COVID-19 prophylaxis, diagnostics, and treatment in patients with rheumatic diseases. The Polish experts panel opinion.

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolves, infection management in vulnerable populations requires formalized guidance. Although low-virulence variants of SARS-CoV-2 remain predominant, they pose an increased risk of severe illness in adults with rheumatic and musculoskeletal diseases (RMDs). Several disease-specific (chronic long-grade inflammation, concomitant immunosuppression) and individual (advanced age, multimorbidity, pregnancy, vaccination status) factors contribute to excess risk in RMD populations. Various post-COVID-19 manifestations are also increasingly reported and appear more commonly than in the general population. At a pathogenetic level, complex interplay involving innate and acquired immune dysregulation, viral persistence, and genetic predisposition shapes a unique susceptibility profile. Moreover, incident cases of SARS-CoV-2 infection as a trigger factor for the development of autoimmune conditions have been reported. Vaccination remains a key preventive strategy, and encouraging active education and awareness will be crucial for rheumatologists in the upcoming years. In patients with RMDs, COVID-19 vaccines' benefits outweigh the risks. Derivation of specialized diagnostic and therapeutic protocols within a comprehensive COVID-19 care plan represents an ideal scenario for healthcare system organization. Vigilance for symptoms of infection and rapid diagnosis are key for introducing antiviral treatment in patients with RMDs in a timely manner. This review provides updated guidance on optimal immunization, diagnosis, and antiviral treatment strategies.

Acute Heart Failure in the Course of Macrophage Activation Syndrome Due to Newly Diagnosed Systemic Lupus Erythematosus: Case Presentation and Literature Review.

Macrophage activation syndrome is an uncommon yet dangerous and potentially fatal complication of many rheumatic diseases, inducing multiple organ failure, including, although rarely, acute heart failure. In the following paper, we present a case of a 37-year-old woman who, in a short period of time after a gynecological procedure due to fetal death, developed full-blown lupus erythematosus leading to early stages of macrophage activation syndrome with acute heart failure as its main clinical manifestation. We also include herein a brief literature review of the current understanding of diverse macrophage populations and their functions in various organs (focusing especially on the heart muscle), as well as a summary of different attempts at composing concise criteria for diagnosing macrophage activation syndrome.

The Role of Sclerostin in Rheumatic Diseases: A Review.

Systemic connective tissue disorders constitute a heterogenous group of autoimmune diseases with the potential to affect a range of organs. Rheumatoid arthritis (RA) is a chronic, progressive, autoimmune inflammatory disease affecting the joints. Systemic lupus erythematosus (SLE) may manifest with multiple system involvement as a result of inflammatory response to autoantibodies. Spondyloarthropathies (SpAs) such as ankylosing spondylitis (AS) or psoriatic arthritis (PsA) are diseases characterised by the inflammation of spinal joints, paraspinal tissues, peripheral joints and enthesitis as well as inflammatory changes in many other systems and organs. Physiologically, sclerostin helps to maintain balance in bone tissue metabolism through the Wnt/ß-catenin pathway, which represents a major intracellular signalling pathway. This review article aims to present the current knowledge on the role of sclerostin in the Wnt/ß-catenin pathway and its correlation with clinical data from RA, SLE, AS and PsA patients.

Fatigue in Inflammatory Joint Diseases.

Fatigue is a prevalent symptom in various rheumatic diseases, such as rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. It is characterised as a subjective, enduring feeling of generalised tiredness or exhaustion, impacting the patient's life quality and exacerbating disability. The fatigue nature is multifaceted, encompassing physiological, psychological, and social factors, and although the exact cause of inflammatory joint diseases is not fully understood, several factors are believed to contribute to its development. Despite high prevalence and importance, the symptom is often underestimated in clinical practice. Chronic inflammation, commonly associated with rheumatic diseases, has been proposed as a potential contributor to fatigue development. While current treatments effectively target inflammation and reduce disease activity, fatigue remains a persistent problem. Clinical evaluation of rheumatic diseases primarily relies on objective criteria, whereas fatigue, being a subjective symptom, is solely experienced and reported by the patient. Managing fatigue in inflammatory joint diseases involves a multifaceted approach. Identifying and comprehensively assessing the subjective components of fatigue in individual patients is crucial for effectively managing this symptom in everyday clinical practice.

Copper and Zinc Particles as Regulators of Cardiovascular System Function-A Review.

Copper and zinc are micronutrients that play a crucial role in many cellular pathways, act as cofactors in enzymatic systems, and hence, modulate enzyme activity. The regulation of these elements in homeostasis is precisely controlled by various mechanisms. Superoxide dismutase (SOD) is an enzyme requiring both copper and zinc for proper functioning. Additionally, there is an interaction between the concentrations of copper and zinc. Dietary ingestion of large amounts of zinc augments intestinal absorption of this trace element, resulting in copper deficiency secondary to zinc excess. The presence of an overabundance of copper and zinc has a detrimental impact on the cardiovascular system; however, the impact on vascular contractility varies. Copper plays a role in the modulation of vascular remodeling in the cardiac tissue, and the phenomenon of cuproptosis has been linked to the pathogenesis of coronary artery disease. The presence of copper has an observable effect on the vasorelaxation mediated by nitric oxide. The maintenance of proper levels of zinc within an organism influences SOD and is essential in the pathogenesis of myocardial ischemia/reperfusion injury. Recently, the effects of metal nanoparticles have been investigated due to their unique characteristics. On the other hand, dietary introduction of metal nanoparticles may result in vascular dysfunction, oxidative stress, and cellular DNA damage. Copper and zinc intake affect cardiovascular function, but more research is needed.

Aseptic Abscess Syndrome in Rheumatoid Arthritis Patient.

Aseptic abscess syndrome (AAS) is a rare, potentially life-threatening disorder, with numerous features of neutrophilic dermatoses. The main symptoms include aseptic abscess-like collections in internal organs (spleen, liver, lungs), lack of microbes (bacteria, viruses, or parasites) after an exhaustive search, ineffectiveness of antibiotics, and high sensitivity to corticosteroid therapy. AAS is characterized by the development of deep, inflammatory abscesses and systemic symptoms (weight loss, abdominal pain, fever, and leukocytosis). They may be associated with inflammatory bowel disease (IBD) and autoimmune diseases. The patient in this study is a 67-year-old man, suffering from rheumatoid arthritis (RA), with numerous purulent abscesses in the mediastinum, within the subcutaneous tissue above the extension surfaces of the joints, and on the dorsum of the hands. The lesions are accompanied by bone destruction. The patient was treated with prednisone 40 mg and adalimumab, which resulted in a quick reduction of inflammatory markers and clinical improvement, as well as the healing and absorption of abscesses. Despite COVID-19 infection, treatment with remdesivir, prednisone, and adalimumab was continued, with the complete resolution of the lesions. AAS is difficult to recognize, so practitioners have to be aware of this condition, especially in patients with RA.

Fatal Acute Heart Failure in the Course of Macrophage Activation Syndrome: Case Report and Literature Review.

Macrophage activation syndrome is a severe and potentially fatal condition in rheumatology. It can involve many different organs and systems, including the cardiovascular system, but heart failure due to its course is a relatively rare occurrence. In the following paper, we present a case of a young woman with newly diagnosed systemic lupus erythematosus who, in the span of two months, developed macrophage activation syndrome and acute heart failure, which caused her death. We analyze potential causes that may have led to that outcome, and present a brief review of the current literature concerning different macrophage groups in the heart and their potential involvement in the development of heart failure.

Usefulness of Ultrasound Examination in the Assessment of the Nail Apparatus in Psoriasis.

The assessment of psoriatic nail changes in everyday practice is based exclusively on clinical symptoms that do not reflect the entire disease process in the nail apparatus. The use of imaging methods, especially widely available and inexpensive ultrasonography, creates the possibility of additional revealing and assessing grayscale of morphological changes of the ventral nail plate, nail bed, and matrix, as well as the attachment of the finger extensor tendon to the distal phalanx. What is more, it enables the assessment of inflammation severity in the power Doppler technique. A qualitative classification of nail plate morphological changes corresponding to the severity of psoriatic nail changes has been developed so far and attempts are being made to develop a quantitative method to assess not only the presence of changes but also the severity of inflammation. Nail ultrasonography is not commonly performed, although published studies indicate the possible use of this technique in the assessment of psoriatic changes in nail structures. It can be particularly useful in subclinical changes imaging, preceding clinical manifestation of psoriatic nail changes, enthesopathy: subclinical and in the course of psoriatic arthritis, as well as in the assessment of treatment efficacy. This review article aims to summaries the research on ultrasonography of the nail apparatus which has been carried out so far, taking into account its applicability in clinical practice.

The effect of therapy on TRM in psoriatic lesions.

Introduction: The course of psoriasis is associated with recurrence of the lesions at the same location despite effective treatment. It is due to the presence of TRM (tissue-resident memory cells) in the seemingly healthy skin, which may initiate an inflammatory cascade. Aim: The assessment of TRM in psoriatic lesions prior to and after 12 weeks of systemic therapy with methotrexate (MTX) or secukinumab (SEC) or ixekizumab (IXE) or adalimumab (ADA). Material and methods: TRM markers (CD4, CD8, CD103, CD69, CD49, CXCR6) and the tissue expression of cytokines (IL-17, IL-22) in the psoriatic lesions obtained from 13 patients compared to 10 healthy skin samples were evaluated with immunohistochemistry. Biopsy specimens were collected three times from the same psoriatic plaque before and after 4 and 12 weeks of therapy. Results: The expression of TRM markers in the lesions decreased at three time points (W0, W4, W12), revealing the diminished intensity of fluorescence over time with each therapy. The most rapid response was observed with anti-IL-17 therapy at W4 of treatment, while with MTX and ADA at W12. Conclusions: The decreased expression of TRM markers occurring predominantly in the lesional dermis and not in the epidermis over 12 weeks of observation may be due to the poorer penetration of systemic drugs to the epidermis, or the process of psoriatic lesion regression in the epidermis is secondary to the reduction of inflammation in the skin, or TRM in the epidermis may be more resistant to therapy.

Role of Distinct Macrophage Populations in the Development of Heart Failure in Macrophage Activation Syndrome.

Macrophage activation syndrome (MAS) is one of the few entities in rheumatology with the potential to quickly cause multiple organ failure and loss of life, and as such, requires urgent clinical intervention. It has a broad symptomatology, depending on the organs it affects. One especially dangerous aspect of MAS's course of illness is myocarditis leading to acute heart failure and possibly death. Research in recent years has proved that macrophages settled in different organs are not a homogenous group, with particular populations differing in both structure and function. Within the heart, we can determine two major groups, based on the presence of the C-C 2 chemokine receptor (CCR2): CCR2+ and CCR2-. There are a number of studies describing their function and the changes in the population makeup between normal conditions and different illnesses; however, to our knowledge, there has not been one touching on the matter of changes occurring in the populations of heart macrophages during MAS and their possible consequences. This review summarizes the most recent knowledge on heart macrophages, the influence of select cytokines (those particularly significant in the development of MAS) on their activity, and both the immediate and long-term consequences of changes in the makeup of specific macrophage populations-especially the loss of CCR2- cells that are responsible for regenerative processes, as well as the substitution of tissue macrophages by the highly proinflammatory CCR2+ macrophages originating from circulating monocytes. Understanding the significance of these processes may lead to new discoveries that could improve the therapeutic methods in the treatment of MAS.

Efficacy and safety of switching from reference adalimumab to CT-P17 (100 mg/ml): 52-week randomized, double-blind study in rheumatoid arthritis.

OBJECTIVE: To compare the safety and efficacy of switching from reference adalimumab to adalimumab biosimilar CT-P17 with continuing reference adalimumab/CT-P17 in active RA. METHODS: This double-blind, phase III study randomized (1:1) subjects with active RA to receive 40 mg (100 mg/ml) CT-P17 or European Union-sourced reference adalimumab subcutaneously every 2 weeks (Q2W) until week (W) 24 [treatment period (TP) 1]. Thereafter, subjects receiving reference adalimumab were randomized (1:1) to continue reference adalimumab or switch to CT-P17 from W26 (both Q2W until W48; TP2). Subjects receiving CT-P17 in TP1 continued CT-P17. W0-W24 results were previously reported; we present W26-W52 findings. End points were efficacy (including joint damage progression), pharmacokinetics, safety and immunogenicity. RESULTS: Of 607 subjects who initiated TP2 treatment, 303 continued CT-P17, 153 continued reference adalimumab and 151 switched to CT-P17. Efficacy improvements up to W24 were maintained during TP2; efficacy was comparable among groups. At W52, 20% improvement in ACR response rates were 80.5% (continued CT-P17), 77.8% (continued reference adalimumab) and 82.2% (switched to CT-P17). Joint damage progression was minimal. Mean trough serum adalimumab concentrations were similar among groups. CT-P17 and reference adalimumab safety profiles were numerically similar and switching did not affect immunogenicity. At W52, 28.4% (continued CT-P17), 27.0% (continued reference adalimumab) and 28.3% (switched to CT-P17) of subjects were anti-drug antibody-positive. CONCLUSION: Efficacy, pharmacokinetics, safety and immunogenicity of CT-P17 and reference adalimumab were comparable after 1 year of treatment, including after switching from reference adalimumab to CT-P17. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT03789292.

The Role of 20-HETE, COX, Thromboxane Receptors, and Blood Plasma Antioxidant Status in Vascular Relaxation of Copper-Nanoparticle-Fed WKY Rats.

Recently, the addition of copper nanoparticles (NPs) in a daily diet (6.5 mg/kg) was studied in different animal models as a possible alternative to ionic forms. Male Wistar-Kyoto rats (24-week-old, n = 11) were fed with copper, either in the form of carbonate salt (Cu6.5) or metal-based copper NPs (NP6.5), for 8 weeks. The third group was fed with a half dose of each (NP3.25 + Cu3.25). The thoracic aorta and blood plasma was studied. Supplementation with NP6.5 decreased the Cu (×0.7), Cu/Zn-ratio (×0.6) and catalase (CAT, ×0.7), and increased Zn (×1.2) and superoxide dismutase (SOD, ×1.4). Meanwhile, NP3.25 + Cu3.25 decreased the Cu/Zn-ratio (×0.7), and CAT (×0.7), and increased the daily feed intake (×1.06). Preincubation with either the selective cyclooxygenase (COX)-2 inhibitor, or the non-selective COX-1/2 inhibitor attenuated vasodilation of rat thoracic aorta in the NP6.5 group exclusively. However, an increased vasodilator response was observed in the NP6.5 and NP3.25 + Cu3.25 group of rats after preincubation with an inhibitor of 20-hydroxyeicosatetraenoic acid (20-HETE) formation, and the thromboxane receptor (TP) antagonist. Significant differences were observed between the NP6.5 and NP3.25 + Cu3.25 groups of rats in: dietary intake, acetylcholine-induced vasodilation, and response to COX-inhibitors. Copper NPs in a standard daily dose had more significant effects on the mechanism(s) responsible for the utilization of reactive oxygen species in the blood plasma with the participation of prostanoids derived from COX-2 in the vascular relaxation. Dietary copper NPs in both doses modified vasodilation through the vasoconstrictor 20-HETE and the TP receptors.

Ultrasound Evaluation of the Effectiveness of the Use of Acitretin in the Treatment of Nail Psoriasis.

The study aimed to evaluate the effect of retinoid treatment on the morphological changes in the nail apparatus in patients with nail psoriasis. MATERIAL AND METHODS: 41 patients aged 32 to 64 with nail psoriasis, without clinical signs of psoriatic arthritis, started on acitretin 0.6 to 0.8 mg kg b.w./d, for six months and 28 people in the control group were included in the study. Both groups had ultrasound examination of fingernails and digital extensor tendon in the distal interphalangeal joints. In psoriatic patients, US examination was conducted before starting the treatment and after six months. A total of 685 nails were examined. RESULTS: After six months of treatment, there was a reduction in the thickness of the nail bed and nail matrix (p = 0.046 and p = 0.031, respectively). The thickness of the nail plates decreased, although it was statistically insignificant (p = 0.059) and it was higher than in the control group (p = 0.034). The reduced severity of clinical nail changes after six months of retinoid treatment did not correlate with the reduction in extensor tendon thickness in any group of patients. CONCLUSIONS: In patients with nail psoriasis, acitretin treatment resulted in a rapid decrease in the thickness of the nail bed and matrix, but it did not affect the thickness of the nail plate after six months. There was no effect of acitretin on the digital extensor tendon thickness or the increased blood supply to the tendon area. The results of the study may indicate the usefulness of ultrasound nail examinations in patients with nail psoriasis not only to assess the advancement of morphological changes and response to treatment, but also to choose the potential treatment.

Efficacy and safety of biosimilar CT-P17 versus reference adalimumab in subjects with rheumatoid arthritis: 24-week results from a randomized study.

BACKGROUND: To demonstrate equivalent efficacy of the proposed high-concentration (100 mg/ml), citrate-free adalimumab biosimilar CT-P17 to European Union-approved adalimumab (EU-adalimumab) in subjects with active rheumatoid arthritis (RA). METHODS: This randomized, double-blind phase III study ( ClinicalTrials.gov , NCT03789292) randomized (1:1) subjects with active RA at 52 centers to receive CT-P17 or EU-adalimumab 40 mg subcutaneously every 2 weeks until week 52. Results to week 24 are reported here. The primary endpoint was 20% improvement by American College of Rheumatology criteria (ACR20) response rate at week 24. Equivalence was concluded if the corresponding confidence intervals (CIs) for the estimate of treatment difference were within predefined equivalence margins: - 15 to 15% (95% CI; European Medicines Agency assumption); - 12 to 15% (90% CI; Food and Drug Administration assumption). Additional efficacy, pharmacokinetic, usability, safety, and immunogenicity endpoints were evaluated. RESULTS: 648 subjects were randomized (324 CT-P17; 324 EU-adalimumab). The ACR20 response rate at week 24 was 82.7% (n = 268/324) in both groups (intention-to-treat population). The 95% CI (- 5.94 to 5.94) and 90% CI (- 4.98 to 4.98) were within predefined equivalence margins for both assumptions and equivalent efficacy was concluded. Additional endpoints and overall safety were comparable between groups. Mean trough serum concentrations of CT-P17 were slightly higher than those of EU-adalimumab. Immunogenicity was slightly lower numerically for the CT-P17 group than for the EU-adalimumab group. CONCLUSIONS: CT-P17 and EU-adalimumab have equivalent efficacy and comparable safety and immunogenicity in subjects with active RA. Overall safety of CT-P17 is consistent with the known safety profile of reference adalimumab. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03789292 . Registered 28 December 2018-retrospectively registered.

A case of mucopolysaccharidosis type VI in a polish family. Importance of genetic testing and genotype-phenotype relationship in the diagnosis of mucopolysaccharidosis.

BACKGROUND AND OBJECTIVES: Mucopolysaccharidosis type VI (MPS VI) is a rare, autosomal recessive lysosomal storage disorder caused by deficient enzymatic activity of N-acetyl galactosamine-4-sulphatase, which is caused by mutations in the arylsulphatase B (ARSB) gene. To date, 163 different types of mutations in the ARSB have been reported. However, the full mutation spectrum in the MPS VI phenotype is still not known. The aim of this study was to perform molecular testing of the ARSB gene in the patient and his family members to confirm MPS VI. METHODS: Molecular characterisation of the ARSB gene was performed using Sanger sequencing. We studied a child suspected of having MPS VI and 16 other relatives. RESULTS: We identified a C-to-T transition resulting in an exchange of the Arg codon 160 for a premature stop codon (R160*, in exon 2). The transition was in CpG dinucleotides. INTERPRETATION AND CONCLUSIONS: The study provided some insights into the genotype-phenotype relationship in MPS VI and the importance of genetic testing when diagnosing MPS, which is not a mandatory test for the diagnosis and only very occasionally performed. Additionally, we present here the history of a family with confirmed MPS VI, which is extremely rare especially in south-eastern Poland. What is more, the position where the mutation is located is very interesting because it is the region of CpG, which is the site of the methylation process. Thus, this opens the possibility of a new approach indicating the involvement of an epigenetic mechanism that should be examined in the context of the pathomechanism of MPS.

The Correction of Facial Morphea Lesions by Hyaluronic Acid: A Case Series and Literature Review.

INTRODUCTION: The aim of the study is to assess the long-term safety and efficacy of hyaluronic acid (HA) administration in correction of facial morphea lesions and to review the literature on the subject. Morphea is a chronic inflammatory disease of the connective tissue which may lead to serious deformations. The lesions located on the face particularly affect patients' quality of life and self-esteem; thus, there is a demand for safe and effective methods of treatment. CASE PRESENTATION: The paper presents three female patients aged 16, 17 and 70 with facial morphea lesions who had HA preparation Juvéderm® Voluma or Volux, Vycross® technology, Allergan, injected. One of the patients had additionally fractional ablative CO2 laser (FAL) therapy. DISCUSSION: The literature provides reports on successful use of HA, polymethylmethacrylate and poly-L-lactic acid for the correction of facial defects in localized scleroderma. HA is a natural component of the extracellular matrix and it therefore minimizes the probability of immunogenicity. The application technique also plays an important role. On the other hand, FAL therapy leads to the degradation of the abnormal collagen and the induction of normal collagen synthesis. CONCLUSIONS: HA injection and combination of HA application with FAL are minimally invasive, effective and safe therapeutic options for patients suffering from morphea.

Prevalence and severity of fatigue in psoriasis and psoriatic arthritis.

INTRODUCTION: Fatigue is an important and underrated symptom of many chronic diseases. AIM: The evaluation of incidence and severity of fatigue as well as the influence of selected factors on fatigue in patients with psoriasis and psoriatic arthritis (PsA). MATERIAL AND METHODS: The study included 60 patients with PsA, 58 patients with psoriasis and 61 persons in the control group aged 35-70 years. Assessment of fatigue was conducted using a fatigue subscale from the FACIT-F questionnaire. Severity of skin lesions and arthritis was determined with PASI and DAS28, respectively, as well as the number of painful and swollen joints, severity of pain and inflammatory markers. RESULTS: Severe fatigue occurred in 17%, 28%, and 1.6% of patients with psoriasis, PsA and the control group, respectively. Severity of fatigue was significantly higher in patients with PsA as compared to patients with psoriasis (p < 0.0001). In patients with psoriasis and PsA, it decreased along with the duration of psoriasis (r = 0.291, p < 0.05 vs. r = 0.382, p < 0.05, respectively). No significant correlation was found between the duration of PsA and fatigue. After using the linear regression model, severity of fatigue in psoriasis was correlated with the age of patients and the duration of psoriasis, while in PsA, with the duration of psoriasis, PASI, DAS28, CRP and the number of painful joints. CONCLUSIONS: The results of this study may indicate the need for routine fatigue examination among people with psoriasis and psoriatic arthritis.

Psoriasis and systemic lupus erythematosus in children - literature review based on case report.

Immune-mediated inflammatory diseases are a group of diseases characterized by generalized inflammation that results from immune dysregulation, especially involving the mechanisms of acquired immunity. These diseases may be familial, showing that genetic factors play an important role in their development. Additionally, the occurrence of one disease makes a patient prone to other diseases. However, the coexistence of systemic lupus erythematosus (SLE) and psoriasis (Ps) is very rare due to their distinct genetic determinants and mechanisms of pathogenesis. Treatment is also challenging, as medications used to treat one condition exacerbate or even trigger the symptoms of the other. This paper presents the case of a Ps patient with a family history of autoimmune diseases, who developed systemic lupus erythematosus during puberty, as well as a discussion on the coexistence of SLE and Ps in developmental age based on available literature searching for PubMed database and American College of Rheumatology and European League Against Rheumatism abstracts particularly in this subject.

Immunological Memory of Psoriatic Lesions.

The natural course of psoriasis is the appearance of new lesions in the place of previous ones, which disappeared after a successful therapy. Recent studies of psoriasis etiopathogenesis showed that after psoriatic plaques have disappeared, in healthy skin we can still find a trace of inflammation in the form of tissue resident memory cells (TRM). They are originally responsible for protection against viral and bacterial infections in non-lymphatic tissues. In psoriatic inflammation, they are characterized by heterogeneity depending on their origin. CD8+ T cells TRM are abundantly present in psoriatic epidermis, while CD4+ TRM preferentially populate the dermis. In psoriasis, epidermal CD8+ TRM cells express CLA, CCR6, CD103 and IL-23R antigen and produce IL-17A during ex vivo stimulation. However, CD4+ CD103+ TRM can also colonize the epidermis and produce IL-22 during stimulation. Besides T cells, Th22 and epidermal DCs proved that epidermal cells in healed skin were still present and functioning after several years of disease remission. It explains the clinical phenomenon of the tendency of psoriatic lesions to relapse in the same location and it allows to develop new therapeutic strategies in the future.

Cutaneous polyarteritis nodosa in a 7-year-old boy: difficulties in diagnosis.

Vasculitides are a diverse group of diseases. The potential diversity of their clinical symptoms requires the exclusion of other systemic connective tissue diseases, infectious diseases or malignancies. Due to similar clinical manifestations, comprehensive differential diagnosis is needed. This paper presents the case of a boy in whom polyarteritis nodosa, early stage of Behçet's disease or autoimmune/autoinflammatory syndrome induced by adjuvants was suspected following initial diagnostics. He was ultimately diagnosed with cutaneous polyarteritis nodosa.