Superantigens in dermatology

A comparative randomized clinical trial evaluating the efficacy and safety of tacrolimus versus hydrocortisone as a topical treatment of atopic dermatitis in children

Background: Atopic dermatitis (AD) aetiology is not exactly identified, but it is characterized by pruritic skin reactions with elevation in the levels of inflammatory markers. Despite the fact that Corticosteroids are the mainstay therapy in the management of AD, they have many local and systemic adverse effects. Objective: The aim of this study is to evaluate the efficacy and safety of topical tacrolimus ointment in comparison to topical hydrocortisone cream in the management of the AD of children diagnosed with AD. Patients and Methods: This study was conducted on 200 children with AD. They were simply randomized into two groups, the tacrolimus group treated with 0.03% topical tacrolimus ointment and the hydrocortisone group treated with 1% hydrocortisone cream twice daily during the 3 weeks study period. Results: At the end of the study, both the tacrolimus and hydrocortisone groups showed a significant decline in the mean serum level of IL-10, IL-17, and IL-23 (p < 0.05) when compared to their baseline levels. However, the tacrolimus group showed a more significant decrease (p < 0.05) in the mean serum level of IL-10, IL-17, and IL-23 as compared to the hydrocortisone group [Mean differences = 1.600, 95% CI: 0.9858-2.214; 1.300, 95% CI: 1.086-1.514 and 4.200, 95% CI: 3.321-5.079]. Moreover, the median mEASI decreased similarly from 32 to 21 in the tacrolimus group and from 30 to 22 in the hydrocortisone group (p > 0.05) [Median difference = -2.000, 95% CI: -2.651 to -1.349; Median difference = 1.000, 95% CI: 0.3489-1.651]. Mild to moderate transient stinging and erythema were the main adverse effects that showed higher incidence in the tacrolimus group than in the hydrocortisone group (p < 0.05). In most cases, they resolved within 3-4 days. Besides, tacrolimus ointment did not cause skin atrophy as compared to the hydrocortisone group (p < 0.05). Conclusion: Tacrolimus ointment is more beneficial than hydrocortisone cream in managing AD in children in terms of lowering the inflammatory markers, however, there is no difference on the dermatitis severity scale. Moreover, tacrolimus is safer with a better side effect profile compared to hydrocortisone. Trial Registration: The trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT05324618).

Different aspects of severe asthma in real life: Role of Staphylococcus aureus enterotoxins and correlation to comorbidities and disease severity

BACKGROUND

Asthma, with several phenotypes and endotypes, is considered particularly suited for precision medicine. The identification of different non-invasive biomarkers may facilitate diagnosis and treatment. Recently, Staphylococcus aureus and its enterotoxins (SE) have been found to have a role in inducing persistent type 2 airway inflammation in severe asthma, but also in such comorbidities as chronic rhinosinusitis with nasal polyposis (CRSwNP).

METHODS

The aim of this retrospective study was to evaluate the prevalence of SE-IgE sensitization in a multicentric Italian cohort of severe asthmatic patients and correlate it with demographic and clinical characteristics.

RESULTS

A total of 249 patients were included in the analysis, out of which 25.3% were staphylococcal enterotoxin B (SEB)-IgE positive. We found a meaningful association between SEB-IgE and female gender, a positive association was also measured between CRS and CRSwNP. No significant association was found between SEB-IgE sensitization and atopy, the occurrence of exacerbations and corticosteroid dosages. In the SEB-IgE-positive patient, blood eosinophil count does not appear to be correlated with the severity of the disease. Patients with SEB-IgE sensitization are, on average, younger and with an earlier disease onset, thus confirming the possibility to consider SEB-IgE sensitization as an independent risk factor for developing asthma.

CONCLUSIONS

Our data confirm that the search for SE in the initial screening phase of these patients is helpful to better phenotype them, may predict the evolution of comorbidities and lead to a targeted therapeutic choice; in this point of view this represents a goal of precision medicine.

Transcriptional Heterogeneity and the Microbiome of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphomas (CTCL) presents with substantial clinical variability and transcriptional heterogeneity. In the recent years, several studies paved the way to elucidate aetiology and pathogenesis of CTCL using sequencing methods. Several T-cell subtypes were suggested as the source of disease thereby explaining clinical and transcriptional heterogeneity of CTCL entities. Several differentially expressed pathways could explain disease progression. However, exogenous triggers in the skin microenvironment also seem to affect CTCL status. Especially Staphylococcus aureus was shown to contribute to disease progression. Only little is known about the complex microbiome patterns involved in CTCL and how microbial shifts might impact this malignancy. Nevertheless, first hints indicate that the microbiome might at least in part explain transcriptional heterogeneity and that microbial approaches could serve in diagnosis and prognosis. Shaping the microbiome could be a treatment option to maintain stable disease. Here, we review current knowledge of transcriptional heterogeneity of and microbial influences on CTCL. We discuss potential benefits of microbial applications and microbial directed therapies to aid patients with CTCL burden.

Interplay Between Skin Microbiota Dysbiosis and the Host Immune System in Psoriasis: Potential Pathogenesis

Psoriasis is a multifactorial immune-mediated disease. The highly effective and eligible treatment for psoriasis is limited, for its specific pathogenesis is incompletely elucidated. Skin microbiota is a research hotspot in the pathogenesis of immune-mediated inflammatory skin diseases nowadays, and it may have significant involvement in the provocation or exacerbation of psoriasis with broadly applicable prospects. It is postulated that skin microbiota alternation may interplay with innate immunity such as antimicrobial peptides and Toll-like receptors to stimulate T-cell populations, resulting in immune cascade responses and ultimately psoriasis. Achieving a thorough understanding of its underlying pathogenesis is crucial. Herein, we discuss the potential immunopathogenesis of psoriasis from the aspect of skin microbiota in an attempt to yield insights for novel therapeutic and preventive modalities for psoriasis.

Fungal Infections among Psoriatic Patients: Etiologic Agents, Comorbidities, and Vulnerable Population

Background

Psoriasis is a chronic inflammatory disorder of the skin and joint, affecting nearly 2-3% of the general population. It is assumed that imbalance between the types of natural microflora can accelerate the onset of the disease. Some fungi can play the role of superantigens and prolong chronic inflammation in the skin of psoriatic patients. The aim of the present investigation was to identify fungal species isolated from patients with psoriasis.

Methods

From March 2016 to May 2019, 289 patients with prior diagnosis of psoriasis were included in this survey. Direct microscopy with potassium hydroxide (KOH 10%), culture, urea hydrolysis, hair perforation test, and growth on rice grains were used to identify clinical isolates, phenotypically. For molecular identification of Candida species and Malassezia species, PCR-RFLP and PCR-sequencing were used, respectively.

Results

Forty-six out of 289 psoriatic patients had fungal infections (15.9%). Dermatophytes (54.3%), Candida spp. (19.5%), Malassezia spp. (15.2%), Aspergillus spp. (6.5%), and Fusarium spp. (4.3%) were the causative agents of fungal infections. Among Malassezia and Candida species, M. restricta (10.8%) and C. glabrata (8.7%) were the most prevalent species, respectively.

Conclusion

Our findings suggested that fungal pathogens, particularly dermatophytes, may play an important role in the pathogenicity of psoriasis. Also, due to the high rate of yeast colonization in the clinical samples of psoriatic patients, concomitant use of anti-inflammatory drugs and antifungals may represent an effective therapeutic approach for better management of chronic lesions among these patients. Mycological tests should be applied to indicate the incidence of fungal diseases in psoriatic patients.

Infantile leukocytoclastic vasculitis caused by enterotoxin-producing methicillin-sensitive Staphylococcus aureus

Staphylococcus aureus infections are known to cause leukocytoclastic vasculitis (LCV). Herein, we describe a case of an 18-month-old with LCV caused by enterotoxin-producing methicillin-sensitive Staphylococcus aureus (MSSA) emanating from an unrecognized pharyngeal abscess. It is critical to consider the possibility of extracutaneous sources of MSSA infection when investigating an infant with vasculitis. Prompt diagnosis and appropriate treatment are vital in preventing potentially life-threatening complications.

Skin and sepsis: contribution of dermatology to a rapid diagnosis

In patients who develop sepsis, whether due to primary, secondary or metastatic lesions, the skin is frequently affected. However, there are unresolved aspects regarding the general clinical manifestations in the skin or the prognosis and/or therapeutic implications. The main challenge in the approach to sepsis is its early diagnosis and management. In this review, we address the sepsis-skin relationship and the potential impact of early dermatological intervention on the septic patient through ten basic questions. We found little evidence of the participation of the dermatologist in sepsis alert programs. There are early skin changes that may alert clinicians on a possible sepsis, such as skin mottling or variations in acral skin temperature. In addition, the skin is an accessible and highly cost-effective tissue for etiological studies of some forms of sepsis (e.g., meningococcal purpura) and its involvement defines the prognosis of certain patients (e.g., infective endocarditis).

Innate Lymphocyte Mechanisms in Skin Diseases

Innate lymphocyte populations are emerging as key effectors in tissue homeostasis, microbial defense, and inflammatory skin disease. The cells are evolutionarily ancient and carry conserved principles of function, which can be achieved through shared or unique specific mechanisms. Recent technological and treatment advances have provided insight into heterogeneity within and between individuals and species. Similar pathways can extend through to adaptive lymphocytes, which softens the margins with innate lymphocyte populations and allows investigation of nonredundant pathways of immunity and inflammation that might be amenable to therapeutic intervention. Here, we review advances in understanding of innate lymphocyte biology with a focus on skin disease and the roles of commensal and pathogen responses and tissue homeostasis.

Influence of silk clothing therapy in patients with atopic dermatitis

The existence of red, inflammatory, and chronic itchy condition in the skin is commonly speculated as the presence of Atopic Dermatitis (AD) in patients. The use of silk clothing as a non-pharmacological approach in the management of AD has been noticed as an effective alternative therapy; however, the evidence based on its usage is poorly served. Hence, we aim to evaluate the effectiveness of using pure silk clothing in the therapy of AD patients. The clinical trial was performed by recruiting 30 patients with AD for up to 8 weeks of observation. They were instructed to wear pure silk clothing for the whole day without any additional medication and were investigated using the AD-related questionnaires. The findings revealed a significant decrease of AD occurrence along with a great improvement of patient’s quality of life at each time point. Our investigation demonstrated that this treatment promotes good skin appearance, comfort, and remarkable improvement in the quality of life. This promising preliminary outcome warrants a further study; hence, it can be a potential non-pharmacological treatment choice for controlling the severity of AD.

Future trends in the treatment of atopic dermatitis

Atopic dermatitis (AD) is caused by complex interactions between a variety of genetic and environmental factors that contribute to the maintenance of the chronic inflammatory skin condition. Most conventional treatments have been designed for the so-called 'average patient'. In recent years however, many previously unknown details pertaining to the mechanisms of the pathogenesis of AD have been elucidated, and novel treatments based on these pathological mechanisms or on subgroup classifications have been developed. Herein, how future treatment strategies for AD can be developed is described.

Mechanisms of microbial pathogenesis and the role of the skin microbiome in psoriasis: A review

The pathogenesis of psoriasis may involve a breakdown of immune tolerance to cutaneous microorganisms. Psoriasis is associated with a higher incidence of Crohn disease and periodontitis, two diseases involving impaired tolerance and abnormal immune activation in response to intestinal and oral microbiota, respectively. In addition, guttate and chronic plaque psoriasis are associated with Streptococcus pyogenes colonization. The aim of this review is to characterize the microorganisms implicated in psoriasis by examining results of major association studies and possible mechanisms of pathogenesis. Although studies show relative increases in Streptococcus and Staphylococcus and decreases in Malassezia and Cutibacterium, they differ in methods of sampling and methods of microbial analysis. As such, no definitive associations between microbes and psoriasis have been found to date. It also remains unclear if changes in the microbiomal composition have a causal association with psoriasis or are simply a consequence of the inflammatory microenvironment. Techniques enabling strain-level analysis rather than species-level analysis of the skin microbiome are likely necessary to determine microbiomal signatures of psoriasis. Future investigations may lead to new diagnostic tests and novel treatments, such as probiotics or bacterial transplantation.

Molecular and Genomic Landscape of Peripheral T-Cell Lymphoma

Peripheral T-cell lymphoma (PTCL) is an uncommon group of lymphoma covering a diverse spectrum of entities. Little was known regarding the molecular and genomic landscapes of these diseases until recently but the knowledge is still quite spotty with many rarer types of PTCL remain largely unexplored. In this chapter, the recent findings from gene expression profiling (GEP) studies, including profiling data on microRNA, where available, will be presented with emphasis on the implication on molecular diagnosis, prognostication, and the identification of new entities (PTCL-GATA3 and PTCL-TBX21) in the PTCL-NOS group. Recent studies using next-generation sequencing have unraveled the mutational landscape in a number of PTCL entities leading to a marked improvement in the understanding of their pathogenesis and biology. While many mutations are shared among PTCL entities, the frequency varies and certain mutations are quite unique to a specific entity. For example, TET2 is often mutated but this is particularly frequent (70-80%) in angioimmunoblastic T-cell lymphoma (AITL) and IDH2 R172 mutations appear to be unique for AITL. In general, chromatin modifiers and molecular components in the CD28/T-cell receptor signaling pathways are frequently mutated. The major findings will be summarized in this chapter correlating with GEP data and clinical features where appropriate. The mutational landscape of cutaneous T-cell lymphoma, specifically on mycosis fungoides and Sezary syndrome, will also be discussed.

Changing perspectives in atopic dermatitis

Atopic dermatitis (AD) is a multifaceted disease that involves a complex interplay between the skin and the immune system. The course of the disease depends strongly on the genetic background of the patient and on yet poorly-defined environmental factors. Changes in lifestyle could be behind the dramatic rise in the prevalence of AD across continents; including hygienic conditions, food, social habits, skin microbiome or exposure to a number of allergens. Although AD typically develops in childhood and disappears after a few years, in a relatively large number of patients it continues into adulthood. Adult AD can also appear de novo but it is often underdiagnosed and its treatment can be challenging. New, highly effective drugs are being developed to manage moderate and severe forms of the disease in adults. In this review, we highlight the most recent developments in diagnostic tools, current insights into the mechanistic basis of this disease, and therapeutic innovations.

Conventional solid fermentation alters mycotoxin contents and microbial diversity analyzed by high-throughput sequencing of a Fusarium mycotoxin-contaminated diet

Fusarium mycotoxins, commonly present in corn and its derived products for animals, has caused significant economic impact on swine reproduction in the People’s Republic of China. The objective of the present study, therefore, was to evaluate changes in mycotoxin contents and microbial diversity by conventional solid fermentation of a contaminated diet. Three diets were evaluated, as follows: control group, basal diet; test group 1 (25 Toxin), basal diet in which corn and corn gluten meal were replaced with 25% mycotoxin-contaminated corn and corn gluten meal, respectively; test group 2 (50 Toxin), basal diet in which corn and corn gluten meal were replaced with 50% mycotoxin-contaminated corn and corn gluten meal, respectively. Compound strains were used for solid-state fermentation of the compound feed. Under the present experimental conditions, conventional solid fermentation altered microbial diversity, as demonstrated by high-throughput sequencing of a Fusarium mycotoxin-contaminated diet, and the content of zearalenone (ZEA) was reduced significantly. However, deleterious effects were also observed with regard to the contents of deoxynivalenol (DON) and fumonisin B1 (FUMB1). These results may have implications for animals consuming Fusarium mycotoxin-contaminated food or feed by conventional solid fermentation.

Manipulation of Innate and Adaptive Immunity by Staphylococcal Superantigens

Staphylococcal superantigens (SAgs) constitute a family of potent exotoxins secreted by Staphylococcus aureus and other select staphylococcal species. SAgs function to cross-link major histocompatibility complex (MHC) class II molecules with T cell receptors (TCRs) to stimulate the uncontrolled activation of T lymphocytes, potentially leading to severe human illnesses such as toxic shock syndrome. The ubiquity of SAgs in clinical S. aureus isolates suggests that they likely make an important contribution to the evolutionary fitness of S. aureus. Although the apparent redundancy of SAgs in S. aureus has not been explained, the high level of sequence diversity within this toxin family may allow for SAgs to recognize an assorted range of TCR and MHC class II molecules, as well as aid in the avoidance of humoral immunity. Herein, we outline the major diseases associated with the staphylococcal SAgs and how a dysregulated immune system may contribute to pathology. We then highlight recent research that considers the importance of SAgs in the pathogenesis of S. aureus infections, demonstrating that SAgs are more than simply an immunological diversion. We suggest that SAgs can act as targeted modulators that drive the immune response away from an effective response, and thus aid in S. aureus persistence.

Prevalence and Possible Role of Candida Species in Patients with Psoriasis: A Systematic Review and Meta-Analysis

Although fungal colonization is implicated in the pathogenesis of psoriasis, its prevalence remains unclear. The aim of this systematic review and meta-analysis was to provide an overview on the prevalence of Candida species in patients with psoriasis. We searched databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and http://clinicaltrials.gov) to identify studies involving subjects of any age with an established diagnosis of psoriasis and healthy controls, who were tested for carriage of Candida spp. on the skin or mucosal membranes (or saliva and stool), or presented with clinical candidiasis with microbiologically confirmed etiology. We identified nine cross-sectional studies including a total of 1038 subjects with psoriasis (psoriatics) and 669 controls. We found Candida species detection rates for psoriatics were significantly higher than those in the controls, especially in the oral mucosa milieux. These results suggest psoriasis may be one of the systemic diseases that predispose to oral Candida spp. carriage and infection.

Immunochemical assay with monoclonal antibodies for detection of staphylococcal enterotoxin H

Staphylococcal enterotoxins cause food poisoning of various degrees of severity. For milk and meat products, there is a high probability of contamination with staphylococcal enterotoxin H (SEH). In this regard specific and sensitive methods are required to be developed for its detection and monitoring. In this work, the gene seh was expressed and a preparation of recombinant toxin was obtained. Using hybridoma technology, a panel of high-affinity monoclonal antibodies (mAbs) to SEH was produced. The antibodies were characterized and shown to have no cross-reactivity towards the main staphylococcal enterotoxins (A, B, C1, D, E, G and I). Based on these mAbs, a method for specific and quantitative detection of SEH was developed in the format of sandwich enzyme immunoassay (linear range, 0.2–3 ng/ml). All the mAbs produced revealed SEH by immunoblotting. Immunochemical analysis of the culture fluids of staphylococcal isolates obtained from the milk of mastitis-infected cows by immunoblotting and sandwich enzyme immunoassay demonstrated the conformity of these methods. Using the developed method, the toxin was revealed in blood serum and liquid food products practically to 100%. From non-liquid foods, it was shown to be extracted to a maximum with a buffer of pH 4.0–4.5.

Staphylococcus aureus and Staphylococcus epidermidis strain diversity underlying pediatric atopic dermatitis

The heterogeneous course, severity, and treatment responses among patients with atopic dermatitis (AD; eczema) highlight the complexity of this multifactorial disease. Prior studies have used traditional typing methods on cultivated isolates or sequenced a bacterial marker gene to study the skin microbial communities of AD patients. Shotgun metagenomic sequence analysis provides much greater resolution, elucidating multiple levels of microbial community assembly ranging from kingdom to species and strain-level diversification. We analyzed microbial temporal dynamics from a cohort of pediatric AD patients sampled throughout the disease course. Species-level investigation of AD flares showed greater Staphylococcus aureus predominance in patients with more severe disease and Staphylococcus epidermidis predominance in patients with less severe disease. At the strain level, metagenomic sequencing analyses demonstrated clonal S. aureus strains in more severe patients and heterogeneous S. epidermidis strain communities in all patients. To investigate strain-level biological effects of S. aureus, we topically colonized mice with human strains isolated from AD patients and controls. This cutaneous colonization model demonstrated S. aureus strain-specific differences in eliciting skin inflammation and immune signatures characteristic of AD patients. Specifically, S. aureus isolates from AD patients with more severe flares induced epidermal thickening and expansion of cutaneous T helper 2 (T_H2) and T_H17 cells. Integrating high-resolution sequencing, culturing, and animal models demonstrated how functional differences of staphylococcal strains may contribute to the complexity of AD disease.

Molecular analysis of immunoglobulin variable genes supports a germinal center experienced normal counterpart in primary cutaneous diffuse large B-cell lymphoma, leg-type

BACKGROUND

Immunophenotype of primary cutaneous diffuse large B-cell lymphoma, leg-type (PCLBCL-LT) suggests a germinal center-experienced B lymphocyte (BCL2+ MUM1+ BCL6+/-).

OBJECTIVES

As maturation history of B-cell is "imprinted" during B-cell development on the immunoglobulin gene sequence, we studied the structure and sequence of the variable part of the genes (IGHV, IGLV, IGKV), immunoglobulin surface expression and features of class switching in order to determine the PCLBCL-LT cell of origin.

METHODS

Clonality analysis with BIOMED2 protocol and VH leader primers was done on DNA extracted from frozen skin biopsies on retrospective samples from 14 patients. The clonal DNA IGHV sequence of the tumor was aligned and compared with the closest germline sequence and homology percentage was calculated. Superantigen binding sites were studied. Features of selection pressure were evaluated with the multinomial Lossos model.

RESULTS

A functional monoclonal sequence was observed in 14 cases as determined for IGHV (10), IGLV (2) or IGKV (3). IGV mutation rates were high (>5%) in all cases but one (median:15.5%), with superantigen binding sites conservation. Features of selection pressure were identified in 11/12 interpretable cases, more frequently negative (75%) than positive (25%). Intraclonal variation was detected in 3 of 8 tumor specimens with a low rate of mutations. Surface immunoglobulin was an IgM in 12/12 cases. FISH analysis of IGHM locus, deleted during class switching, showed heterozygous IGHM gene deletion in half of cases. The genomic PCR analysis confirmed the deletions within the switch μ region. IGV sequences were highly mutated but functional, with negative features of selection pressure suggesting one or more germinal center passage(s) with somatic hypermutation, but superantigen (SpA) binding sites conservation. Genetic features of class switch were observed, but on the non functional allele and co-existing with primary isotype IgM expression.

CONCLUSION

These data suggest that cell-of origin is germinal center experienced and superantigen driven selected B-cell, in a stage between germinal center B-cell and plasma cell.

The Pathogenetic Effect of Natural and Bacterial Toxins on Atopic Dermatitis

Atopic dermatitis (AD) is a common allergic skin disease that is associated with chronic, recurrent eczematous and pruritic lesions at the flexural folds caused by interacting factors related to environmental and immune system changes. AD results in dry skin, and immunoglobulin E-mediated allergic reactions to foods and environmental allergens. While steroids and anti-histamines temporarily relieve the symptoms of AD, the possibility of side effects from pharmacological interventions remains. Despite intensive research, the underlying mechanisms for AD have not been clarified. A study of Staphylococcus aureus (S. aureus) established the role of its toxins in the pathogenesis of AD. Approximately 90% of patients with AD experience S. aureus colonization and up to 50%–60% of the colonizing S. aureus is toxin-producing. Any damage to the protective skin barrier allows for the entry of invading allergens and pathogens that further drive the pathogenesis of AD. Some natural toxins (or their components) that have therapeutic effects on AD have been studied. In addition, recent studies on inflammasomes as one component of the innate immune system have been carried out. Additionally, studies on the close relationship between the activation of inflammasomes and toxins in AD have been reported. This review highlights the literature that discusses the pathogenesis of AD, the role of toxins in AD, and the positive and negative effects of toxins on AD. Lastly, suggestions are made regarding the role of inflammasomes in AD.

The immunopathogenesis of staphylococcal skin infections - A review

Staphylococcus aureus and S. pseudintermedius are the major causes of bacterial skin disease in humans and dogs. These organisms can exist as commensals on the skin, but they can also cause severe or even devastating infections. The immune system has evolved mechanisms to deal with pathogenic microorganisms and has strategies to combat bacteria of this type. What emerges is a delicate "peace" between the opposing sides, but this balance can be disrupted leading to a full blown "war". In the ferocious battle that ensues, both sides attempt to get the upper hand, using strategies that are comparable to those used by modern day armies. In this review article, the complex interactions between the immune system and the organisms are described using such military analogies. The process is described in a sequential manner, starting with the invasion itself, and progressing to the eventual battlezone in which there are heavy casualties on both sides. By the end, the appearance of a simple pustule on the skin surface will take on a whole new meaning.

The role of bacterial infection in the pathogenesis of psoriasis

The article presents the results of numerous studies confirming the involvement of bacterial agents in the psoriatic process manifestation as triggering factors. The article discusses potential pathogenic mechanisms of the participation of bacterial superantigens in the initiation of a cascade of immunological reactions resulting in the hyperproliferation of keratinocytes. The expediency of using antibacterial agents as a part of a complex therapy of different forms of the disease is discussed.

Current knowledge on psoriasis and autoimmune diseases

Psoriasis is a prevalent, chronic inflammatory disease of the skin, mediated by crosstalk between epidermal keratinocytes, dermal vascular cells, and immunocytes such as antigen presenting cells (APCs) and T cells. Exclusive cellular “responsibility” for the induction and maintenance of psoriatic plaques has not been clearly defined. Increased proliferation of keratinocytes and endothelial cells in conjunction with APC/T cell/monocyte/macrophage inflammation leads to the distinct epidermal and vascular hyperplasia that is characteristic of lesional psoriatic skin. Despite the identification of numerous susceptibility loci, no single genetic determinant has been identified as responsible for the induction of psoriasis. Thus, numerous other triggers of disease, such as environmental, microbial and complex cellular interactions must also be considered as participants in the development of this multifactorial disease. Recent advances in therapeutics, especially systemic so-called “biologics” have provided new hope for identifying the critical cellular targets that drive psoriasis pathogenesis. Recent recognition of the numerous co-morbidities and other autoimmune disorders associated with psoriasis, including inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus suggest common signaling elements and cellular mediators may direct disease pathogenesis. In this review, we discuss common cellular pathways and participants that mediate psoriasis and other autoimmune disorders that share these cellular signaling pathways.

Microbiome and pediatric atopic dermatitis

Atopic dermatitis is a chronic inflammatory skin condition with drastic impacts on pediatric health. The pathogenesis of this common disease is not well understood, and the complex role of the skin microbiome in the pathogenesis and progression of atopic dermatitis is being elucidated. Skin commensal organisms promote normal immune system functions and prevent the colonization of pathogens. Alterations in the skin microbiome may lead to increased Staphylococcus aureus colonization and atopic dermatitis progression. Despite the evidence for their important role, probiotics have not been deemed efficacious for the treatment of atopic dermatitis, although studies suggest that probiotics may be effective at preventing the development of atopic dermatitis when given to young infants. This review will cover the most recent published work on the microbiome and pediatric atopic dermatitis.

Evaluation of candidal colonization and specific humoral responses against Candida albicans in patients with psoriasis

BACKGROUND

Psoriasis is an inflammatory skin disease that can considerably affect a patient's quality of life. Environmental and genetic factors, as well as superantigens and toxins from Candida species, may play various roles in the exacerbation and persistence of psoriasis. In the present study, we evaluated candidal colonization and specific humoral responses against Candida albicans in patients with psoriasis.

METHODS

A total of 100 patients with psoriasis vulgaris and 50 healthy control individuals were enrolled in the study. Skin and oral specimens from all participants were cultured on CHROMagar Candida medium. Isolated yeast-like fungi were identified using the sequence of the D1/D2 domain of the 26S rRNA gene. Enzyme-linked immunosorbent assays (ELISAs) were used to detect immunoglobulin M (IgM), IgA, and IgG antibodies against C. albicans in sera of patients and healthy individuals.

RESULTS

Candida species were isolated from the skin of 15% of patients and 4% of controls and from oral specimens of 60% of patients and 20% of controls. There was a significant difference in candidal colonization between patients and controls (P < 0.05). Serum IgM, IgA, and IgG levels against C. albicans were significantly lower in patients with psoriasis than in controls (P < 0.05). There was no significant association between serum levels of specific antibodies against C. albicans or the frequency of candidal colonization with the clinical severity of the disease (P > 0.05).

CONCLUSIONS

The results of the present study show a higher rate of candidal colonization in patients with psoriasis in comparison with controls and a reduction in humoral immune responses in patients.

Topical tacrolimus for atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) (or atopic eczema) is a chronic inflammatory skin condition that affects children and adults and has an important impact on quality of life. Topical corticosteroids (TCS) are the first-line therapy for this condition; however, they can be associated with significant adverse effects when used chronically. Tacrolimus ointment (in its 2 manufactured strengths of 0.1% and 0.03%) might be an alternative treatment. Tacrolimus, together with pimecrolimus, are drugs called topical calcineurin inhibitors (TCIs).

OBJECTIVES

To assess the efficacy and safety of topical tacrolimus for moderate and severe atopic dermatitis compared with other active treatments.

SEARCH METHODS

We searched the following databases up to 3 June 2015: the Cochrane Skin Group Specialised Register, CENTRAL in the Cochrane Library (Issue 5, 2015), MEDLINE (from 1946), EMBASE (from 1974), LILACS (from 1982), and the Global Resource of Eczema Trials (GREAT database). We searched six trials registers and checked the bibliographies of included studies for further references to relevant trials. We contacted specialists in the field for unpublished data.A separate search for adverse effects of topical tacrolimus was undertaken in MEDLINE and EMBASE on 30 July 2013. We also scrutinised the U.S. Food and Drug Administration (FDA) websites for adverse effects information.

SELECTION CRITERIA

All randomised controlled trials (RCTs) of participants with moderate to severe atopic dermatitis (both children and adults) using topical tacrolimus at any dose, course duration, and follow-up time compared with other active treatments.

DATA COLLECTION AND ANALYSIS

Two authors independently screened and examined the full text of selected studies for compliance with eligibility criteria, risk of bias, and data extraction. Our three prespecified primary outcomes were physician's assessment, participant's self-assessment of improvement, and adverse effects. Our secondary outcomes included assessment of improvement of the disease by validated or objective measures, such as SCORAD (SCORing Atopic Dermatitis), the EASI (Eczema Area and Severity Index), and BSA (Body Surface Area) scores.

MAIN RESULTS

We included 20 studies, with 5885 participants. The variability of drug doses, outcomes, and follow-up periods made it difficult to carry out meta-analyses.A single trial showed that tacrolimus 0.1% was better than low-potency TCS by the physician's assessment (risk ratio (RR) 3.09, 95% confidence interval (CI) 2.14 to 4.45, 1 study, n = 371, moderate-quality evidence). It was also marginally better than low-potency TCS on face and neck areas and moderate-potency TCS on the trunk and extremities by the physician's assessment (RR 1.32, 95% CI 1.17 to 1.49, 1 study, n = 972, moderate level of evidence) and for some of the secondary outcomes. Compared with pimecrolimus 1%, people treated with tacrolimus were almost twice as likely to improve by the physician's assessment (RR 1.80, 95% CI 1.34 to 2.42, 2 studies, n = 506, moderate quality of evidence). Compared with the lower concentration of 0.03%, the tacrolimus 0.1% formulation reduced the risk of not having an improvement by 18% as evaluated by the physician's assessment (RR 0.82, 95% CI 0.72 to 0.92, 6 studies, n = 1640, high-quality evidence). Tacrolimus 0.1% compared with moderate-to-potent TCS showed no difference by the physician's assessment, and 2 secondary outcomes (1 study, 377 participants) and a marginal benefit favouring tacrolimus 0.1% was found by the participant's assessment (RR 1.21, 95% CI 1.13 to 1.29, 1 study, n = 974, low quality of evidence) and SCORAD.Based on data from 2 trials, tacrolimus 0.03% was superior to mild TCS for the physician's assessment (RR 2.58, 95% CI 1.96 to 3.38, 2 studies, n = 790, moderate-quality evidence) and the participant's self-assessment (RR 1.64, 95% CI 1.41 to 1.90, 1 study, n = 416, moderate quality of evidence). One trial showed moderate benefit of tacrolimus 0.03% compared with pimecrolimus 1% on the physician's assessment (RR 1.42, 95% CI 1.02 to 1.98, 1 study, n = 139, low-quality evidence), but the effects were equivocal when evaluating BSA. In the comparison of tacrolimus 0.03% with moderate-to-potent corticosteroids, no difference was found in most of the outcomes measured (including physician's and participant's assessment and also for the secondary outcomes), but in two studies, a marginal benefit favouring the corticosteroid group was found for the EASI and BSA scores.Burning was more frequent in those using calcineurin inhibitors than those using corticosteroid tacrolimus 0.03% (RR 2.48, 95% CI 1.96 to 3.14, 5 studies, 1883 participants, high-quality evidence), but no difference was found for skin infections. Symptoms observed were mild and transient. The comparison between the two calcineurin inhibitors (pimecrolimus and tacrolimus) showed the same overall incidence of adverse events, but with a small difference in the frequency of local effects.Serious adverse events were rare; occurred in both the tacrolimus and corticosteroid groups; and in most cases, were considered to be unrelated to the treatment. No cases of lymphoma were noted in the included studies nor in the non-comparative studies. Cases were only noted in spontaneous reports, cohorts, and case-control studies. Systemic absorption was rarely detectable, only in low levels, and this decreased with time. Exception is made for diseases with severe barrier defects, such as Netherton's syndrome, lamellar ichthyosis, and a few others, with case reports of a higher absorption. We evaluated clinical trials; case reports; and in vivo, in vitro, and animal studies; and didn't find any evidence that topical tacrolimus could cause skin atrophy.

AUTHORS' CONCLUSIONS

Tacrolimus 0.1% was better than low-potency corticosteroids, pimecrolimus 1%, and tacrolimus 0.03%. Results were equivocal when comparing both dose formulations to moderate-to-potent corticosteroids. Tacrolimus 0.03% was superior to mild corticosteroids and pimecrolimus. Both tacrolimus formulations seemed to be safe, and no evidence was found to support the possible increased risk of malignancies or skin atrophy with their use. The reliability and strength of the evidence was limited by the lack of data; thus, findings of this review should be interpreted with caution. We did not evaluate costs.

Superantigenic Yersinia pseudotuberculosis induces the expression of granzymes and perforin by CD4+ T cells

Bacterial superantigens (SAgs) are immunostimulatory toxins that induce acute diseases mainly through the massive release of inflammatory cytokines. Yersinia pseudotuberculosis is the only Gram-negative bacterium known to produce a SAg (Y. pseudotuberculosis-derived mitogen [YPM]). This SAg binds major histocompatibility complex class II molecules on antigen-presenting cells and T cell receptors (TcR) bearing the variable region Vβ3, Vβ9, Vβ13.1, or Vβ13.2 (in humans) and Vβ7 or Vβ8 (in mice). We have previously shown that YPM exacerbates the virulence of Y. pseudotuberculosis in mice. With a view to understanding the mechanism of YPM's toxicity, we compared the immune response in BALB/c mice infected with a YPM-producing Y. pseudotuberculosis or the corresponding isogenic, SAg-deficient mutant. Five days after infection, we observed strong CD4(+) Vβ7(+) T cell expansion and marked interleukin-4 (IL-4) production in mice inoculated with SAg-producing Y. pseudotuberculosis. These phenomena were correlated with the activation of ypm gene transcription in liver and spleen. A transcriptomic analysis revealed that the presence of YPM also increased expression of granzyme and perforin genes in the host's liver and spleen. This expression was attributed to a CD4(+) T cell subset, rather than to natural killer T (NKT) cells that display a TcR with a Vβ region that is potentially recognized by YPM. Increased production of cytotoxic molecules was correlated with hepatotoxicity, as demonstrated by an increase in plasma alanine aminotransferase activity. Our results demonstrate that YPM activates a potentially hepatotoxic CD4(+) T cell population.

Clinical features of elderly chronic urticaria

BACKGROUND/AIMS

Chronic urticaria (CU) is defined as itchy wheals lasting 6 weeks or more. As the aged population increases worldwide, it is essential to identify the specific features of this disease in the elderly population.

METHODS

We investigated the prevalence and clinical features of CU in elderly patients. Medical records of 837 CU patients from the outpatient Allergy Clinic of Ajou University Hospital, Korea were analyzed retrospectively. Patients with chronic spontaneous urticaria according to the EAACI/GA2LEN/EDF/WAO guidelines were included. Patients older than 60 years were defined as elderly.

RESULTS

Of the 837 patients, 37 (4.5%) were elderly. In elderly versus nonelderly CU patients, the prevalence of atopic dermatitis (AD) was significantly higher (37.8% vs. 21.7%, respectively; p = 0.022), while that of aspirin intolerance was lower (18.9% vs. 43.6%, respectively; p = 0.003) in terms of comorbid conditions. The prevalences of serum specific immunoglobulin E antibodies to staphylococcal enterotoxin A and staphylococcal enterotoxin B were considerably higher in elderly CU patients with AD than in those without AD (37.5% vs. 0%, respectively).

CONCLUSIONS

Elderly patients with CU had a higher prevalence of AD. Therefore, there is a need to recognize the existence of AD in elderly CU patients.

Topically applied ZnO nanoparticles suppress allergen induced skin inflammation but induce vigorous IgE production in the atopic dermatitis mouse model

BACKGROUND

Metal oxide nanoparticles such as ZnO are used in sunscreens as they improve their optical properties against the UV-light that causes dermal damage and skin cancer. However, the hazardous properties of the particles used as UV-filters in the sunscreens and applied to the skin have remained uncharacterized.

METHODS

Here we investigated whether different sized ZnO particles would be able to penetrate injured skin and injured allergic skin in the mouse atopic dermatitis model after repeated topical application of ZnO particles. Nano-sized ZnO (nZnO) and bulk-sized ZnO (bZnO) were applied to mechanically damaged mouse skin with or without allergen/superantigen sensitization. Allergen/superantigen sensitization evokes local inflammation and allergy in the skin and is used as a disease model of atopic dermatitis (AD).

RESULTS

Our results demonstrate that only nZnO is able to reach into the deep layers of the allergic skin whereas bZnO stays in the upper layers of both damaged and allergic skin. In addition, both types of particles diminish the local skin inflammation induced in the mouse model of AD; however, nZnO has a higher potential to suppress the local effects. In addition, especially nZnO induces systemic production of IgE antibodies, evidence of allergy promoting adjuvant properties for topically applied nZnO.

CONCLUSIONS

These results provide new hazard characterization data about the metal oxide nanoparticles commonly used in cosmetic products and provide new insights into the dermal exposure and hazard assessment of these materials in injured skin.

Malignant T cells secrete galectins and induce epidermal hyperproliferation and disorganized stratification in a skin model of cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) are the most common primary skin lymphomas, which are characterized by an accumulation of malignant T cells in the skin. The early lesion resembles both clinically and histologically benign inflammatory disorders and also presents with hyperproliferative epidermis and T-cell infiltration. Despite considerable progress in understanding the molecular mechanisms involved in the malignant transformation of T cells, the causes of the morphological and histopathological features of the disease are largely unknown. We used an organotypic model of CTCL to show that malignant T cells through the secretion of galectin-1 and -3 stimulate vigorous growth of keratinocytes. In parallel, malignant T cells induce disorganized keratinocyte stratification, resembling the early hyperproliferative stage of CTCL. We also observed a loss of attachment between the epithelial and mesenchymal compartments. In addition, hyperproliferation was followed by a downregulation of differentiation markers, such as keratin 10 and involucrin, and a decrease in barrier formation. In conclusion, we provide evidence that malignant T cells orchestrate the histopathological epidermal changes seen in CTCL.

Staphylococcal enterotoxins stimulate lymphoma-associated immune dysregulation

Patients with cutaneous T-cell lymphoma (CTCL) are frequently colonized with Staphylococcus aureus (SA). Eradication of SA is, importantly, associated with significant clinical improvement, suggesting that SA promotes the disease activity, but the underlying mechanisms remain poorly characterized. Here, we show that SA isolates from involved skin express staphylococcal enterotoxins (SEs) that induce crosstalk between malignant and benign T cells leading to Stat3-mediated interleukin-10 (IL-10) production by the malignant T cells. The SEs did not stimulate the malignant T cells directly. Instead, SEs triggered a cascade of events involving cell-cell and asymmetric cytokine interactions between malignant and benign T cells, which stimulated the malignant T cells to express high levels of IL-10. Much evidence supports that malignant activation of the Stat3/IL-10 axis plays a key role in driving the immune dysregulation and severe immunodeficiency that characteristically develops in CTCL patients. The present findings thereby establish a novel link between SEs and immune dysregulation in CTCL, strengthening the rationale for antibiotic treatment of colonized patients with severe or progressive disease.

Soluble T cell receptor Vβ domains engineered for high-affinity binding to staphylococcal or streptococcal superantigens

Staphylococcus aureus and group A Streptococcus secrete a collection of toxins called superantigens (SAgs), so-called because they stimulate a large fraction of an individual’s T cells. One consequence of this hyperactivity is massive cytokine release leading to severe tissue inflammation and, in some cases, systemic organ failure and death. The molecular basis of action involves the binding of the SAg to both a T cell receptor (TCR) on a T cell and a class II product of the major histocompatibility complex (MHC) on an antigen presenting cell. This cross-linking leads to aggregation of the TCR complex and signaling. A common feature of SAgs is that they bind with relatively low affinity to the variable region (V) of the beta chain of the TCR. Despite this low affinity binding, SAgs are very potent, as each T cell requires only a small fraction of their receptors to be bound in order to trigger cytokine release. To develop high-affinity agents that could neutralize the activity of SAgs, and facilitate the development of detection assays, soluble forms of the Vβ regions have been engineered to affinities that are up to 3 million-fold higher for the SAg. Over the past decade, six different Vβ regions against SAgs from S. aureus (SEA, SEB, SEC3, TSST-1) or S. pyogenes (SpeA and SpeC) have been engineered for high-affinity using yeast display and directed evolution. Here we review the engineering of these high-affinity Vβ proteins, structural features of the six different SAgs and the Vβ proteins, and the specific properties of the engineered Vβ regions that confer high-affinity and specificity for their SAg ligands.

A review of causes of Stevens-Johnson syndrome and toxic epidermal necrolysis in children

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare life-threatening conditions almost exclusively attributed to drugs. The incidence in children is lower than in adults and has a better outcome. Mycosplama pneumoniae infection may be involved in some cases of paediatric SJS. The main etiologic factors for both SSJ and TEN are sulphonamides and anticonvulsants, followed by penicillins and non-steroidal anti-inflammatory drugs. In rare instances, paracetamol is the only suspected drug. By contrast with adults, allopurinol, oxicams and nevirapine are not identified as causative agents in children, probably due to differences in drug prescriptions. The only aspects of treatment that have been proved to improve survival are the rapid withdrawal of the suspected offending drugs and an optimal supportive therapy with emphasis in nutritional support, accompanied by management of denuded skin areas. The use of specific therapies remains controversial.

Immunology of atopic eczema: overcoming the Th1/Th2 paradigm

Atopic eczema (AE) is a challenge for modern medicine, because it is prevalent, severely affects quality of life of patients and their families, and causes high socioeconomic costs. The pathogenesis of AE is complex. While initial studies suggested a Th2 deviation as primary reason for the disease, numerous studies addressed a genetically predetermined impaired epidermal barrier as leading cause in a subgroup of patients. Recently, immune changes beyond the initial Th2 concept were defined in AE, with a role for specialized dendritic cells as well as newly identified T helper cell subsets such as Th17 and Th22 cells. Furthermore, trigger factors are expanded beyond classical Th2 allergens such as pollen or house dust mites to microbial products as well as self-antigens. This review pieces together our current understanding of immune as well as barrier abnormalities into the pathogenesis mosaic of AE.

Expression patterns of Th1/Th2 transcription factors in patients with guttate psoriasis

Many lines of evidence propose that psoriasis is a T cell-mediated disease where T cell activation is followed by secretion of inflammatory cytokines. To elucidate the functional state of T cells in guttate psoriasis, we analysed mRNA expression levels of T-bet and GATA-3 for Th1 and Th2 differentiation, respectively together with Th1 (IFN-γ) and Th2 (IL-4) cytokine mRNA expression. Relative quantification of T-bet, GATA-3, IFN-γ and Th2, and IL-4 transcripts in peripheral blood leukocytes (PBL) was conducted by real-time reverse transcriptase PCR (RT-PCR). Serum levels of IFN-γ and Th2 and IL-4 were also determined by ELISA. GATA-3 and IL-4 mRNA expression levels were lower in psoriatic patients as compared to normal healthy controls. The expression levels of T-bet and IFN-γ and Th2 genes were relatively similar in the patients and controls. In addition, a marked decrease in plasma IL-4 levels was observed in the psoriasis group, while no differences were observed with regard to levels of IFN-γ and Th2 between patients and normal subjects. Furthermore, a clear correlation between decreased IL-4 mRNA expression and IL-4 (P < 0.05) was revealed. These results suggested that altered balance between Th1 and Th2 cells transcription factor genes and they products may be implicated in the pathogenesis of psoriasis.

Engineering a soluble high-affinity receptor domain that neutralizes staphylococcal enterotoxin C in rabbit models of disease

Superantigens (SAgs) are a class of immunostimulatory exotoxins that activate large numbers of T cells, leading to overproduction of cytokines and subsequent inflammatory reactions and systemic toxicity. Staphylococcal enterotoxin C (SEC), a SAg secreted by Staphylococcus aureus, has been implicated in various illnesses including non-menstrual toxic shock syndrome (TSS) and necrotizing pneumonia. SEC has been shown to cause TSS illness in rabbits and the toxin contributes to lethality associated with methicillin-resistant S.aureus (MRSA) in a rabbit model of pneumonia. With the goal of reducing morbidity and mortality associated with SEC, a high-affinity variant of the extracellular variable domain of the T-cell receptor beta-chain for SEC (~14 kDa) was generated by directed evolution using yeast display. This protein was characterized biochemically and shown to cross-react with the homologous (65% identical) SAg staphylococcal enterotoxin B (SEB). The soluble, high-affinity T-cell receptor protein neutralized SEC and SEB in vitro and also significantly reduced the bacterial burden of an SEC-positive strain of MRSA (USA400 MW2) in an infective endocarditis model. The neutralizing agent also prevented lethality due to MW2 in a necrotizing pneumonia rabbit model. These studies characterize a soluble high-affinity neutralizing agent against SEC, which is cross-reactive with SEB, and that has potential to be used intravenously with antibiotics to manage staphylococcal diseases that involve these SAgs.

Toxic shock syndrome in two dogs

Two young, unrelated, spayed female Labrador retrievers were evaluated for severe, diffuse, generalized erythema and edema of the skin. Both dogs exhibited signs of disseminated intravascular coagulopathy and were euthanized. On postmortem examination, toxic shock syndrome (TSS) was diagnosed based on histopathology and supported by skin cultures. TSS is a rarely reported disease in veterinary medicine and can cause acute and profound clinical signs. Rapid recognition of this disease process and immediate treatment may improve the clinical outcome.

Allergic skin disease

The two most common allergic skin diseases in the world are often the least familiar to practicing surgeons: atopic dermatitis and contact dermatitis. When unrecognized, these disorders can cause great discomfort and decreased quality of life. This is only made worse by a surgical procedure which can exacerbate the disease process. Through proper recognition, management, and peri-surgical prophylaxis flares of these diseases can be avoided, leading to decreased morbidity and improved patient satisfaction. This article summarizes the pathophysiology and management of both atopic and contact dermatitis, with attention to implications for the surgeon.

[Recurrent toxin-mediated perineal erythema in an 11-year-old child]

INTRODUCTION

Recurrent perineal erythema is a rare toxin-mediated disease. We report the case of recurrent toxin-mediated perineal erythema in a child.

CASE REPORT

An 11-year-old boy was hospitalized for erythematous pustular eruption involving the perineum and the axillary area. This erythema started a few days after the onset of pharyngotonsillitis and the patient's personal history involved another episode of pharyngotonsillitis which was followed by an identical cutaneous eruption. Laboratory analysis confirmed the diagnosis of recurrent toxin-mediated perineal erythema. The skin disorder quickly improved and antistreptococcal antibiotic treatment was initiated to eradicate bacteria.

DISCUSSION

Recurrent toxin-mediated perineal erythema is a cutaneous disease mediated by superantigens which are toxins produced by staphylococci and streptococci. It is characterized by recurrent macular erythema involving the perineum. Streptococcus pyogenes is the most common cause of recurrent toxin-mediated perineal erythema, with Staphylococcus aureus being isolated most rarely. This observation emphasizes the possibility of atypical clinical presentation with pustular lesions, and dermatologists must be mindful of this aetiology in order to isolate bacterial toxins and to initiate appropriate antibiotics.

Kawasaki disease: laboratory findings and an immunopathogenesis on the premise of a "protein homeostasis system"

Kawasaki disease (KD) is a self-limited systemic inflammatory illness, and coronary artery lesions (CALs) are a major complication determining the prognosis of the disease. Epidemiologic studies in Asian children suggest that the etiologic agent(s) of KD may be associated with environmental changes. Laboratory findings are useful for the diagnosis of incomplete KD, and they can guide the next-step in treatment of initial intravenous immunoglobulin non-responders. CALs seem to develop in the early stages of the disease before a peak in inflammation. Therefore early treatment, before the peak in inflammation, is mandatory to reduce the risk of CAL progression and severity of CALs. The immunopathogenesis of KD is more likely that of acute rheumatic fever than scarlet fever. A hypothetical pathogenesis of KD is proposed under the premise of a "protein homeostasis system"; where innate and adaptive immune cells control pathogenic proteins that are toxic to host cells at a molecular level. After an infection of unknown KD pathogen(s), the pathogenic proteins produced from an unknown focus, spread and bind to endothelial cells of coronary arteries as main target cells. To control the action of pathogenic proteins and/or substances from the injured cells, immune cells are activated. Initially, non-specific T cells and non-specific antibodies are involved in this reaction, while hyperactivated immune cells produce various cytokines, leading to a cytokine imbalance associated with further endothelial cell injury. After the emergence of specific T cells and specific antibodies against the pathogenic proteins, tissue injury ceases and a repair reaction begins with the immune cells.