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Introduction: The autoimmune hair loss condition alopecia areata (AA) exacts a substantial psychological and socioeconomic toll on patients. Biotechnology companies, dermatology clinics, and research institutions are dedicated to understanding AA pathogenesis and developing new therapeutic approaches. Despite recent efforts, many knowledge gaps persist, and multiple treatment development avenues remain unexplored., Areas Covered: This review summarizes key AA disease mechanisms, current therapeutic methods, and emerging treatments, including Janus Kinase (JAK) inhibitors. The authors determine that innovative drug discovery strategies for AA are still needed due to continued unmet medical needs and the limited efficacy of current and emerging therapeutics. For prospective AA treatment developers, the authors identify the pre-clinical disease models available, their advantages, and limitations. Further, they outline treatment development opportunities that remain largely unmapped., Expert Opinion: While recent advancements in AA therapeutics are promising, challenges remain, including the lack of consistent treatment efficacy, long-term use and safety issues, drug costs, and patient compliance. Future drug development research should focus on patient stratification utilizing robust biomarkers of AA disease activity and improved quantification of treatment response. Investigating superior modes of drug application and developing combination therapies may further improve outcomes. Spirited innovation will be needed to advance more effective treatments for AA.

Alopecia areata is a common autoimmune disorder characterized by non-scarring hair loss on the scalp or other hair-bearing surface. In recent years, Janus kinase (JAK) inhibitors have shown promise in the treatment of alopecia areata by disrupting the signaling pathways involved in immune-mediated hair follicle damage. However, some patients with alopecia areata exhibit insufficient responses to JAK inhibitors. This review aims to explore the predictive factors for poor responses to JAK inhibitors in patients with alopecia areata and to discuss alternative treatment strategies in such cases. Patients with a longer duration of the current episode and higher baseline severity are at an increased risk of inadequate JAK inhibitor responses. Oral administration rather than topical application, and extended treatment durations, correlate with a favorable response. Notably, the poor response to JAK inhibitors in alopecia areata may be related to the amount and functional depletion of regulatory T cells resulting from an augmented T helper-2-type immune response. For patients with poor responses to JAK inhibitors, treatment adjustments may include increasing the dosage, extending the treatment duration, combination therapies, or switching to alternative JAK inhibitors. For patients with atopic comorbidities or psychological problems, it is important to select corresponding treatment options to optimize patient outcomes. Further research is needed to establish more reliable predictors and improve overall patient care., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

It has been demonstrated that CXCL12 inhibits hair growth via CXCR4, and its neutralizing antibody (Ab) increases hair growth in alopecia areata (AA). However, the molecular mechanisms have not been fully elucidated. In the present study, we further prepared humanized CXCL12 Ab for AA treatment and investigated underlying molecular mechanisms using single-cell RNA sequencing. Subcutaneous injection of humanized CXCL12 Ab significantly delayed AA onset in mice, and dorsal skin was analyzed. T cells and dendritic cells/macrophages were increased in the AA model, but decreased after CXCL12 Ab treatment. Pseudobulk RNA sequencing identified 153 differentially expressed genes that were upregulated in AA model and downregulated after Ab treatment. Gene ontology analysis revealed that immune cell chemotaxis and cellular response to type II interferon were upregulated in AA model but downregulated after Ab treatment. We further identified key immune cell-related genes such as Ifng , Cd8a , Ccr5 , Ccl4 , Ccl5 , and Il21r , which were colocalized with Cxcr4 in T cells and regulated by CXCL12 Ab treatment. Notably, CD8+ T cells were significantly increased and activated via Jak/Stat pathway in the AA model but inactivated after CXCL12 Ab treatment. Collectively, these results indicate that humanized CXCL12 Ab is promising for AA treatment via immune modulatory effects., Competing Interests: Authors MZ and J-HS were employed by Epi Biotech Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 An, Zheng, Park, Park, Noh and Sung.)

Background: Nasopharyngeal Bordetella pertussis (BP) colonization is common, with about 5% of individuals having PCR evidence of subclinical BP infection on nasal swab, even in countries with high vaccination rates. BP secretes pertussis toxin (PTx). PTx is an adjuvant commonly used to induce autoimmunity in multiple animal models of human disease. Colocalization of PTx and myelin from myelinated nerves in the nasopharynx may lead to host sensitization to myelin with subsequent autoimmune pathology., Methods: C57BL/6J female adult mice were given varied doses and schedules of intranasal PTx, MOG 35-55 antigen, or controls to test whether intranasal administration of PTx and myelin oligodendrocyte peptide (MOG 35-55 ) could induce experimental autoimmune encephalomyelitis (EAE) in mice. While we observed systemic cell-mediated immunity against MOG 35-55 , we did not observe EAE. Unexpectedly, many mice developed alopecia. We systematically investigated this finding., Results: Patchy alopecia developed in 36.4% of mice with the optimized protocol. Pathology consistent with alopecia areata was confirmed histologically by documenting concomitant reduced anagen phase and increased telogen phase hair follicles (HFs) in biopsies from patches of hair loss in mice with alopecia. We also found reduced CD200 staining and increased CD3 + T cells surrounding the HFs of mice with alopecia compared to the mice without alopecia, indicating HF Immune Privilege (HFIP) collapse. Systemic immune responses were also found, with increased proportions of activated T cells and B cells, as well as MHCII + dendritic cells in peripheral blood and/or splenocytes. Finally, in mice initially exposed to intranasal MOG 35-55 and PTx in combination, but not to either agent alone, splenocytes were shown to proliferate after in vitro stimulation by MOG 35-55. Consistent with prior investigations, PTx exhibited a dose-response effect on immune cell induction and phenotype, with the lowest PTx dose failing to induce autoimmunity, the highest PTx dose suppressing autoimmunity, and intermediate doses optimizing autoimmunity., Conclusions: We propose that this is the first report of an autoimmune disease in an animal model triggered by colocalization of intranasal PTx and autoantigen. This model parallels a natural exposure and potential intranasal sensitization-to-pathology paradigm and supports the plausibility that nasopharyngeal subclinical BP colonization is a cause of alopecia areata., Competing Interests: KR and SG are employed by ILiAD Biotechnologies LLC, which is developing a vaccine for the prevention of Bordetella pertussis infection. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Author YL declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision. The authors declare that this study received funding from ILiAD Biotechnologies LLC (P00427002 to JR). The funder had the following involvement in the study: the study design and the writing of this article (review and edit)., (Copyright © 2024 Liu, Freeborn, Okeugo, Armbrister, Saleh, Fadhel Alvarez, Hoang, Park, Lindsey, Rapini, Glazer, Rubin and Rhoads.)

Previous studies have suggested that alopecia areata (AA) is an organ-specific disease characterized by loss of immune privilege of hair follicles. However, an increasing body of research indicates that it not only affects the skin but may also be accompanied by systemic inflammatory reactions. Therefore, searching for simple and easily available biomarkers to describe the underlying systemic inflammation in AA patients is of great clinical significance. Complete blood collection-based systemic inflammation biomarkers have been shown to be associated with the severity and prognosis of various skin and autoimmune diseases. They involve multiple cell lineages and can reveal different pathways of immune-inflammatory responses. The aim of this study was to investigate the level of complete blood collection-based systemic inflammation biomarkers in patients with AA, and to analyse their relationship with the disease severity. A total of 302 AA patients and 296 healthy controls were included in this study and the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), systemic immune inflammation index (SII), and white blood cell/lymphocyte ratio (WLR) were calculated. The differences in these indicators between the 2 groups were compared, and the relationship between NLR, PLR, SII, WLR, and the risk of severe AA were analysed. AA patients had higher NLR, SII, and WLR compared with healthy controls (p = 0.004, 0.002, and 0.002 respectively). PLR and SII were higher in the severe AA group compared with the mild-to-moderate AA patients (p = 0.005 and 0.011 respectively). The risk of severe AA increased with the increasing of PLR, SII, NLR, and WLR (p for trend was 0.001, 0.006, 0.022, and 0.021, respectively). The levels of systemic inflammation biomark-ers in AA patients are higher than in healthy people. NLR, PLR, SII, and WLR are risk factors for severe AA, suggesting a close association between systemic inflammation and disease occurrence in AA patients.

Background and Objectives : Alopecia areata (AA) is a tissue-specific immune-mediated disorder that affects hair follicles and the nail apparatus. Due to the collapse of hair follicle immune privilege in AA, hair loss ranges in severity from small, localized patches on the scalp to the loss of entire body hair. Although AA is of uncertain etiology, the disease has a common genetic basis with a number of other autoimmune diseases. Materials and Methods : To identify candidate genes that confer susceptibility to AA in the Jordanian population and further understand the disease background, we performed DNA genotyping using case-control samples of 152 patients and 150 healthy subjects. Results : While no significant result was observed in the ten single-nucleotide polymorphisms (SNPs), CLEC4D rs4304840 variants showed significant associations with AA development within our cohort ( p = 0.02). The strongest associations were for the codominant and recessive forms of rs4304840 ( p = 0.023 and p = 0.0061, respectively). Conclusions : These findings suggest that CLEC4D gene variants may contribute to AA pathogenesis among Jordanians. Further advanced genetic analysis and functional investigations are required to elucidate the genetic basis of the disease.

Background: Alopecia areata (AA) is a chronic autoimmune disease. Th1/Th2 and Treg/Th17 cells and their cytokines are implicated in AA, and we explored their clinical significance in AA., Methods: AA patients and healthy people (controls) were enrolled, with their Th1/Th2/Th17/Treg cell proportion changes and serum Th1 (INF-γ)/Th2 (IL-5, IL-6)/Th17 (IL-17, IL-22)/Treg (IL-35) cytokine levels assessed. AA patients were assigned into mild, moderate and severe alopecia according to Severity of Alopecia Tool (SALT). The relationship between alopecia severity and initial onset age, disease course, family/smoking/drinking history and sleep disorders was explored. Th1/Th2 and Treg/Th17 cells and their cytokine levels in AA patients with different severity levels were compared. The correlation between cytokine levels and SALT scores was analyzed using Spearman. Additionally, the changes of serum cytokine levels in inactive/active AA patients were compared., Results: AA patients differed from controls in family history/smoking history/drinking history/sleep disorders. Peripheral blood Th1/Th2/Th17 cell proportions and INF-γ/IL-5/IL-6/IL-17/IL-22 levels increased, while Treg cell proportions and IL-35 level dropped. With higher alopecia severity, the proportions of Th1, Th2 and Th17 cells increased, and Treg cell proportion decreased. AA patients with mild/moderate alopecia had significant differences in IL-17 level. Serum INF-γ, IL-5, IL-17 and IL-22 levels were elevated, and IL-35 level dropped in severe AA patients versus moderate AA patients., Conclusion: Th1/Th2/Th17 cell proportions and serum INF-γ/IL-5/IL-6/IL-17/IL-22 levels in AA patients were up-regulated, while Treg cell proportion and IL-35 level were repressed. SALT scores were positively-correlated with serum IL-5/IL-17 levels. SALT scores were negatively-correlated with serum IL-35., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Alopecia areata (AA), an immune-mediated disorder, is marked by temporary, nonscarring hair loss. The bulge area is protected from immune attacks by immune privilege; however, recent studies demonstrated immune cells infiltrating the bulge area., Objective: This study aims to investigate the immunohistochemical expression of the sex-determining region Y-box 9 (SOX9) and cluster of differentiation 34 (CD34) in AA patients as markers of hair follicle stem cells (HFSCs) and progenitor cells, respectively., Methods: Immunohistochemical staining of SOX9 and CD34 was applied on skin samples of 20 AA patients and 20 healthy controls., Results: SOX9 and CD34 were significantly lower in lesional samples of cases compared to perilesional and control skin biopsies. Furthermore, SOX9 level was negatively correlated with the severity of alopecia tool score (SALT score) among the studied AA patients. Moreover, lowered SOX9 expression was present in patients with recurrent attacks., Conclusions: The significant reduction of stem cell markers (SOX9 and CD34) in our studied AA cases signifies the pathological affection of HFSCs and their progeny in AA. This is thought to cause a loss of competence in generating new hair in some AA cases, which needs to be validated in further research., Limitations of the Study: This study has a small sample size.

Introduction: The development of certain immune-mediated diseases (IMD) in patients with inflammatory bowel diseases [IBD; Crohn's disease (CD), ulcerative colitis (UC)] has been linked to treatment of IBD. Hair loss in some patients may be due to immune-mediated alopecia areata (AA). Risk factors and outcomes of AA in patients with IBD have not been previously explored., Methods: This was a retrospective, multi-center case-control study. Cases were identified as individuals who developed IBD before AA diagnosis. Controls comprised of those who were never diagnosed with AA and treated contemporaneously, selected using random number generator. We extracted demographic and IBD treatment history. Severity of Alopecia Tool (SALT) was used to stratify AA severity. AA outcomes and interventions were compared within controls., Results: We identified 58 cases and 90 controls. Cases had significantly higher rate of tumor necrosis factor α antagonist (anti-TNF) use compared to controls (40.7% vs. 20.0%, p = 0.006). Both groups had similar IBD disease location, behavior, and related surgery. Majority of cases had endoscopic remission or mild disease activity at AA diagnosis. There was no difference in partial or complete improvement of AA between those who stopped or continued IBD therapy (p = 0.57). Those with severe AA were significantly less likely to have complete (0% vs 33.3%, p = 0.01) or any improvement (50% vs 84.9%, p = 0.02) of AA compared to those with non-severe AA., Discussion: Individuals with IBD who later develop AA were more likely to have been on anti-TNF at time of AA onset. Severity of AA was a significant predictor of AA resolution. Fortunately many patients had improvement in their AA despite continuation of IBD therapy., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Immune-mediated comorbidities in patients with psoriasiform eczema are common. It can be challenging to manage multiple immune-mediated diseases, especially considering that biologic treatments are prone to causing paradoxical effects. The aim of this retrospective observational case series was to describe the course of both psoriasiform eczema and immune-mediated comorbidities in five patients treated with upadacitinib for psoriasiform dermatitis. Five patients, all male, were included. All the patients suffered from psoriasiform eczema. Moreover, two of the patients suffered from alopecia areata, two from vitiligo, one from ulcerative colitis and one from hidradenitis suppurativa. In all cases, the treatment with upadacitinib was rapidly effective on the eczema. The effectiveness on alopecia areata was good in both cases, while the results on vitiligo were only partial. The only case of ulcerative colitis achieved complete remission, while the case of hidradenitis suppurativa experience partial improvement. In conclusion, upadacitinib was effective in treating not only psoriasiform eczema, but also several immune mediated comorbidities. Additional studies are necessary to determine the efficacy of upadacitinib in alopecia areata, vitiligo and hidradenitis suppurativa., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Salvi, Parodi, Cozzani and Burlando.)

Alopecia areata is the second most common form of hair loss in humans after androgenetic alopecia. Although a variety of animal models for alopecia areata have been described, currently the C3H/HeJ mouse model is the most commonly used and accepted. Spontaneous hair loss occurs in 15%-25% of older mice in which the lesions wax and wane, similar to the human disease, with alopecia being more common and severe in female mice. Full-thickness skin grafts from mice with spontaneous alopecia areata to young, normal-haired, histocompatible mice provide a highly reproducible model with progressive lesions that makes it useful for drug efficacy and mechanism-based studies. As alopecia areata is a cell-mediated autoimmune disease, transfer of cultured lymph node cells from affected mice to unaffected, histocompatible recipients also promotes disease development and provides an alternative, nonsurgical protocol. Protocols are presented to produce these models such that they can be used to study alopecia areata and to develop novel drug therapies. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Full-thickness skin grafts to reproducibly induce alopecia areata in C3H/HeJ mice Basic Protocol 2: Adoptive transfer of cultured lymphoid cells provides a nonsurgical method to induce alopecia areata in C3H/HeJ mice., (© 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC.)

The TEC (tyrosine kinase expressed in hepatocellular carcinoma) family kinases, an important class of protein kinases, play key roles in cell signaling and immune regulation. In this review, the association between the pathogenesis of alopecia areata and the structure and regulatory mechanisms of TEC family kinases in normal physiological processes, is explored. Furthermore, the potential clinical applications of TEC kinases and their inhibitors are highlighted by summarizing current insights into their mechanisms of action, clinical applications, and recent advancements in TEC kinase inhibitor research., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The scalp microbiome represents an array of microorganisms important in maintaining scalp homeostasis and mediating inflammation. Scalp microbial dysregulation has been implicated in dermatologic conditions including alopecia areata (AA), dandruff/seborrheic dermatitis (D/SD), scalp psoriasis (SP) and folliculitis decalvans (FD). Understanding the impact of scalp microbial dysbiosis gives insight on disease pathophysiology and guides therapeutic decision making. Herein we review the scalp microbiome and its functional role in scalp conditions by analysis of metagenomic medical literature in alopecia, D/SD, SP, and other dermatologic disease.Increased abundance of Malassezia, Staphylococcus, and Brevibacterium was associated with SD compared to healthy controls. A higher proportion of Corynebacterium, actinobacteria, and firmicutes are present in AA patients, and lower proportions of Staphylococcus caprae are associated with worse clinical outcomes. Decreased prevalence of actinobacteria and Propionibacterium and increased firmicutes, staphylococcus, and streptococcus are associated with scalp psoriasis. Studies of central centrifugal cicatricial alopecia (CCCA) suggest scalp microbial composition contributes to CCCA's pro-inflammatory status. The most common organisms associated with FD include methicillin-resistant S. aureus and S. lugdunensis. Antifungals have been a mainstay treatment for these diseases, while other alternatives including coconut oils and shampoos with heat-killed probiotics have shown considerable potential efficacy by replenishing the scalp microbiome., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Alopecia areata (AA) is nonscarring hair loss characterized by Th1 and concomitant Th2 skewing, particularly in atopic patients. Despite novel developments for adult AA, safe and effective treatments for pediatric patients remain limited. Dupilumab, with a well-studied safety profile, may have therapeutic potential for atopic pediatric AA. To evaluate the ability of dupilumab to regrow hair in pediatric AA patients. We conducted a single-center, retrospective, observational study to evaluate hair regrowth [using Severity of Alopecia Tool (SALT)] with dupilumab in 20 children with both AD and AA (age range 5-16 years, mean 10.8 years; baseline SALT range 3-100, mean 54.4). Patient demographics, atopic history, IgE and SALT scores were collected at 12wk follow-up visits, up to > 72wks, to evaluate hair regrowth. Spearman correlations with clinical data were performed. Patients showed clinical improvement over the follow-up period (range 24 to > 72wks, mean 67.6wks) with significant mean(± SD) reduction in SALT at 48wks versus baseline [20.4(± 35.1) vs 54.4(± 37.6), respectively; p < 0.01] and continued improvement up to > 72wks [2.2(± 4.9), p < 0.01]. Baseline SALT positively correlated with disease duration (r = 0.54, p < 0.01), and negatively correlated with improvement in SALT at weeks 24, 36, and 48 (|r|≥ 0.65, p < 0.01 for all comparisons). Baseline IgE positively correlated with improvement in SALT at week 36 (r > 0.60, p < 0.05). Dupilumab was well-tolerated, with no new safety concerns. These real-world data support the utility of dupilumab to safely treat pediatric AA patients, corroborating the role of Th2 skewing in children with AA and associated atopy, warranting larger clinical trials., (© 2024. The Author(s).)

Severe alopecia areata (AA) is a nonscarring hair loss for immune disorder and SALT score ≥ 50%. The guidelines for managing patients with severe AA suggest treatments: systemic steroids, JAK inhibitors, and contact immunotherapy. However, there is a lack of evidence indicating the superiority of one treatment over another. Therefore, this study aimed to identify the most effective treatment for severe AA through network meta-analysis. Following the PRISMA guidelines, we conducted a network meta-analysis. The literature search was retrieved across four databases. The Cochrane 5.1 risk of bias assessment tool and ROBINS-I tool assessed quality of the included studies. Subsequently, efficacy and safety comparisons among the three treatments were conducted using Stata 14.0 on account of the frequency method. The SUCRA rank indicated that oral dexamethasone (95.9%) > diphenylcyclopropenone(DPCP) (74.5%) > oral ritlecitinib (62.6%) > oral baricitinib (46.9%) > squaric acid dibutyl ester(SADBE) (20.1%) > placebo (0.0%) from high to low in the aspect of improving efficacy. As for safety, placebo(88.4%) > oral ritlecitinib (86.5%) > oral baricitinib (62.1%) > SADBE (37.0%) > oral dexamethasone(22.3%) > DPCP(3.8%) in the aspect of decreasing adverse events. Oral dexamethasone and DPCP showed superior efficacy compared to oral ritlecitinib and oral baricitinib. However, in terms of safety, oral ritlecitinib was preferable. Some adverse events associated with oral dexamethasone and DPCP were intolerable to patients, whereas those related to oral ritlecitinib and oral baricitinib were more manageable. Overall, ritlecitinib and baricitinib remain promising drugs in the future treatment of severe AA., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Corona virus disease 2019(COVID-19) is one of the most serious respiratory pandemic diseases threatening human health for centuries. Alopecia areata (AA) is a sudden patchy hair loss, an autoimmune disease, which seriously affects the image and mental health of patients. Evidence shows that the risk of autoimmune diseases significantly increases after COVID-19, and is positively correlated with the severity, with a significant increase in the risk of alopecia in those over 40 years old. The relationship between COVID-19 and AA has become a hot topic of current research. Strengthening the research on the correlation between COVID-19 and AA can help to identify and protect susceptible populations at an early stage. This article reviews the research progress on the epidemiological background of COVID-19 and AA, the situation and possible mechanisms of AA induced by COVID-19 or COVID-19 vaccination, and potential treatment methods., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Xie, Lv, Luo, Chen, Du, Xu and Yang.)

Alopecia areata (AA) is an autoimmune inflammatory disease characterized by non-scarring hair loss due to an immune response that targets hair follicles. The current treatment approach for AA involves the use of immunosuppressants and immunomodulators to reduce cytokine levels around affected hair follicles. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as potential anti-inflammatory agents with diverse beneficial effects in various medical conditions. This study investigates the role of beta-hydroxybutyrate (BHB), a ketone body produced during SGLT2 inhibition, in the pathogenesis of AA. Serum BHB levels were found to be significantly elevated in patients with AA compared with healthy controls, with higher levels correlating with severity of hair loss. BHB treatment increased inflammatory cytokine production in outer root sheath (ORS) cells, mimicking the inflammatory conditions seen in AA. The results suggest that elevated BHB levels may exacerbate the inflammatory immune response in AA patients and may be associated with chronic hair loss and resistance to treatment. Serum BHB levels may serve as a potential marker of poor prognosis in patients with severe AA. Further research is needed to elucidate the precise role of BHB in the pathogenesis of AA and its implications for disease management., (© 2024 The Author(s). Experimental Dermatology published by John Wiley & Sons Ltd.)

Down syndrome is the most common genetic cause of intellectual disability and has previously been associated with a variety of autoimmune disorders affecting multiple organ systems. The high prevalence of autoimmune disease, in conjunction with other inflammatory and infectious diseases, in this population suggests an intrinsic immune dysregulation associated with triplication of chromosome 21. Emerging data on the role of chromosome 21 in interferon activation, cytokine production, and activation of B-cell mediated autoimmunity are emerging hypotheses that may explain the elevated prevalence of autoimmune thyroid disease, celiac disease, type I diabetes, autoimmune skin disease, and a variety of autoimmune neurologic conditions. As the life expectancy for individuals with Down syndrome increases, knowledge of the epidemiology, clinical features, management and underlying causes of these conditions will become increasingly important. Disorders such as Hashimoto's thyroiditis are prevalent in between 13 and 34% of individuals with Down syndrome but only 3% of the neurotypical population, a pattern similarly recognized in individuals with Celiac Disease (5.8% v 0.5-2%), alopecia areata (27.7% v. 2%), and vitiligo (4.4% v. 0.05-1.55%), respectively. Given the chronicity of autoimmune conditions, early identification and management can significantly impact the quality of life of individuals with Down syndrome. This comprehensive review will highlight common clinical autoimmune conditions observed in individuals with Down syndrome and explore our current understanding of the mechanisms of disease in this population., (© 2024. The Author(s).)

Chronic inflammatory skin diseases are multifactorial diseases that combine genetic predisposition, environmental triggers, and metabolic disturbances associated with abnormal immune responses. From an immunological perspective, the better understanding of their physiopathology has demonstrated a large complex network of immune cell subsets and related cytokines that interact with both epidermal and dermal cells. For example, in type-1-associated diseases such as alopecia areata, vitiligo, and localized scleroderma, recent evidence suggests the presence of a type-2 inflammation that is well known in atopic dermatitis. Whether this type-2 immune response has a protective or detrimental impact on the development and chronicity of these diseases remains to be fully elucidated, highlighting the need to better understand its involvement for the management of patients. This mini-review explores recent insights regarding the potential role of type-2-related immunity in alopecia areata, vitiligo, and localized scleroderma., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Migayron, Bordes, Closs, Seneschal and Boniface.)

Alopecia areata (AA) is an autoimmune disease that develops due to inflammation and causes sudden hair loss. Ithas been observed that family circumstances may contribute to the development of AA. This study aims to assessthe relationship between the development of alopecia areata in children, family functions, and depression andanxiety levels in their parents.Thirty-nine participants diagnosed with AA and 41 healthy controls (HC), agedbetween 8 and 18 years, and their parents participated in the study. The assessment of the children included thecompletion of a socio-demographic data form, the Parenting Style Scale (PSS), and the Revised Children's Anxietyand Depression Scale (RCADS). The parents provided information on a sociodemographic form, the BeckDepression Inventory (BDI), and the Beck Anxiety Inventory (BAI). The children in the control group scoredsignificantly higher on the PSS acceptance/ involvement subscale than those with AA. In the AA group, the numberof authoritative and indulgent (PSS) families was statistically significantly lower than that of the families in the HC,and the number of neglectful families was statistically significantly higher than those of the control group. Totalanxiety and depression t scores (RCADS) were statistically significantly higher in the AA children than in theHC. Our study demonstrates the importance of considering familial factors and parental mental health tounderstand and address alopecia areata in children. Our findings support the psychosomatic component of AA.Implementing comprehensive treatment strategies that target psychological well-being and family dynamics couldprove crucial., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Biologics and Janus kinase (JAK) inhibitors are immunomodulating and immunosuppressing medications utilized to treat atopic dermatitis (AD), psoriasis (PSO), psoriatic arthritis (PsA), and alopecia areata (AA). Special recommendations must be considered when prescribing vaccinations in this population, as the pneumococcal and herpes zoster vaccine are recommended to patients ≥ 19-years-old (rather than ≥ 65-years-old and ≥ 50-years-old as in the general population, respectively), along with a yearly influenza and up to date COVID-19 vaccination. Additionally, TNF-α and JAK-inhibitors may increase the risk of latent Hepatitis B virus (HBV) reactivation among high-risk patients. Prior to prescribing these medications, a quantitative HepB Surface Antibody (HepB SA) test is performed to determine immunity. This study utilized the SlicerDicer function on EPIC Medical Records to search for any patient ≥ 19-years-old prescribed a biologic or JAK inhibitor for AD, PSO, PsA, or AA between 10/2003 and 10/2023 at a large tertiary institution. Vaccination rates among patients on biologics and JAK inhibitors were low, with rates being significantly lower in patients 19-64 years-old, compared to those ≥ 65 years-old for most disease states (p < 0.01). Among AD, PSO/PsA, and AA patients, on average, 9.39% were vaccinated for influenza, 6.76% for herpes zoster, 16.56% for pneumococcal pneumonia, and 63.98% for COVID-19. Only 3.16% of patients were adequately vaccinated for HepB after an abnormal HepB SA test. Here, extremely low rates of vaccination among patients on biologics and JAK inhibitors at our institution were highlighted, emphasizing the imperative need for ensuring vaccination in this group., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Previous studies demonstrated that Th1 cytokines like IL-2, IL-12 and IFN-γ have initiatory role in alopecia areata (AA) and positive correlation with disease severity. They informed that serum levels of Th17 cytokines, IL-17, IL-22, IL-23 increased in active AA patients and corelated, particularly IL-17, with disease severity. In recent reports it was showed the balance between Th17 and Treg cells is crucial for maintaining tolerance to self-antigens, and an imbalance towards Th17 may contribute to the development of autoimmune diseases like AA. But research on serum Treg markers in AA is limited. It was aimed to investigate whether the Treg cells have a role in the pathogenesis of AA analyzing the serum levels of Treg cytokines IL-35 and TGF-β in the patients with AA. 42 AA patients and 38 healthy controls were enrolled. Patient demographics, clinical data, disease severity assessed by Severity of Alopecia Tool (SALT) scores were recorded. Serum samples were collected and analyzed for TGF-β and IL-35 levels using ELISA kits. The cytokine levels in both groups were statistically compared. Their relation with parameters of demographic and severity of disease was evaluated. The patient and control groups had no statistically significant difference, there was 71.4% males and 28.6% females in patient group, while the control group had 63.2% males and 36.8% females, Severity analysis classified 18 patients with mild AA, 19 with moderate AA, and 5 with alopecia totalis/areata universalis. While TGF-β levels exhibited no significant difference between groups, IL-35 levels were significantly elevated in AA patients (p = 0.002). Logistic regression identified IL-35 as a significant parameter influencing disease status (OR = 1.055). Correlation analysis revealed a weak positive correlation between patient age and IL-35 levels (r = 0.436; p = 0.004). Notably, IL-35 levels displayed a significant decrease in individuals with antinuclear antibody (ANA) positivity. No correlations were identified between cytokine levels and disease severity, prognosis, or disease activity. Elevated IL-35 levels suggest that IL-35 and specific Treg cell subsets can play a role in AA pathogenesis. The nuanced roles of TGF-β and IL-35 highlight the need for comprehensive studies to interpret their implications in the complex immunopathogenesis of AA. These findings open avenues for further research, positioning IL-35 as a prospective target for investigating and potentially intervening in AA pathogenesis., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Alopecia areata (AA) is an autoimmune-mediated disorder in which the proximal hair follicle (HF) attack results in non-scarring partial to total scalp or body hair loss. Despite the growing knowledge about AA, its exact cause still needs to be understood. However, immunity and genetic factors are affirmed to be critical in AA development. While the genome-wide association studies proved the innate and acquired immunity involvement, AA mouse models implicated the IFN-γ- and cytotoxic CD8+ T-cell-mediated immune response as the main drivers of disease pathogenesis. The AA hair loss is caused by T-cell-mediated inflammation in the HF area, disturbing its function and disrupting the hair growth cycle without destroying the follicle. Thus, the loss of HF immune privilege, autoimmune HF destruction mediated by cytotoxic mechanisms, and the upregulation of inflammatory pathways play a crucial role. AA is associated with concurrent systemic and autoimmune disorders such as atopic dermatitis, vitiligo, psoriasis, and thyroiditis. Likewise, the patient's quality of life (QoL) is significantly impaired by morphologic disfigurement caused by the illness. The patients experience a negative impact on psychological well-being and self-esteem and may be more likely to suffer from psychiatric comorbidities. This manuscript aims to present the latest knowledge on the pathogenesis of AA, which involves genetic, epigenetic, immunological, and environmental factors, with a particular emphasis on immunopathogenesis.

Alopecia areata refers to an autoimmune illness indicated by persistent inflammation. The key requirement for alopecia areata occurrence is the disruption of immune-privileged regions within the hair follicles. Recent research has indicated that neuropeptides play a role in the damage to hair follicles by triggering neurogenic inflammation, stimulating mast cells ambient the follicles, and promoting apoptotic processes in keratinocytes. However, the exact pathogenesis of alopecia areata requires further investigation. Recently, there has been an increasing focus on understanding the mechanisms of immune diseases resulting from the interplay between the nervous and the immune system. Neurogenic inflammation due to neuroimmune disorders of the skin system may disrupt the inflammatory microenvironment of the hair follicle, which plays a crucial part in the progression of alopecia areata., (© 2024 Japanese Dermatological Association.)

The autoimmunity-promoting cytokine, Interleukin-15 (IL-15), is often claimed to be a key pathogenic cytokine in alopecia areata (AA). Yet, rhIL-15 promotes human hair follicle (HF) growth ex vivo. We have asked whether the expression of IL-15 and its receptor (IL-15R) isoforms is altered in human AA and how IL-15 impacts on human HF immune privilege (HF-IP) in the presence/absence of interferon-γ (IFNγ), the well-documented key AA-pathogenic cytokine, as well as on hair regrowth after experimental AA induction in vivo. Quantitative immunohistomorphometry showed the number of perifollicular IL-15 + T cells in AA skin biopsies to be significantly increased compared to healthy control skin, while IL-15, IL-15Rα, and IL-15Rγ protein expression within the hair bulb were significantly down-regulated in AA HFs. In organ-cultured human scalp HFs, rhIL-15 significantly reduced hair bulb expression of MICA, the key "danger" signal in AA pathogenesis, and increased production of the HF-IP guardian, α-MSH. Crucially, ex vivo, rhIL-15 prevented IFNγ-induced HF-IP collapse, restored a collapsed HF-IP by IL-15Rα-dependent signaling (as documented by IL-15Rα-silencing), and protected AA-preventive immunoinhibitory iNKT10 cells from IFNγ-induced apoptosis. rhIL-15 even promoted hair regrowth after experimental AA induction in human scalp skin xenotransplants on SCID/beige mice in vivo. Our data introduce IL-15 as a novel, functionally important HF-IP guardian whose signaling is constitutively defective in scalp HFs of AA patients. Our data suggest that selective stimulation of intrafollicular IL-15Rα signaling could become a novel therapeutic approach in AA management, while blocking it pharmacologically may hinder both HF-IP restoration and hair re-growth and may thus make HFs more vulnerable to AA relapse., Competing Interests: Declaration of Competing Interest None declared. For the record, RP and JG are employees of, and JC and AG consult for a company that develops hair growth-modulatory agents (www.cutaneon.com)., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment loss, respectively. In AA, inflammatory cell infiltrates are in the deep reticular dermis close to the hair bulb (swarm of bees), whereas in vitiligo the inflammatory infiltrates are in the epidermis and papillary dermis. Immune privilege collapse has been extensively investigated in AA pathogenesis, including the suppression of immunomodulatory factors (e.g., transforming growth factor-β (TGF-β), programmed death-ligand 1 (PDL1), interleukin-10 (IL-10), α-melanocyte-stimulating hormone (α-MSH), and macrophage migration inhibitory factor (MIF)) and enhanced expression of the major histocompatibility complex (MHC) throughout hair follicles. However, immune privilege collapse in vitiligo remains less explored. Both AA and vitiligo are autoimmune diseases that share commonalities in pathogenesis, including the involvement of plasmacytoid dendritic cells (and interferon-α (IFN- α) signaling pathways) and cytotoxic CD8+ T lymphocytes (and activated IFN-γ signaling pathways). Blood chemokine C-X-C motif ligand 9 (CXCL9) and CXCL10 are elevated in both diseases. Common factors that contribute to AA and vitiligo include oxidative stress, autophagy, type 2 cytokines, and the Wnt/β-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

Introduction: Alopecia areata (AA) is an autoimmune disease induced by viral infection or vaccination. With the increased incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the incidence of AA has also increased. Recently the incidence was found to be 7.8% from a previously reported rate of 2.1%. The physical and psychological damage caused by AA could seriously affect patients' lives, while AA is a challenging dermatological disease owing to its complex pathogenesis., Areas Covered: This paper presents a comprehensive review of the prevalence, pathogenesis and potential therapeutic targets for AA after infection with SARS-CoV-2 or SARS-CoV-2 vaccine., Expert Opinion: The treatment of AA remains challenging because of the complexity of its pathogenesis. For patients with AA after SARS-CoV-2 infection or vaccination, the use of sex hormones and alternative regenerative therapies may be actively considered in addition to conventional treatments. For preexisting disease, therapeutic agents should be adjusted to the patient's specific condition.

Alopecia areata is a representative inflammatory skin disease that is associated with various environmental stimuli. While psychological stress is believed to be a major pathogenetic trigger in alopecia areata, infants and newborns also suffer from the disease, suggesting the possible presence of other environmental factors. Daily lifestyle is well known to be involved in various inflammatory diseases and influences the severity of inflammatory skin diseases. However, only a limited number of studies have summarized these influences on alopecia areata. In this review article, we summarize lifestyle factor-related influences on the pathogenesis of alopecia areata and focus on environmental factors, such as smoking, alcohol consumption, sleep, obesity, fatty acids, and gluten consumption.

Alopecia areata is a type of non-scarring hair loss. The dysregulation of numerous systemic Th1 (IL-2, IFN-γ, TNF, IL-12, and IL-18), Th2 (IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17E, IL-31 and IL-33) and Th17 (IL-17, IL-17F, IL-21, IL-22, IL-23 and TGF-β) cytokines was observed in patients with alopecia areata. Positive correlations between the severity of alopecia areata and an increased serum level of various cytokines including IL-2, TNF, IL-12, IL-17, and IL-17E were reported in the literature. An increased serum level of numerous cytokines, such as IL-2, IL-6, TNF, IL-12, IL-17E, and IL-22, was described as positively correlated with the duration of the disease. Moreover, it was shown that increased pre-treatment serum level of IL-12 was a positive, while increased serum levels of IL-4 and IL-13 were negative prognostic markers for the efficacy of diphenylcyclopropenone. In conclusion, alopecia areata is associated with the dysregulation of systemic Th1, Th2 and Th17 cytokines with their role in the pathogenesis, clinical manifestations and prognosis of the disease. Available data indicate the most significant role of serum IL-2, TNF, IL-12, IL-17, and IL-17E as markers of disease activity. The serum levels IL-4, IL-12 and IL-13 may be useful as potential predictors of diphenylcyclopropenone efficacy.

Abstract: The definition of IgG4-related diseases incorporates a broad range of systemic diseases particularly a subset dominated by fibroinflammation. CD4+cytotoxic T cells have emerged as the major driving force for the fibroinflammation, and the pathogenetic role of IgG4 still remains to be determined. Cutaneous involvement is uncommon and is not well defined as elevated tissue IgG4 plasma cells are not a specific marker and prominent cutaneous fibroinflammation is often absent in cutaneous disease. We report the case of a patient with longstanding alopecia universalis and severe atopic dermatitis who presented with diffuse induration and mottled dyspigmentation of his scalp. Multiple scalp biopsies revealed diffuse interfollicular fibroinflammation and IgG4 plasma cells with induction of distinctive dedifferentiated follicles not seen in alopecia areata. This complex case may provide insight into the role of specific subsets of T cells not only in respect to the fibroinflammation linked to IgG4-related diseases but also the capacity to modify disease, follicular stem cell activation, immune privilege, cytotoxicity in alopecia areata, and the presence of atopy that may have contributed to the pathogenesis of this case., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)

Murine γδT-cells have stress-surveillance functions and are implicated in autoimmunity. Yet, whether human γδT-cells are also stress sentinels and directly promote autoimmune responses in the skin is unknown. Using a novel (mini-)organ assay, we tested if human dermis resident γδT-cells can recognize stressed human scalp hair follicles (HFs) to promote an alopecia areata (AA)-like autoimmune response. Accordingly, we show that γδT-cells from healthy human scalp skin are activated (CD69 + ), up-regulate the expression of NKG2D and IFN-γ, and become cytotoxic when co-cultured with autologous stressed HFs ex vivo. These autologous γδT-cells induce HF immune privilege collapse, dystrophy, and premature catagen, i.e. three hallmarks of the human autoimmune HF disorder, AA. This is mediated by CXCL12, MICA, and in part by IFN-γ and CD1d. In conclusion, human dermal γδT-cells exert physiological stress-sentinel functions in human skin, where their excessive activity can promote autoimmunity towards stressed HFs that overexpress CD1d, CXCL12, and/or MICA., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: C3H/HeJ mouse models progress gradually in hair loss from acute to chronic phase and reflect the symptoms of patients with alopecia areata (AA). However, the underlying pathological characteristics alteration associated with disease progression and autoantigens remain unclear., Objective: We aimed at elucidating the pathological differences between acute and chronic-AA in the C3H/HeJ mouse model., Methods: We analyzed populations of PBMCs, skin-draining lymph node (SDLN) cells, and cutaneous cells of AA mice using flow cytometry. The cytokine and chemokine expressions in the serum and skin were determined using multiplex assay and qPCR. The antibody serum levels were determined using ELISA and the antigen-specific T cells were detected using the MHC class I tetramer., Results: The CD8 + NKG2D + T and CD8 + T EM cell percentage in the chronic-AA SDLNs or among the unaffected and acute-AA mice PBMCs increased. The Th1 and CD4 + T EM cell percentage in the SDLNs and among PBMCs increased in the unaffected and AA mice. The percentage of CD8 + T EM /T RM cells and MHC class I expression increased in the lesions of acute-AA or the non-lesions and lesions of chronic-AA. The Th1 cells, dendritic cell-related cytokines, CD11c + cells and MHC class II expression increased in the skin of AA mice. The antibody levels and TYRP2 and tyrosinase-specific CD8 + T cell percentages were upregulated in AA mice., Conclusion: These results suggest that the CD8 + and CD4 + T cell subpopulations, cytokine and chemokine expressions differ between the disease phases. Moreover, TYRP2 and tyrosinase are potential autoreactive targets in the AA mouse model., Competing Interests: Declaration of Competing Interest All authors are employees of Maruho Co., Ltd., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Alopecia areata (AA) has long been associated with thyroid diseases; however, the temporality of their association remains unclear. This study aimed to investigate the bidirectional association between AA and thyroid diseases. In analysis 1, we included 5929 AA patients and 59,290 matched controls to assess the risk of thyroid diseases. In analysis 2, we included 35,071 patients with thyrotoxicosis, 19,227 patients with Graves' disease, 5460 patients with thyroiditis, 3352 patients with Hashimoto's thyroiditis, and their matched controls (1:10) to assess the risk of AA. Incidence of thyroid diseases and AA were the outcomes in analysis 1 and analysis 2, respectively. After adjusting the potential confounders, AA patients had an increased risk of all thyroid diseases, including toxic nodular goiter, (aHR 10.17; 95% confidence interval [CI] 5.32-19.44), nontoxic nodular goiter (aHR 5.23; 95% CI 3.76-7.28), thyrotoxicosis (aHR 7.96; 95% CI 6.01-10.54), Graves' disease (aHR 8.36; 95% CI 5.66-12.35), thyroiditis (aHR 4.04; 95% CI 2.12-7.73), and Hashimoto thyroiditis (aHR 4.35; 95% CI 1.88-10.04). On the contrary, a significantly increased risk of developing AA was observed among patients with thyrotoxicosis (aHR 9.29; 95% CI, 7.11-12.14), Graves' disease (aHR 8.66; 95% CI 6.03-12.42), and thyroiditis (aHR 6.42; 95% CI 3.15-13.11) but not in patients with Hashimoto's thyroiditis. In conclusion, our study found a bidirectional association between AA and thyroid diseases, suggesting shared biological mechanisms underlying these two diseases.

Background: Alopecia areata (AA) is an autoimmune disease resulting in non-scarring hair loss. Animal models are useful means to identify candidates for therapeutic agents. The C3H/HeJ mouse AA model induced via transferring cultured lymphoid cells isolated from AA-affected mice is widely used for AA research. However, this conventional method requires the continuous breeding of AA mice., Objective: We aimed to establish a new method to generate AA model using the transfer of cryopreserved cells, which allows the rapid induction of a large number of AA mice when needed., Methods: We cryopreserved lymph node cells soon after isolation from AA-affected mice and injected thawed-cultured cells into recipient mice. H&E staining, immunohistochemical staining, quantitative real-time PCR and ELISA were conducted to identify pathological characteristics. Flow cytometry was performed to reveal the profile of transferred cells., Results: More than 90 % of recipient mice developed AA-like hair loss and showed inflammatory cell infiltration around anagen hair follicles, markedly increased mRNA expressions of interferon-γ, CXCL11, and granzyme B, and elevated interferon-α protein levels in the skin compared with naïve mice. Higher percentages of effector memory T cells and dendritic cells in transferred cells resulted in a higher incidence of AA., Conclusion: This is the first report to establish a method for generating AA mice using cryopreserved lymphocytes. These AA mice have similar pathological characteristics to AA mice generated with the conventional method and AA patients. This convenient and reproducible method is expected to be valuable for AA study., Competing Interests: Declaration of Competing Interest All authors are employees of Maruho Co., Ltd., (Copyright © 2021 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Patients suffering from alopecia areata (AA) can lose hair in focal regions, the complete scalp, including eyelashes and eyebrows, or even the entire body. The exact pathology is not yet known, but the most described theory is a collapse of the immune privilege system, which can be found in some specific regions of the body. Different treatment options, local and systemic, are available, but none of them have been proven to be effective in the long term as well for every treatment there should be considered for the possible side effects. In many cases, treated or non-treated, relapse often occurs. The prognosis is uncertain and is negatively influenced by the subtypes alopecia totalis and alopecia universalis and characteristics such as associated nail lesions, hair loss for more than 10 years and a positive familial history. The unpredictable course of the disease also makes it a mental struggle and AA patients are more often associated with depression and anxiety compared to the healthy population. Research into immunology and genetics, more particularly in the field of dendritic cells (DC), is recommended for AA as there is evidence of the possible role of DC in the treatment of other autoimmune diseases such as multiple Sclerosis and cancer. Promising therapies for the future treatment of AA are JAK-STAT inhibitors and PRP.

Background: The gut microbiota is known to play a key role in autoimmune diseases., Objectives: To identify and compare the characteristics in the gut microbial composition of patients with alopecia areata (AA) and healthy controls (HCs)., Methods: In a cross-sectional discovery cohort, we enrolled 33 patients with AA and 35 HCs from the same geographic location in Shanghai, China. The 16S rRNA gene sequencing and bioinformatic analyses were conducted to analyze DNA extracted from the subjects., Results: The α-diversity of the AA group demonstrated no statistically significant differences compared with the HC group (P > 0.05). However, the overall gut microbial communities in the AA group were distinct from the HCs (P = 0.0096). We also adopted a random forest model to select three AA-associated OTU biomarkers: OTU1237(Achromobacter), OTU257(Megasphaera), and OTU1784(Lachnospiraceae Incertae Sedis)., Conclusion: The overall gut microbial composition for AA was distinct from that of HCs. The gut microbial markers we identified may potentially be used for earlier diagnosis and as therapeutic targets., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2021 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Background: Platelet-rich plasma has shown some promise in the treatment of alopecia areata., Objective: To evaluate the effect of platelet-rich plasma on hair regrowth and lesional T-cell cytokine expression in alopecia areata., Methods: This was a randomized, placebo-controlled, split-head study involving 27 patients with alopecia areata (Severity of Alopecia Tool score ≥25%). Alopecia patches on either side of the scalp were randomized to receive 3 intradermal injections of platelet-rich plasma or normal saline at monthly intervals and evaluated 3 months after the last session. Lesional T-cell cytokine messenger RNA expression was compared pre- and posttreatment in the platelet-rich plasma-treated sites., Results: The mean Severity of Alopecia Tool score did not change significantly compared with baseline with either platelet-rich plasma or placebo injections at any visit; however, the mean percentage reduction in the score in the platelet-rich plasma arm was more than in the placebo arm (9.05% ± 36.48% vs 4.99% ± 33.88%; P = .049) at final assessment. The mean interferon gamma (P = .001) and interleukin 17 cytokine (P = .009) messenger RNA expression decreased, whereas the mean interleukin 10 (P = .049) and FOXP3 (P = .011) messenger RNA expression increased significantly after platelet-rich plasma treatment., Limitations: Small sample size and a relatively short follow-up., Conclusion: Platelet-rich plasma was found to have limited efficacy in alopecia areata. However, it may play a role in restoring immune balance in the alopecic patches., (Copyright © 2020 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Alopecia areata (AA) is a multi-factors disease characterized by non-scarring hair loss. AA could be classified into three main clinical phenotypes including patchy type AA (AAP), alopecia totalis (AT) and alopecia universalis (AU) based on the severity and areas of hair loss. Recent studies suggested immunological factor was critical in AA, but the precise aetiology and pathogenesis of AA still need exploration. In the work, we screened two gene expression profiles (GSE45512 and GSE68801) from Gene Expression Omnibus (GEO). Based on the two data sets, 10 upregulated genes and 107 downregulated genes in AA skin biopsies were identified. CCL13, as one of the remarkably upregulated genes, was found to have potential biological functions in aberrant immune response of AA according to the GO and KEGG analyses. The PPI network showed CCL13 was associated with multiple immune-related genes. The expression of CCL13 was increased depending on the severity of disease in AA patients. Cytotoxic lymphocytes, T cells and myeloid dendritic cells accumulated remarkably in scalp tissue depending on the severity of AA, and CCL13 was significantly correlated to cytotoxic lymphocytes, T cells and myeloid dendritic cells in AA patients. Our RT-PCR and ELISA results found CCL13 was upregulated in skin biopsy and serum of AA patients, and the immunohistochemistry (IHC) detection showed CCL13 was expressed by both the hair follicle epithelium and infiltrating immune cells. In conclusion, the upregulated of CCL13 and subsequent immune cell infiltration was related to AA, which could be a promising target for diagnosis and therapy in AA patients., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Alopecia areata (AA) is regarded as a tissue-specific and cell-mediated autoimmune disorder. Regarding the cytokine balance, AA has been considered a type 1 inflammatory disease. On the other hand, AA often complicates atopic dermatitis (AD) and AD is regarded as type 2 inflammatory disease. However, the immunological aspects of AA in relation to AD are still poorly understood. Therefore, we aim to clarify the immunological properties of AD-associated AA. In this study, we performed comparative analysis of the expression of intracytoplasmic cytokines (IFN-γ, IL-4, and IL-13), chemokine receptors (CXCR3 and CCR4) in peripheral blood which were taken from healthy controls, non-atopic AA patients, AA patients with extrinsic AD, and AA patients with intrinsic AD by flowcytometric analysis. We also compared the scalp skin samples taken from AA patients with extrinsic AD before and after treatment with dupilumab. In non-atopic AA patients, the ratios of CD4+IFN-γ+ cells to CD4 + IL-4 + cells and CD4 + IFN-γ + cells to CD4 + IL-13 + cells were higher than those in AA patients with extrinsic AD. Meanwhile, the ratio of CD8 + IFN-γ + cells to CD8+IL-13+ cells was significantly higher in the non-atopic AA than in the healthy controls. In AA patients with extrinsic AD, the skin AA lesion showed dense infiltration of not only CXCR3+ cells but also CCR4 + cells around hair bulb before dupilumab treatment. However, after the treatment, the number of CXCR3 + cells had no remarkable change while the number of CCR4 + cells significantly decreased. These results indicate that the immunological condition of AA may be different between atopic and non-atopic patients and between extrinsic and intrinsic AD patients. Our study provides an important notion that type 2 immunity may participate in the development of AA in extrinsic AD patients. It may be considered that the immunological state of non-atopic AA is different from that of atopic AA.