressed in all leukocyte subpopulations, with the highest PD-1+ cell frequencies in eosinophils (59-73%) and T cells (50-60%), and the lowest in natural-killer cells (1-3%). PD-1+ cell frequencies and PD-1 median expression were comparable between patient subgroups and HC, in the majority of cell subsets. Exceptions included increases in certain T cell/B cell subsets of seropositive RA and specific monocyte subsets and dendritic cells of PsA; an expanded PD-1+CD4+CD45RA+CD27+CD28+ T subset, denoting exhausted T cells, was common across patient subgroups. Strikingly, significant inverse correlations between individual biomarkers of systemic inflammation (ESR and/or serum CRP) and PD-1+ cell frequencies and/or median expression were evident in several innate and adaptive immunity cell subsets of RA and PsA patients. Furthermore, all inverse correlations noted in individuals with active arthritis were no longer discernible in those who attained remission/low disease activity post-treatment.

Conclusion

PD-1 expression may be insufficient, relative to the magnitude of the concomitant systemic inflammatory response on distinct leukocyte subsets, varying between RA and PsA. Our results point to the potential therapeutic benefits of pharmacological PD-1 activation, to rebalance the autoimmune response and reduce inflammation.

Drug- or Vaccine-Induced/Aggravated Psoriatic Arthritis: A Systematic Review

INTRODUCTION

Drugs and vaccines have been less studied as inducing or aggravating factors for psoriatic arthritis (PsA) compared with psoriasis. Thus, the present study collected and summarized the publications to date about this issue.

METHODS

We conducted a systematic literature search through the PubMed, Embase, and Cochrane databases to identify all reports on potential drug- and vaccine-related PsA events until 28 February 2023.

RESULTS

In total, 179 cases from 79 studies were eligible for study. Drugs commonly reported include coronavirus disease 2019 (COVID-19) mRNA vaccines (6 cases), bacillus Calmette-Guerin (BCG) vaccine (3 cases), interferon (18 cases), immune-checkpoint inhibitors (ICI) (19 cases), and biologic disease-modifying antirheumatic drugs (bDMARDs) (127 cases). Drugs causing psoriasis may also induce or aggravate PsA (6 cases). BDMARD-related PsA mostly occurred in a "paradoxical" setting, in which the bDMARDs approved for the treatment of psoriasis induce or aggravate PsA. The reported latency may be delayed up to 2 years. Peripheral arthritis (82.3%) was the most common manifestation of drug- and vaccine-related PsA, followed by dactylitis (29.1%), enthesitis (23.4%), and spondyloarthritis (17.7%).

CONCLUSIONS

Drugs and vaccines may be implicated in the aggravation of PsA. Possible mechanisms include cytokine imbalance, immune dysregulation, or inadequate PsA treatment response compared with psoriasis. Most reports are case based without controls, so more studies are needed to further prove the causality. However, early recognition of factors causing or aggravating PsA is important to prevent the irreversible joint damage.

The effect of PD-1/PD-L1 signaling axis on the interaction between CD19+B cells and CD4+T cells in peripheral blood of patients with systemic lupus erythematosus

BACKGROUND

The defect of B cell self-tolerance and the continuous antigen presentation by T cells (TCs) mediated by autoreactive B cells (BCs) play a key role in the occurrence and development of systemic lupus erythematosus (SLE). PD-1/PD-L1 signaling axis negatively regulates the immune response of TCs after activation and maintains immune tolerance. However, the effect of PD-1/PD-L1 signaling axis on the interaction between CD19+B/CD4+TCs in the peripheral blood of patients with SLE has not been studied in detail.

METHODS

PD-1/PD-L1 and Ki-67 levels in peripheral blood (PB) of 50 SLE patients and 41 healthy controls (HCs) were detected through flow cytometry, and then the expression of PD-1+/-cells and PD-L1+/-cells Ki-67 was further analyzed. CD19+B/CD4+TCs were separated for cell culture and the supernatant was collected to determine proliferation and differentiation of TCs. IL-10 and IFN-γ secretion in the supernatant was also determined using ELISA.

RESULTS

The PD-1, PD-L1, and Ki-67 levels on CD19+B/CD4+TCs in patients with SLE were higher than HCs. In CD19+B/CD4+TCs of SLE patients, the proliferative activity of PD-L1+ cells was higher than that of PD-L1- cells, and the proliferative activity of PD-1+ cells was higher than that of PD-1- cells. In the system co-culturing CD19+B/CD4+TCs from HCs/SLE patients, activated BCs promoted TCs proliferation and PD-L1 expression among TCs. Addition of anti-PD-L1 to co-culture system restored the proliferation of TCs, and inhibited IL-10/IFN-γ level. The addition of anti-PD-L1 to co-culture system also restored Tfh and downregulated Treg in HCs.

CONCLUSIONS

Axis of PD-1/PD-L1 on CD19+B/CD4+TCs in PB of SLE patients is abnormal, and cell proliferation is abnormal. In CD19+B/CD4+TCs of SLE patients, the proliferative activity of PD-L1+ and PD-1+ cells compared with PD-L1- and PD-1- cells in SLE patients, respectively. CD19+B/CD4+TCs in SLE patients can interact through PD-1/PD-L1.

The Impact of Biologic Treatment on PD-1/PD-L1 Pathway Disturbances in Psoriasis

The programmed death-1 (PD-1) receptor plays a major physiological role in the maintenance of immune tolerance and, by interaction with its ligands (PD-L1 and PD-L2), prevents the development of multiple immune-mediated diseases. There is growing evidence of the PD-1/PD-L1 pathway playing an important role in the pathogenesis of psoriasis. In total, 84 subjects with psoriasis were included in this study, together with 29 healthy subjects as a control group. Twenty-eight of the psoriatic patients were treated with biologic therapy (TNF-alpha, interleukin (IL)-12/23, or IL-17 inhibitors). The amounts of PD-1- and PD-L1-positive T-cells in peripheral blood were evaluated using flow cytometry. Significantly lower levels of peripheral blood mononuclear cells (PBMCs) with the expression of PD-1 and PD-L1 were found in psoriatic patients compared to healthy individuals, i.e., CD3/PD-1-, CD3/PD-L1-, CD4/PD-1-, CD4/PD-L1-, CD8/PD-L1-, CD19/PD-1-, and CD19/PD-L1-positive cells. Biologic treatment resulted in the elevation of CD3/PD-L1- and CD8/PD-L1- and a decrease in CD8/PD-1-positive PBMCs. Our results confirm previous observations of the PD-1/PD-L1 pathway being disrupted in psoriasis, and that these disturbances may play an important role in development of the disease. Biologic drugs may reverse several abnormalities observed within this pathway, which may explain their excellent efficacy in the treatment of psoriasis. Further research should be conducted to fully explain the results obtained.

Lymphocyte activation gene-3 (LAG-3) regulatory T cells: An evolving biomarker for treatment response in autoimmune diseases

Regulatory T cells (Tregs) comprise a CD4⁺CD25⁺Foxp3⁺ T cell subset for maintaining immune tolerance, and their deficits and/or dysfunction are observed in autoimmune diseases. The lymphocyte activation gene 3 (LAG-3, also known as CD223), which is an immunoglobulin superfamily member expressed on peripheral immune cells, is recognized as an inhibitory regulator of Tregs. LAG-3⁺ T cells represent a novel protective Tregs subset that produces interleukin-10. Alterations in LAG-3⁺ Tregs have been reported in several autoimmune diseases, suggesting their potential pathogenic role. Recent studies have indicated that LAG-3⁺ Tregs may be associated not only with immunopathology but also with response to therapy in several autoimmune and autoinflammatory diseases, such as rheumatoid arthritis, psoriasis, psoriatic arthritis and others. We present a review of Tregs phenotypes and functions, with a focus on LAG-3⁺ Tregs, and discuss their potential role as biomarkers for treatment response in autoimmune diseases.

CD4+ LAG-3+ T cells are decreased in active psoriatic arthritis patients and their restoration in vitro is mediated by TNF inhibitors

Psoriatic arthritis (PsA) is a chronic inflammatory disease associated with T cell dysregulation. The lymphocyte-activation gene (LAG)-3 is one of the regulatory receptors expressed on T cells in a soluble form. LAG-3 expression on T cells was analyzed in vitro in PsA patients with minimal disease activity (MDA), active disease (non-MDA) and healthy controls. In cultured in-vitro peripheral blood mononuclear cells (PBMCs), LAG-3 expression on CD4+ T cells was similar in both MDA PsA patients (7.5 ± 0.9) (n = 14) and healthy controls (7.8 ± 0.6) (n = 15), but significantly lower in non-MDA PsA patients (3.1 ± 0.3) (n = 13) (p < 0.0001). An inverse correlation between PsA clinical disease activity and %CD4+ LAG-3+ T cells in vitro was observed (composite psoriatic disease activity index r = -0.47, p < 0.02 and psoriatic arthritis disease activity score, r = -0.51, p < 0.008). In-vitro co-culture of CD4+ T cells with anti-tumor necrosis factor (TNF) or anti-interleukin (IL)-17A had no effect on LAG-3+ expression in MDA PsA patients and healthy controls. In non-MDA patients, anti-TNF, but not anti-IL-17A, restored the %CD4+ LAG-3+ T cells (7.9 ± 0.9 and 3.2 ± 0.4, respectively) (p < 0.0004). Lower soluble LAG-3 levels were found in sera of naive to biological PsA patients (n = 39) compared to healthy controls (n = 35) (p < 0.03). Impaired LAG-3 on CD4+ T cells may reflect active PsA disease state. Anti-TNFs have potency to up-regulate the CD4+ LAG-3+ T cells in vitro.

Association between PDCD1 gene polymorphisms and psoriasis susceptibility in the Chinese population

BACKGROUND

As an immune regulator expressed on the surface of activated T cells, programmed cell death 1 (PDCD1) plays an important role in psoriasis. However, whether PDCD1 genetic polymorphism is associated with psoriasis has yet to be explored.

OBJECTIVE

To study the association between polymorphisms of the immune-related gene PDCD1 and psoriasis susceptibility in the Chinese population, to illustrate the genetic mechanism of psoriasis and provide new research ideas for the diagnosis and treatment of psoriasis (PS).

METHODS

Overall, 128 psoriasis patients and 88 healthy controls were included in this study. Using polymerase chain reaction (PCR)-Sanger sequencing analysis, six PDCD1 single nucleotide polymorphisms (SNPs) were sequenced: PD1.1, PD1.3, PD1.4, PD1.5, PD1.6, and PD1.9.

RESULTS

Among the six tested SNPs, PD1.6 showed a significant association with psoriasis in genotype and allele frequency distribution. The G allele of PD1.6 increased the risk of psoriasis (P = 0.03). In contrast, the other five SNPs failed to show association with psoriasis. Further analysis within the patient group showed that the frequency of the PD1.6 G allele was relatively high in severe psoriasis, but the difference was nonsignificant.

CONCLUSION

PDCD1 gene polymorphism is associated with psoriasis. The population carrying PD1.6 allele G are at a higher risk of developing psoriasis, though the severity of psoriasis does not correlate with PD1.6 polymorphism.

Differential Function of a Novel Population of the CD19+CD24hiCD38hi Bregs in Psoriasis and Multiple Myeloma

Psoriasis (Ps), an autoimmune disease, and multiple myeloma (MM), a blood neoplasm, are characterized by immune dysregulation resulting from the imbalance between the effector and regulatory cells, including B regulatory (Breg) lymphocytes. Peripheral blood samples from 80 Ps patients, 17 relapsed/refractory MM patients before and after daratumumab (anti-CD38 monoclonal antibody) treatment, 23 healthy volunteers (HVs), and bone marrow samples from 59 MM patients were used in the study. Bregs were determined by flow cytometry using CD19, CD24, and CD38. Intracellular production of interleukin-10 (IL-10) was assessed by flow cytometry after CD40L, LPS, and CpG stimulation. IL-10 serum or plasma concentrations were tested using ELISA method. The percentage of CD19+CD24hiCD38hi Bregs was not different whereas the production of IL-10 in Bregs was significantly higher in Ps patients in comparison with HVs. The percentage of CD19+CD24hiCD38hi Bregs in MM patients was significantly higher than in HVs (p < 0.0001). The percentage of CD19+CD24hiCD38hi Bregs was significantly higher in MM patients with the ISS stage I (p = 0.0233) while IL-10 production in Bregs was significantly higher in ISS stage III (p = 0.0165). IL-10 serum or plasma concentration was significantly higher in Ps and MM patients when compared to HVs (p < 0.0001). Following the treatment with daratumumab the percentages of CD19+CD24hiCD38hi Bregs significantly decreased (p < 0.0003). Here, in the two opposite immune conditions, despite the differences in percentages of Bregs in Ps and MM we have identified some similarities in the IL-10 producing Bregs. Effective treatment of daratumumab besides the anti-myeloma effect was accompanied by the eradication of Bregs.

The PD-1:PD-L1 axis in Inflammatory Arthritis

The activation of antigen specific T cells during an immune response is a tightly regulated process at the level of both costimulatory and coinhibitory receptors. One such coinhibitory receptor or checkpoint inhibitor which has received much attention in the field of oncology is the programmed cell death protein 1 (PD-1). Blockade of PD-1 or its ligand PD-L1 has proven successful in the treatment of a wide variety of cancers, therefore highlighting an important role for this pathway in anti-tumour immune responses. However, a caveat of PD-1 therapy and boosting anti-tumour immune responses is the development of self-reactive T cells which can lead to the induction of various autoimmune or inflammatory diseases, referred to as immune- related adverse events (irAEs). The emergence of rheumatological irAEs such as Inflammatory Arthritis (IA) in recent years has highlighted the importance of PD-1 in maintaining self-tolerance. Furthermore, the emergence of rheumatology related irAEs raises an important question as to how defects in this pathway can contribute to spontaneous rheumatological disease. In this review, we describe the biological distribution, function and regulation of the PD-1 pathway, its potential role in IA and irAE related IA.

The influence of tumour necrosis factor α inhibitors treatment - etanercept on serum concentration of biomarkers of inflammation and cartilage turnover in psoriatic arthritis patients

INTRODUCTION

Effective treatment in psoriatic arthritis (PsA) patients can protect them from severe musculoskeletal complications. For appropriate monitoring of anti-tumour necrosis factor α (anti-TNF-α) treatment in PsA, specific biomarkers are needed.

AIM

To investigate whether biological treatment with anti-TNF-α (etanercept 50 mg once a week subcutaneously) affects the activity of selected mediators of inflammation and destruction of articular cartilage: interleukin-6 (IL-6), interleukin-18 (IL-18), matrix metalloproteinases 1 and 3 (MMP-1, MMP-3), cartilage oligomeric matrix protein (COMP), human cartilage glycoprotein (YKL-40) in serum of patients with PsA.

MATERIAL AND METHODS

The study included 25 patients with PsA. The concentration of IL-6, IL-18, MMP-1, MMP-3, COMP and YKL-40 in serum was determined before, and 6 and 12 weeks after the beginning of anti-TNF-α treatment. Clinical severity of the disease according to the Body Surface Area, Psoriasis Area and Severity Index and Dermatology Life Quality Index as well as tender and swollen joint count (TJC, SJC) were also evaluated.

RESULTS

The study disclosed a statistically significant reduction in the serum concentration of IL-6, MMP-1 and YKL-40 in PsA patients after 6 and 12 weeks from the beginning of anti-TNF-α treatment (p = 0.00018 for IL-6; p = 0.01242 for MMP-1; p = 0.03263 for YKL-40).

CONCLUSIONS

IL-6, MMP-1 and YKL-40 may be useful for monitoring the effectiveness of anti-TNF-α treatment.

Interleukin-18, interleukin-20, and matrix metalloproteinases (MMP-1, MMP-3) as markers of psoriatic arthritis disease severity and their correlations with biomarkers of inflammation and turnover of joint cartilage

Introduction

Psoriatic arthritis (PsA) is a chronic, seronegative spondyloarthropathy characterised by joint inflammation and psoriatic skin changes. Recent data indicate that interleukin-18 (IL-18) and interleukin-20 (IL-20) may be involved in the aetiopathogenesis of PsA.

Aim

To evaluate the potential role of IL-18, IL-20, and matrix metalloproteinases (MMP-1, MMP-3) in the pathogenesis of PsA and their correlations with other markers of inflammation and destruction of joint cartilage, as well as clinical changes.

Material and methods

The study included 24 patients with PsA and 26 healthy volunteers as a control group. The concentration of IL-18 and IL-20, c-reactive protein (CRP), metalloproteinase-1 and -3 (MMP-1, MMP-3), cartilage oligomeric matrix protein (COMP), aggrecan (PG-AG), and human cartilage glycoprotein (YKL-40) in serum was determined. Clinical severity of the disease according to the BSA, PASI, and DLQI as well as tender and swollen joint count (TJC, SJC) were also evaluated.

Results

The concentration of IL-18 was statistically significantly higher in the serum of patients with PsA than in the control group (62.87 pg/ml vs. 16.73 pg/ml, p < 0.0049). Serum IL-20 levels in PsA patients were also higher than in the control group, but without statistical significance (p = 0.2939). The ROC curves showed: AUC = 0.81 for IL-18, AUC = 0.75 for IL-20, AUC = 0.96 for COMP, and AUC = 0.89 for MMP-3.

Conclusions

IL-18 and IL-20 as well as MMP-3 and COMP may be sensitive markers in the diagnosis of PsA.

High intensity interval exercise increases the frequency of peripheral PD-1+ CD8+ central memory T-cells and soluble PD-L1 in humans

Exercise can exert anti-inflammatory effects in an intensity-dependent manner; however, the mechanisms mediating these effects are continually being established. Programme Death Receptor-1 (PD-1) is a membrane bound receptor that maintains immune tolerance by dampening immune cell interactions, such as those mediated by cytotoxic T-cell lymphocytes (CD8⁺). The aim of this study was to characterise sub-populations of CD8⁺ T-cells with regards to their expression of PD-1 before and immediately after exercise. Interleukin (IL)-6, soluble PD-1 (sPD-1) and its ligand (sPD-L1) were also quantified in plasma. Eight individuals (mean ​± ​SD: age 29 ​± ​5 years; BMI 24.2 ​± ​3.4 ​kg ​m²; V˙O_2max 44.5 ​± ​6.4 ​ml ​kg⁻¹·min⁻¹) undertook two time and energy-matched cycling bouts in a counterbalanced study design: one of moderate intensity (MOD) and a bout of high intensity interval exercise (HIIE). Both MOD and HIIE increased the number, but not the proportion of circulating CD8⁺ PD-1+ cells, with no differences between trials. Within the CD8⁺ PD-1+ pool, the expression of PD-1 increased on central memory cells following HIIE only (fold change: MOD 1.0 vs HIIE +1.4), as well the concentration of CD8+PD-1+ memory cells within the circulation (cells/uL: MOD -0.4 vs HIIE +5.8). This response composed a very small part of the exercise-induced CD8⁺ lymphocytosis (Pre-Ex: 0.38% to Post-Ex: 0.69%; p ​> ​0.05). sPD-L1 and IL-6 concentration increased in tandem following MOD and HIIE (r ​= ​0.57; P ​= ​0.021), with a reciprocal decline in sPD-1 observed. The current data demonstrate that PD-1+ CD8⁺ lymphocytes were mobilised following both MOD and HIIE. Both the number of central memory CD8⁺ T-cells expressing PD-1 and the expression level on these cells were increased following HIIE only. This intensity-dependent phenotypic response, in conjunction with increased circulatory sPD-L1 may represent an aspect of the anti-inflammatory response to exercise and warrants further investigation.

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PD-1 is a membrane-bound T-cell receptor that regulates immune tolerance.

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We explored phenotypic changes in PD-1+ T-cells after exercise.

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Circulating PD-1+ CD8⁺ T-cells increased after moderate and high intensity interval exercise (HIIE).

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Central memory CD8⁺ T-cell number and expression increased after HIIE only.

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Post-exercise levels of soluble PD-1 Ligand increased and correlated with IL-6.

Analysis of circulating soluble programmed death 1 (PD-1), neuropilin 1 (NRP-1) and human leukocyte antigen-G (HLA-G) in psoriatic patients

INTRODUCTION

Circulating soluble programmed death 1 (PD-1), neuropilin 1 (NRP-1) and human leukocyte antigen-G (HLA-G) take part in modulating immune tolerance causing disturbances in the molecular mechanisms responsible for maintenance of balance between effector and regulatory components of the immune system. Since their cell-surface expression levels were found to be changed in lesional and/or non-lesional skin of psoriatic patients, analysis of soluble PD-1, NRP-1 and HLA-G concentrations sheds more light on their role in detecting unbalanced immune tolerance in psoriasis.

AIM

To assess soluble PD-1, NRP-1 and HLA-G concentrations in psoriasis.

MATERIAL AND METHODS

The study included 57 psoriatic patients and 29 controls. Duration of psoriasis was in the range 1 to 55 years; the median was 19 years. The plasma concentrations of soluble HLA-G (sHLA-G), soluble NRP-1 (sNRP-1) and soluble PD-1 (sPD-1) were examined using the ELISA method. Severity of the skin lesions was assessed by means of Psoriasis Area Severity Index (PASI), body surface area (BSA) and Physician Global Assessment (PGA).

RESULTS

Psoriasis Area Severity Index in the studied group was in the range 3 to 43; the median was 12. Body surface area was in the range 2-75%; the median was 15%. The median value of PGA was 3. Soluble NRP concentration was significantly higher in the psoriatic patients (median: 1.59 pg/ml; range: 0.67-2.62 pg/ml) than in the control group (median: 1.35 pg/ml; range: 0.05-2.61 pg/ml) (p = 0.010). Soluble PD-1 and sHLA-G concentrations were not significantly different between the studied and control groups (p = 0.094 and p = 0.482, respectively).

CONCLUSIONS

Increased concentrations of sNRP-1 and unchanged values of sHLA-G and sPD-1 concentrations may be indicative of impaired immune tolerance mechanisms in psoriasis.