The Contributory Roles of Th17 Lymphocyte and Cytotoxic T Lymphocyte at the Hair Bulge Region as Well as the Hair Bulb Area in the Chronic Alopecia Areata Patients

Hematological ratios as an indicator of severity in alopecia areata: A retrospective nationwide study

BACKGROUND

Alopecia Areata (AA) is an autoimmune condition where the activation of Th1, Th2, and Th17 responses is known to stimulate other white blood cells, potentially affecting hematopoietic lineages. However, previous studies on AA have found no utility in hematological ratios. Our goals were to compare neutrophils-to-lymphocytes ratio (NLR), platelets-to-lymphocytes ratio (PLR), eosinophils-to-lymphocytes ratio (ELR), eosinophils-to-neutrophils ratio (ENR), and eosinophils-to-monocytes ratio (EMR) between patients with AA and controls, as well as between mild and moderate-severe AA cases.

METHODS AND FINDINGS

We performed a retrospective, population-based cohort study involving adult patients enrolled in the largest national health maintenance organization in Israel. The study comprised 147,020 AA patients and 141,598 healthy controls. AA patients exhibited a higher likelihood of elevated NLR and ELR compared to controls. Upon further classification based on severity, moderate-severe AA patients displayed higher values of NLR, PLR, ELR, and EMR compared to mild AA individuals OR = 1.11 [1.09-1.1], P<0.001; OR = 1.09 [1.05-1.13], P<0.001; OR = 2.06 [1.67-2.53], P<0.001; OR = 1.07 [1.03-1.07)], P<0.001, respectively). Similar trends were observed 12 to 18 months before diagnosis.

CONCLUSION

Our results not only deviate from the current literature but also offer a cost-effective, accessible, and efficient tool for enhanced disease prediction and management.

The value of immunohistochemical expression of SOX9 and CD34 in alopecia areata

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.

Deciphering the Complex Immunopathogenesis of Alopecia Areata

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.

Expression of Long Noncoding RNA, HOTAIR, and MicroRNA-205 and Their Relation to Transforming Growth Factor β1 in Patients with Alopecia Areata

Introduction

Alopecia areata (AA) is a common autoimmune condition that affects anagen hair follicles. The most commonly recognized theory is that it is a T-cell-mediated autoimmune disorder in a genetically susceptible individual. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) were thought to play a function in the pathogenesis. The expression of lncRNA HOTAIR and miRNA-205 and their relation to transforming growth factor β1 (TGF-β1) in AA were not studied.

Aim

The aim of the studywas to evaluate the role of miRNA-205, lncRNA, HOTAIR, and TGF-β1 levels in AA pathogenesis, clinical course, and severity of AA.

Methods

Two groups of subjects were included in this case-control study: 50 patients with AA and 50 healthy matched controls. miRNA-205 and lncRNA HOTAIR expression levels were assayed using quantitative RT-PCR, while serum levels of TGF-β1 were assayed using ELISA techniques.

Results

The serum expression of lncRNA HOTAIR was significantly downregulated in AA patients with a p value < 0.001, while the serum expression of both miRNA-205 and TGF-β1 were significantly upregulated in patients.

Discussion/Conclusion

This study highlights the potential role of high serum expression of miRNA-205 and TGF-β1 and the low serum expression of lncRNA HOTAIR in AA pathogenesis. This could be used as a therapeutic target to treat AA.

IL-33 Contributes to the Pathological Changes of Hair Follicles in Psoriasis: A Potential Target for Psoriatic Alopecia

Purpose

IL-33 is constitutively expressed in skin tissues. Alopecia, a T cells-driven disorder of the hair follicles (HFs), is a common complication in the development of psoriasis. However, the role of IL-33 in psoriatic alopecia remains uncovered. Here, we investigated the roles of IL-33 in inducing pathological changes of hair follicles in psoriasis.

Patients and Methods

Clinical samples and imiquimod (IMQ)-induced psoriatic mice samples were used to investigate the pathological changes and T-cell infiltration of HFs. By using immunohistochemistry staining, the distribution and expression alteration of IL-33 in HFs were determined. Next, by using IL-33 and ST2 knockout mice, we investigated the role of IL-33/ST2 axis in the pathological changes of HFs in psoriasis. Meanwhile, recombinant IL-33 protein was subcutaneous injected to confirm its effect. Finally, RNA sequencing was used to clarify the genes and signaling pathways that involved in this process. Differentially expressed genes were further verified by RT-PCR in cultured HFs in vitro.

Results

We found that the pathological changes of HFs and T cells infiltration in imiquimod-induced psoriatic mice were similar to that in psoriasis patients. The IL-33 positive keratinocytes in the outer root sheath of HFs were increased in both psoriasis patients and psoriatic model mice compared with the controls. By using gene knockout mice, we found that the pathological changes and T cell infiltration were attenuated in IL-33^-/- and ST2^-/- psoriatic model mice. In addition, subcutaneous injection of recombinant IL-33 exacerbated the pathological changes of HFs and T cell infiltration. RNA sequencing and RT-RCR revealed that IL-33 upregulated the transcription of genes related to keratinocytes proliferation and T lymphocytes chemotaxis.

Conclusion

Our study identifies that IL-33 promotes the pathological changes of HFs in psoriasis, which contributes to psoriatic alopecia. Inhibition of IL-33 may be a potential therapeutic approach for psoriatic alopecia.

IL-17 Expression in the Perifollicular Fibrosis in Biopsies From Lichen Planopilaris

BACKGROUND

Lichen planopilaris (LPP) is a primary lymphocytic cicatricial alopecia for which therapy is often ineffective and there is no cure.

OBJECTIVES

Looking for a new targetable molecule in the treatment of LPP, we sought to verify whether IL-17 expression is increased in scalp biopsies from patients with active scalp lesions of LPP.

METHODS

Horizontal sections of hematoxylin and eosin-stained slides from 40 scalp biopsies of active LPP were retrospectively collected and stained with the monoclonal antibody against IL-17 (Abcam, Cambridge, MA; ab79056, dilution 1:100). Twenty biopsies from patients with chronic telogen effluvium served as controls because of their morphological resemblance to the normal scalp. Statistical analysis was performed using IBM SPSS Statistics for Windows (IBM Corporation, Armonk, NY).

RESULTS

The main finding was the positive cytoplasmic expression of IL-17 in the perifollicular fibrosis of the affected follicles in LPP which was statistically significant compared with the controls ( P < 0.0001). The labeled cells were identified as fibroblasts based on their spindle shape and fascicular concentric arrangement in tight perifollicular distribution. Although most of the LPP specimens (n = 35; 87.5%) also revealed cytoplasmic IL-17 expression in the lichenoid inflammatory infiltrate, the results were not statistically significant ( P = 0.1351).

CONCLUSION

Our immunohistochemistry results show that blocking the IL-17 inflammatory pathway may interfere with the progression of the perifollicular fibrosis and inflammation in LPP.

Immune-mediated alopecias and their mechanobiological aspects

Alopecia is a non-specific term for hair loss clinically diagnosed by the hair loss pattern and histological analysis of patient scalp biopsies. The immune-mediated alopecia subtypes, including alopecia areata, lichen planopilaris, frontal fibrosing alopecia, and central centrifugal cicatricial alopecia, are common, significant forms of alopecia subtypes. For example, alopecia areata is the most common autoimmune disease with a lifetime incidence of approximately 2% of the world's population. In this perspective, we discuss major results from studies of immune-mediated alopecia subtypes. These studies suggest the key event in disease onset as the collapse in immune privilege, which alters the hair follicle microenvironment, e.g., upregulation of major histocompatibility complex molecules and increase of cytokine production, and results in immune cell infiltration, inflammatory responses, and damage of hair follicles. We note that previous studies have established that the hair follicle has a complex mechanical microenvironment, which may regulate the function of not only tissue cells but also immune cell infiltrates. This suggests a potential for mechanobiology to contribute to alopecia research by adding new methods, new approaches, and new ways of thinking, which is missing in the existing literature. To fill this a gap in the alopecia research space, we develop a mechanobiological hypothesis that alterations in the hair follicle microenvironment, specifically in the mechanically responsive tissues and cells, partially due to loss of immune privilege, may be contributors to disease pathology. We further focus our discussion on the potential for applying mechanoimmunology to the study of T cell infiltrates in the hair follicle, as they are considered primary contributors to alopecia pathology. To establish the connection between the mechanoimmunological hypothesis and immune-mediated alopecia subtypes, we discuss what is known about the role of T cells in immune-mediated alopecia subtypes, using the most extensively studied AA as our model.

The current state of knowledge of the immune ecosystem in alopecia areata

Alopecia areata (AA) is an autoimmune disease that affects approximately 2% of the general population. Patients with AA most commonly present with one or more patches of hair loss on the scalp in defined circular areas. A fraction of patients progress to more severe forms of the disease, in some cases with involvement of all body surfaces. The healthy anagen stage hair follicle is considered an immune privileged site, described as an environment that suppresses inflammatory immune responses. However, in AA, this immune privileged state collapses and marks the hair follicle as a target for the immune system, resulting in peri- and intrafollicular infiltration by lymphocytes. The complexity of the inflammatory ecosystem of the immune response to the hair follicle, and the relationships between the cellular and soluble participants, in AA remains incompletely understood. Many studies have demonstrated the presence of various immune cells around diseased hair follicles; however, often little is known about their respective contributions to AA pathogenesis. Furthering our understanding of the mechanisms of disease in AA is essential for the novel identification of targeted therapeutics that are efficacious and have few unintended effects.

Dietary Habits in Japanese Patients with Alopecia Areata

Purpose

Alopecia areata (AA) is characterized by non-scarring, patchy hair loss caused by autoimmune reactions to anagen hair follicles. The pathogenesis of AA may be affected by the diet. However, the dietary habits of patients with AA have not been precisely examined. Therefore, the aim of this study was to investigate the dietary habits of patients with AA in comparison to those of healthy controls.

Patients and Methods

We evaluated the dietary habits of 70 adult Japanese patients with AA using a brief-type self-administered diet history questionnaire and compared them to the habits of age- and sex-matched healthy controls.

Results

Japanese patients with AA had a higher body mass index (BMI) and higher intakes of vitamin C and fruit than the controls. Logistic regression analysis showed that AA was associated with BMI. Retinol intake was positively correlated with severity of alopecia tool (SALT) score, and linear regression analysis revealed that retinol intake was a predictor of SALT score. Retinol intake among patients with moderate to severe AA (ie, a SALT score >25) was higher than that in patients with mild AA (a SALT score ≤25). The mean age of AA patients with atopic dermatitis (AD) was lower than that of AA patients without AD; however, there were no differences in nutrient or food intake between these two groups. Logistic regression analysis showed that the comorbidity AD was negatively associated with age.

Conclusion

AA was associated with a high BMI, and high retinol intake was a predictor of SALT score. Further studies should be conducted to clarify whether dietary intervention to reduce BMI or limit retinol intake can alter the development or severity of AA.

Immunology of alopecia areata

Alopecia areata is a condition that affects hair follicles and leads to hair loss ranging from small well-defined patches to complete loss of all body hair. Despite its high incidence, the pathobiology is not fully understood, and no single concept could be universally accepted.

Alopecia areata is mostly considered to be an autoimmune disease, in which the collapse of hair follicle immune privilege plays a key role. Higher incidence rate in the female population and increased overall risk of other autoimmune disorders militate in favor of autoimmune hypothesis. Antibodies against multiple components of hair follicles almost exclusively attack in anagen phase, where melanogenesis takes place. It suggests involvement of melanogenesis-associated autoantigens as a target epitope.

Some investigators believed that alopecia areata is not a truly autoimmune disease but is only ‘consistent with’ autoimmune mechanisms. High frequency of a positive family history up to 42% may reflects the contribution of heredity factors. In addition, no specific target autoantigen has been identified so far, and autoantibodies to hair follicle-associated antigens are detectable in normal individuals.

Interferon-gamma serum level and immunohistochemical expression of CD8 cells in tissue biopsies in patients with alopecia areata in correlation with trichoscopic findings

Alopecia areata (AA) is an autoimmune form of nonscarring hair loss. The aim of the study was to assess the serum concentration of interferon gamma (IFN-γ) and CD8 cell expression in lesional skin biopsies in correlation with the disease severity, activity, duration, and trichoscopic findings in patients with AA. The study included 30 patients with AA and 15 age- and sex-matched healthy controls. Trichoscopy was performed and photographs were captured for the alopecic areas, and the enzyme-linked immunosorbent assay technique was used for serum level of IFN-γ assessment and immunohistochemistry for CD8 cells. The results obtained indicate that IFN-γ serum level in patients was significantly higher than that of control subjects, and significantly correlated with the activity status and the duration of the disease. CD8+ T cells infiltrate intensity significantly correlated with severity. Yellow dots (YDs), vellus hair, black dot, and exclamation marks were the most common trichoscopic findings. The presence of black dots significantly correlated to the disease activity, duration, serum IFN-γ, and CD8+ infiltrate intensity. The presence of YDs significantly correlated with the mean serum IFN-γ level. Exclamation marks significantly correlated with the disease activity and the degree of CD8+ infiltrate. In conclusion, trichoscopy could be a reliable indicator of the IFN-γ serum level and CD8+ T cell infiltrate intensity in AA patient.

Vitamin D and alopecia areata: possible roles in pathogenesis and potential implications for therapy

Alopecia areata is characterized by the loss of hair on the scalp and elsewhere on the body. It affects approximately 2% of the general population. It is believed to be an autoimmune disease. However, its pathogenesis remains incompletely understood. Recent studies have revealed a substantial link between vitamin D and alopecia areata. But the underlying mechanism still yet to be deciphered. This article reviews the current literature and discusses the possible roles of vitamin D in the pathogenesis of alopecia areata in the context of (1) loss of immune privilege in hair follicle, (2) autoreactive effector T cells and mast cells, (3) nature killer group 2 member d-positive cytotoxic T cells, (4) Janus kinase/signal transducers and activators of transcriptional signaling pathway, (5) regulatory T cells, (6) immune checkpoints, and (7) oxidative stress, which are believed to play important roles in autoimmunity in AA. This paper provides new insights into research directions to elucidate the exact mechanisms of vitamin D in the pathogenesis. Calcipotriol, a vitamin D analog, has been reported to be topically used in treating alopecia areata with promising results. Combination therapy of vitamin D analogs with corticosteroids might also be used in treating alopecia areata.

Alopecia areata patients show deficiency of FOXP3+CD39+ T regulatory cells and clonotypic restriction of Treg TCRβ-chain, which highlights the immunopathological aspect of the disease

Alopecia areata (AA) is a hair loss disorder resulting from an autoimmune reaction against hair follicles. T-helper 1 cells are a major contributor to this disorder, but little is known about the role of T-regulatory cells (Tregs) in AA. Here, we analysed the distribution of circulating Treg subsets in twenty AA patients with active hair loss and fifteen healthy subjects by flow cytometry. The Treg suppressor HLA-DR+ subpopulation was significantly reduced in the patients (P<0.001) and there were significantly fewer cells expressing CD39 among the CD4+CD25+Foxp3+ Treg subpopulation in patients (P = 0.001). FOXP3 CD39 Treg cells were also reduced in hair follicles; by 75% in non-lesional skin and 90% in lesional skin, when compared to control healthy skin. To further characterise Treg cells in AA; Tregs (CD4+CD25+FOXP3+) were investigated for their TCRβ sequence. PCR products analysed by Next Generation Sequencing techniques, showed that all frequent public clonotypes in AA Tregs were also present in controls at relatively similar frequencies, excepting two public clonotypes: CATSRDEGGLDEKLFF (V15 D1 J1-4) and CASRDGTGPSNYGYTF (V2 D1 J1-2), which were exclusively present in controls. This suggests that these Treg clonotypes may have a protective effect and that they may be an exciting subject for future therapeutic applications.

Serum sickness disease in a patient with alopecia areata and Meniere' disease after PRP procedure

BACKGROUND

Platelet rich plasma procedure (PRP) is considered to be one of the safest aesthetic procedures. Adverse reactions after PRP administration are extreme rare.

PURPOSE

We present the patient with serum sickness disease (SSD) after PRP procedure.

OBJECTIVE AND METHODS

41 years old female suffers from alopecia areata for 5 years with frequent relapses and she has been suffering from Menier's disease recurrent symptoms for 6 years. The patient developed SSD after third PRP rejuvenating procedure and she has also noticed new alopecia areata lesions, but without Menier's disease symptoms. After SSD, 4 months later, she developed severe symptoms of Menier's disease with an episode of sudden sensorineural hearing loss. It alleviated only after intravenous administration of methylprednisolone. In our opinion, significant contraindication of PRP procedure is an autoimmune disease in the active phase.