RIPK4 regulates cell-cell adhesion in epidermal development and homeostasis.

Epidermal development and maintenance are finely regulated events requiring a strict balance between proliferation and differentiation. Alterations in these processes give rise to human disorders such as cancer or syndromes with skin and annexes defects, known as ectodermal dysplasias (EDs). Here, we studied the functional effects of two novel receptor-interacting protein kinase 4 (RIPK4) missense mutations identified in siblings with an autosomal recessive ED with cutaneous syndactyly, palmoplantar hyperkeratosis and orofacial synechiae. Clinical overlap with distinct EDs caused by mutations in transcription factors (i.e. p63 and interferon regulatory factor 6, IRF6) or nectin adhesion molecules was noticed. Impaired activity of the RIPK4 kinase resulted both in altered epithelial differentiation and defective cell adhesion. We showed that mutant RIPK4 resulted in loss of PVRL4/nectin-4 expression in patient epidermis and primary keratinocytes, and demonstrated that PVRL4 is transcriptionally regulated by IRF6, a RIPK4 phosphorylation target. In addition, defective RIPK4 altered desmosome morphology through modulation of plakophilin-1 and desmoplakin. In conclusion, this work implicates RIPK4 kinase function in the p63-IRF6 regulatory loop that controls the proliferation/differentiation switch and cell adhesion, with implications in ectodermal development and cancer.

A Longitudinal Multiinstitutional Study of Vulvar Lichen Sclerosus: From Childhood to Perimenopause.

OBJECTIVE: The main outcome of this study was the evaluation of clinical characteristics, comorbidities, and therapeutic approaches in patients with vulvar lichen sclerosus (VLS) aged from childhood to perimenopause. Secondly, it was intended to compare these characteristics according to the menarchal status. METHODS: Patients less than 45 years of age with a diagnosis of VLS from January 2002 to June 2022 in 10 referral centers were included in this retrospective longitudinal study. The univariate analysis compared the dependent variables according to menarchal status. RESULTS: One hundred eighty-six patients met the inclusion criteria. At diagnosis, between 25% and 40% of premenarchal patients reported signs related to subepithelial hemorrhage. A significantly greater presence of bleeding (p < .005), easy bruising (p = .028), fissures (p = .008), petechiae/splinter hemorrhages (p < .001), and bleeding/blistering or open sores (p = .011) was observed in premenarchal patients with respect to the postmenarchal group. The perineum (p = .013) and the perianal region (p < .001) were significantly more involved in the premenarchal group. Topical calcineurin inhibitors were more used in the premenarchal population (p = .004), whereas vitamin E oil and moisturizers were more used in the postmenarchal population (p = .047). CONCLUSIONS: Vulvar lichen sclerosus is a chronic condition that can cause vulvar changes that result in severe morbidity and affects sexual function and quality of life, even before menopause. Vulvar lichen sclerosus continues to be misdiagnosed in this population. This may lead to an average delay from symptom onset to diagnosis. Evaluating clinical manifestations of VLS in premenarchal and postmenarchal age allowed us to find different clinical characteristics between the 2 periods suggestive of the diagnosis.

The combined role of clinical, reflectance confocal microscopy and dermoscopy applied to chronic discoid cutaneous lupus and subacutus lupus erythematosus: A case series and literature review.

Main subtypes of cutaneous lupus erythematosus are represented by acute, subacute cutaneous, intermittent and chronic cutaneous lupus erythematosus. Discoid lupus erythematosus represents the most common phenotype of chronic cutaneous lupus erythematosus. The spectrum of clinical manifestations mirrors that of several and distinct histopathological features. Such variability among different CLE subtypes is also observed at dermoscopy. Dermoscopy is nowadays considered an additional valuable method for skin lesions assessment in general dermatology, following and completing the well-known clinical diagnostic steps, such as medical history and clinical examination. In vivo reflectance confocal microscopy (RCM) is a non-invasive imaging tool able to assess the epidermis and upper dermis producing high resolution (horizontal ∼1.25 µm, vertical ∼5 µm), en face tissue sections used for melanocytic and inflammatory evaluation. In this study, we reported dermoscopic and RCM features about 9 patients affected by subacute and chronic lupus erythematosus retrospectively analyzed.

Cutaneous mastocytosis: A dermatological perspective.

Mastocytosis is a rare disease characterised by expansion and collection of clonal mast cells in various organs including the skin, bone marrow, spleen, lymph nodes and gastrointestinal tract. The prevalence of mastocytosis has been estimated to be one in 10 000, while the estimated incidence is one per 100 000 people per year. Cutaneous mastocytosis is classified into (i) maculopapular cutaneous mastocytosis, also known as urticaria pigmentosa; (ii) diffuse cutaneous mastocytosis; and (iii) mastocytoma of the skin. In adults, cutaneous lesions are usually associated with indolent systemic mastocytosis and have a chronic evolution. Paediatric patients, on the contrary, have often cutaneous manifestations without systemic involvement and usually experience a spontaneous regression. Diagnosis of cutaneous mastocytosis may be challenging due to the rarity of the disease and the overlap of cutaneous manifestations. This short review describes pathogenesis and clinical aspects of cutaneous mastocytosis with a focus on diagnosis and currently available therapies.

Clindamycin versus clindamycin plus rifampicin in hidradenitis suppurativa treatment: Clinical and ultrasound observations.

BACKGROUND: Antibiotics are recognized as first-line treatments for hidradenitis suppurativa (HS), but the data on their efficacy are limited. OBJECTIVE: Evaluate the efficacy of oral clindamycin versus that of clindamycin plus rifampicin in patients with HS. METHODS: A total of 60 patients with mild-to-moderate-severe HS who were classified according to their International Hidradenitis Suppurativa Severity Score System (IHS4) and Hurley scores, were subdivided into 2 groups of 30 patients each (group A, the members of which received clindamycin plus rifampicin, and group B, the members of which were treated with clindamycin alone) and retrospectively studied. The main objective was to evaluate and compare the clinical and ultrasound responses between the groups after 8 weeks of treatment according to the Hidradenitis Suppurativa Clinical Response measure. RESULTS: After the treatment, 17 of 30 patients in group A and 19 of 30 in group B met the primary outcome. Both groups showed a similar improvement of IHS4 score, whereas the Dermatology Life Quality Index and pain Visual Analogue Scale scores improved more in group B. In particular, the reductions in nodule and abscess counts were similar between the 2 groups, whereas the number of draining tunnels decreased more in group B. The factors significantly associated with Hidradenitis Suppurativa Clinical Response score were age, body mass index, IHS4 score, and absence of axillary involvement. Disease-free survival was similar between the 2 groups. LIMITATIONS: The study was not randomized or placebo-controlled. CONCLUSION: Clindamycin may be a useful treatment alternative to antibiotic combination regardless of HS clinical stage.

Effects of topical methotrexate loaded gold nanoparticle in cutaneous inflammatory mouse model.

Gold nanoparticles functionalized with 3-mercapto-1-propansulfonate (AuNPs-3MPS) have been prepared and loaded with Methotrexate (MTX), an immunosuppressive agent used in the systemic treatment of moderate-severe inflammatory diseases. The effects of the AuNPs-3MPS@MTX topically administered in vitro on skin model and in vivo on imiquimod-induced psoriasis-like mice model, have been studied. Clinical response, epidermal thickness, cell proliferation rate and inflammation were tested. AuNPs-3MPS@MTX treated mice showed a decreasing of scaling and erythema score, reduction of epidermal thickness, parakeratosis and hyperkeratosis, compared to AuNPs-3MPS treated mice. Immunohistochemistry analysis staining displayed that Ki67, K6 CD3 and CD8 stainings were reduced in AuNPs-3MPS@MTX treated mice. Blood evaluation showed no differences in blood count and in ALT and AST levels before and after AuNPs-3MPS or AuNPs-3MPS@MTX treatment. Topical AuNPs-3MPS@MTX treatment is able to induce a reduction of keratinocytes hyperproliferation, epidermal thickness and also inflammatory infiltrate in vivo on imiquimod-induced psoriasis like mice model.

IL12B (p40) Gene Polymorphisms Contribute to Ustekinumab Response Prediction in Psoriasis.

BACKGROUND: Psoriasis is characterized by multiple genetic variations. Some of these variations, such as the presence of HLA-Cw6 or TNFAIP3 single-nucleotide polymorphisms (SNPs), have been correlated to the response to biologic treatments. OBJECTIVE: The aim of our study was to evaluate the effects of IL12B and IL6 SNPs on the response to ustekinumab. METHODS: We retrospectively analyzed the genotypes of 64 patients who had been treated with ustekinumab for up to 1 year. Efficacy data were evaluated using 'intention to treat-last observation carried forward' analysis. RESULTS: We confirmed the positive role of HLA-Cw6 as a predictor of the response to ustekinumab and discovered that presence of the GG genotype on the IL12B rs6887695 SNP and absence of the AA genotype on the IL12B rs3212227 SNP significantly increase the probability of therapeutic success in HLA-Cw6 positive patients. CONCLUSIONS: The availability of pharmacogenetic data will influence therapeutic decisions in the clinical management of psoriatic patients.

Developmental factor IRF6 exhibits tumor suppressor activity in squamous cell carcinomas.

The transcription factor interferon regulatory factor 6 (IRF6) regulates craniofacial development and epidermal proliferation. We recently showed that IRF6 is a component of a regulatory feedback loop that controls the proliferative potential of epidermal cells. IRF6 is transcriptionally activated by p63 and induces its proteasome-mediated down-regulation, thereby limiting keratinocyte proliferative potential. We hypothesized that IRF6 may also be involved in skin carcinogenesis. Hence, we analyzed IRF6 expression in a large series of squamous cell carcinomas (SCCs) and found a strong down-regulation of IRF6 that correlated with tumor invasive and differentiation status. IRF6 down-regulation in SCC cell lines and primary tumors correlates with methylation on a CpG dinucleotide island located in its promoter region. To identify the molecular mechanisms regulating IRF6 potential tumor suppressive activity, we performed a genome-wide analysis by combining ChIP sequencing for IRF6 binding sites and gene expression profiling in primary human keratinocytes after siRNA-mediated IRF6 depletion. We observed dysregulation of cell cycle-related genes and genes involved in differentiation, cell adhesion, and cell-cell contact. Many of these genes were direct IRF6 targets. We also performed in vitro invasion assays showing that IRF6 down-regulation promotes invasive behavior and that reintroduction of IRF6 into SCC cells strongly inhibits cell growth. These results indicate a function for IRF6 in suppression of tumorigenesis in stratified epithelia.

Detection of adalimumab and anti-adalimumab levels by ELISA: clinical considerations.

Psoriasis (Ps) is a common and stigmatizing chronic inflammatory skin disease that may cause other chronic inflammatory conditions with overlapping pathology, such as rheumatoid arthritis (RA). Tumor necrosis factor (TNF) is a proinflammatory cytokine that plays a pivotal role in chronic inflammatory and autoimmune diseases such as uveitis, multiple sclerosis, systemic lupus, arthritis, Ps, and Crohn's disease. The TNF superfamily and receptors represent active targets for drug development. Anti-TNF biological therapies, such as infliximab, adalimumab (ADL), and etanercept, are effective in treating RA, spondyloarthritis, Ps, and inflammatory bowel diseases, but long-term treatment can induce anti-drug antibody (ADA) formation associated with lower drug levels and clinical nonresponse. An investigation of the relationship between serum ADL/anti-adalimumab antibody (AAA) concentration, and clinical response in moderate to severe Ps, confirmed an association between ADL and AAA levels and response. Although the detection of ADAs can be used to determine the cause of nonresponse and aid therapy decisions, the contrary observation of long-term responders with low drug levels and detectable ADA suggests that another mechanism is also involved.

Long-Term Effectiveness of Brodalumab for the Treatment of Moderate-To-Severe Psoriasis: A Real-Life Multicenter Study of Up to 3 Years in a Real-Life Italian Cohort.

INTRODUCTION: Data about the long-term effectiveness of brodalumab could be valuable in assessing patient adherence to treatment and improving psoriasis management. OBJECTIVE: The aim of our study was to evaluate the drug survival of brodalumab and identify any predictive factors for discontinuation. METHODS: A multicenter retrospective study was conducted in patients with moderate-to-severe psoriasis who were treated for up to 3 years. We extracted data from patient files, related to the characteristics of the patients and the disease. Drug survival analysis was descriptively analyzed using Kaplan-Meier survival curves. Univariable and multivariable analyses were performed to assess baseline patient characteristics that predicted clinical response. RESULTS: The study included 90 patients. Among them, 28 (31.1%) suspended brodalumab through the observation period. At weeks 52, 104 and 156 the median PASI score were 0.0 [0.0 - 0.8], 0.0 [0.0 - 1.0] and 0.0 [0.0 - 0.0], respectively. The estimated cumulative survival rates at weeks 52 and 104 were 86.32% and 78.09%, respectively. In the multivariable survival analysis, predictor factors for overall discontinuation included body mass index (BMI) (OR 1.10, 95% CI 1.03 - 1.18), baseline PASI (OR 1.06, 95% CI 1.02 - 1.10), and psoriatic arthritis (OR 5.05, 95% CI 0.89 - 13.50). CONCLUSIONS: Brodalumab has shown long-term effectiveness for up to 3 years. Considering baseline disease severity and patient characteristics could aid in optimizing the long-term management of psoriasis.

IL-21 promotes skin recruitment of CD4(+) cells and drives IFN-γ-dependent epidermal hyperplasia.

Psoriasis is a chronic inflammatory disorder of the skin characterized by epidermal hyperplasia and infiltration of leukocytes into the dermis and epidermis. T cell-derived cytokines, such as IFN-γ and IL-17A, play a major role in the psoriasis-associated epidermal hyperplasia, even though factors/mechanisms that regulate the production of these cytokines are not fully understood. We have recently shown that IL-21 is synthesized in excess in psoriatic skin lesions and causes epidermal hyperplasia when injected intradermally in mice. Moreover, in the human psoriasis SCID mouse model, neutralization of IL-21 reduces both skin thickening and expression of inflammatory molecules, thus supporting the pathogenic role of IL-21 in psoriasis. However, the basic mechanism by which IL-21 promotes skin pathology remains unknown. In this study, we show that CD4(+) cells accumulate early in the dermis of IL-21-treated mice and mediate the development of epidermal hyperplasia. Indeed, IL-21 fails to induce skin damage in RAG1-deficient mice and CD4(+) cell-depleted wild-type mice. The majority of CD4(+) cells infiltrating the dermis of IL-21-treated mice express IFN-γ and, to a lesser extent, IL-17A. Studies in cytokine knockout mice show that IFN-γ, but not IL-17A, is necessary for IL-21-induced epidermal hyperplasia. Finally, we demonstrate that IFN-γ-producing CD4(+) cells infiltrating the human psoriatic plaque express IL-21R, and abrogation of IL-21 signals reduces IFN-γ expression in cultures of psoriatic CD4(+) cells. Data indicate that IL-21 induces an IFN-γ-dependent pathogenic response in vivo, thus contributing to elucidate a mechanism by which IL-21 sustains skin-damaging inflammation.

Living matter observations with a novel hyperspectral supercontinuum confocal microscope for VIS to near-IR reflectance spectroscopy.

A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 µm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.

Clinical Features and Response to Treatment in Elderly Subjects Affected by Hidradenitis Suppurativa: A Cohort Study.

Hidradenitis suppurativa (HS) is a chronic-relapsing inflammatory skin disease. It usually appears in the second and third decades, but a smaller proportion of patients develop late-onset HS. Geriatric HS, defined as the persistence or the development of HS after the age of 65 years, has been poorly explored. This study aimed to investigate the clinical features, treatment management and response to therapies of HS elderly subjects (≥65 years old). We designed a multicentric observational study, gathering data from seven Italian university hospitals. Demographic and clinical data of HS patients aged over 65 years were collected at baseline, week 12 and week 24. Overall, 57 elderly subjects suffering from HS were enrolled. At baseline, disease severity was predominantly moderate-to-severe, with 45.6% of patients classified as Hurley III. The gluteal phenotype was the most frequently observed; it also appeared to affect patients' quality of life more than other phenotypes. Gluteal involvement was detected in about half (49.1%) of cases and associated with severe stages of the disease. In terms of therapeutic response, Hurley III patients showed the persistency of higher values of mean IHS4, DLQI, itch- and pain-NRS scores compared to Hurley I/II. In conclusion, disease severity in this subpopulation appears high and treatment is often challenging.

The tumor suppressor activity of IKKalpha in stratified epithelia is exerted in part via the TGF-beta antiproliferative pathway.

The transforming growth factor type beta-1 (TGF-beta) signaling pathway is a major tumor suppressor during early carcinogenesis, and its growth-suppressive activity is commonly lost during early tumor progression. IkappaB kinase alpha (IKKalpha) also acts as a tumor suppressor in stratified epithelia, and its expression and nuclear localization are progressively down-regulated during malignant progression of squamous cell carcinoma (SCC) and acquisition of an invasive phenotype. A critical role for IKKalpha in TGF-beta signaling in stratified epithelia was identified recently during normal keratinocyte differentiation, and both IKKalpha and components of the TGF-beta signaling pathway are required for induction of antiproliferative Myc antagonists in such cells. We now describe that the interaction between IKKalpha and the TGF-beta signaling pathway is also important in a subset of SCCs. In SCCs that are unable to shuttle IKKalpha to the nucleus, defective TGF-beta-induced growth arrest was rescued by introduction of a constitutively nuclear IKKalpha variant. These results suggest that the tumor-suppressive activity of IKKalpha in stratified epithelia may be exerted in part via the TGF-beta signaling pathway.

Efficacy of short-term cyclosporine treatment to control psoriasis-related events during efalizumab therapy.

Efalizumab is a recombinant humanized anti-CD11a monoclonal antibody that blocks the activation, adhesion and trafficking of T cells and has been approved for the treatment of moderate-to-severe plaque psoriasis. To document management of the fluctuations in symptom control that patients with psoriasis sometimes experience during treatment, we performed a retrospective analysis of our experience using cyclosporine as an intercurrent treatment to control psoriasis-related adverse events (AEs) in 10 patients who had received continuous efalizumab therapy for 20-200 weeks prior to recurrence of symptoms. Combination therapy with cyclosporine and efalizumab was generally well tolerated and controlled the relapse effectively. There were no reports of severe AEs during combination treatment, and no clinically significant changes were noted in clinical and laboratory values. Although mild, localized psoriasis recurred in most of these patients after cyclosporine termination, no patient experienced rebound or psoriasis flare and all continued with long-term efalizumab treatment.

CXCL4 assembles DNA into liquid crystalline complexes to amplify TLR9-mediated interferon-α production in systemic sclerosis.

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by fibrosis and vasculopathy. CXCL4 represents an early serum biomarker of severe SSc and likely contributes to inflammation via chemokine signaling pathways, but the exact role of CXCL4 in SSc pathogenesis is unclear. Here, we elucidate an unanticipated mechanism for CXCL4-mediated immune amplification in SSc, in which CXCL4 organizes "self" and microbial DNA into liquid crystalline immune complexes that amplify TLR9-mediated plasmacytoid dendritic cell (pDC)-hyperactivation and interferon-α production. Surprisingly, this activity does not require CXCR3, the CXCL4 receptor. Importantly, we find that CXCL4-DNA complexes are present in vivo and correlate with type I interferon (IFN-I) in SSc blood, and that CXCL4-positive skin pDCs coexpress IFN-I-related genes. Thus, we establish a direct link between CXCL4 overexpression and the IFN-I-gene signature in SSc and outline a paradigm in which chemokines can drastically modulate innate immune receptors without being direct agonists.

Potential Role of Cytochrome c and Tryptase in Psoriasis and Psoriatic Arthritis Pathogenesis: Focus on Resistance to Apoptosis and Oxidative Stress.

Psoriasis (PsO) is an autoimmune disease characterized by keratinocyte proliferation, chronic inflammation and mast cell activation. Up to 42% of patients with PsO may present psoriatic arthritis (PsA). PsO and PsA share common pathophysiological mechanisms: keratinocytes and fibroblast-like synoviocytes are resistant to apoptosis: this is one of the mechanism facilitating their hyperplasic growth, and at joint level, the destruction of articular cartilage, and bone erosion and/or proliferation. Several clinical studies regarding diseases characterized by impairment of cell death, either due to apoptosis or necrosis, reported cytochrome c release from the mitochondria into the extracellular space and finally into the circulation. The presence of elevated cytochrome c levels in serum has been demonstrated in diseases as inflammatory arthritis, myocardial infarction and stroke, and liver diseases. Cytochrome c is a signaling molecule essential for apoptotic cell death released from mitochondria to the cytosol allowing the interaction with protease, as the apoptosis protease activation factor, which lead to the activation of factor-1 and procaspase 9. It has been demonstrated that this efflux from the mitochondria is crucial to start the intracellular signaling responsible for apoptosis, then to the activation of the inflammatory process. Another inflammatory marker, the tryptase, a trypsin-like serine protease produced by mast cells, is released during inflammation, leading to the activation of several immune cells through proteinase-activated receptor-2. In this review, we aimed at discussing the role played by cytochrome c and tryptase in PsO and PsA pathogenesis. To this purpose, we searched pathogenetic mechanisms in PUBMED database and review on oxidative stress, cytochrome c and tryptase and their potential role during inflammation in PsO and PsA. To this regard, the cytochrome c release into the extracellular space and tryptase may have a role in skin and joint inflammation.

Anti-LL37 Antibodies Are Present in Psoriatic Arthritis (PsA) Patients: New Biomarkers in PsA.

Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis. A third of psoriatic patients develop PsA via unknown mechanisms. No reliable diagnostic markers are available for PsA, or prognostic biomarkers for PsA development in psoriasis. We previously uncovered a pro-inflammatory role for cathelicidin LL37 in lesional psoriasis skin. LL37 binds nucleic acids and stimulates plasmacytoid/myeloid dendritic cells (pDC, mDCs) to secrete type I interferon (IFN-I) and pro-inflammatory factors. LL37 becomes an autoantigen for psoriatic Th1-Th17/CD8 T cells. Anti-LL37 antibodies were detected in systemic lupus erythematosus, an autoimmune disease characterized by neutrophil-extracellular-traps release (NETosis) in target organs. LL37 can be substrate of irreversible post-translational modifications, citrullination or carbamylation, linked to neutrophil activity. Here we analyzed inflammatory factors, included LL37, in PsA and psoriasis plasma and PsA synovial fluids (SF)/biopsies. We show that LL37 (as a product of infiltrating neutrophils) and autoantibodies to LL37 are elevated in PsA, but not OA SF. Anti-LL37 antibodies correlate with clinical inflammatory markers. Anti-carbamylated/citrullinated-LL37 antibodies are present in PsA SF/plasma and, at lower extent, in psoriasis plasma, but not in controls. Plasma anti-carbamylated-LL37 antibodies correlate with PsA (DAS44) but not psoriasis (PASI) disease activity. Ectopic lymphoid structures, and deposition of immunoglobulin-(Ig)G-complexes (IC) co-localizing with infiltrating neutrophils, are observed in PsA and not OA synovial tissues (ST). Activated complement (C5a, C9), GM-CSF and IFN-I are up-regulated in PsA and not OA synovia and in PsA and psoriasis plasma but not in HD. C9 and GM-CSF levels in PsA SF correlate with clinical inflammatory markers and DAS44 (C9) and with anti-carbamylated/citrullinated-LL37 antibodies (GM-CSF and IFN-I). Thus, we uncover a role for LL37 as a novel PsA autoantibody target and correlation studies suggest participation of anti-LL37 antibodies to PsA pathogenesis. Notably, plasma antibodies to carbamylated-LL37, which correlate with DAS44, suggest their use as new disease activity markers. GM-CSF and complement C5a and C9 elevation may be responsible for autoantigens release by neutrophils and their modification, fueling inflammation and autoreactivity establishment. Finally, targeting GM-CSF, C5a, C9 can be beneficial in PsA.