Clinicopathological digital image analyses before and after thermal stimulation subdivide acquired idiopathic generalized anhidrosis into inflammatory and non-inflammatory type.

BACKGROUND: Acquired idiopathic generalized anhidrosis (AIGA) manifests varying degrees of syringotropic inflammation. OBJECTIVE: To better understand the basis of inflammation in AIGA. METHODS: Changes in the extent of cell infiltration around the sweat gland/duct and the difference in the expression level of immune privilege (IP)-related/sweat gland markers before and after thermal stimulation were assessed in AIGA. We also adopted a semi-quantitative digital image analysis of sweating as detected by the starch-iodine method. The changes in sweating before and after treatment was defined as the improvement index. RESULTS: Nine AIGA cases were analyzed. Two cases with minimal inflammation were defined as non-inflammatory type (non-inf)AIGA, while others with evident cell infiltration were defined as inflammatory type (inf)AIGA. MHC class I was significantly upregulated with downregulation of macrophage migration inhibitory factor and alpha-melanocyte-stimulating hormone exclusively in the sweat duct of infAIGA after thermal stimulation (p < 0.05). Furthermore, the extent of inflammation and the ductal dermcidin expression prior to thermal stimulation were inversely correlated (r = - 0.807), while that and the ductal claudin-1 expression after thermal stimulation was positively correlated (r = 0.875). The improvement index positively correlated with the degree of inflammation after thermal stimulation implying possible contribution of inflammation in AIGA pathophysiology. In addition, interferon-induced protein 10 and claudin-1 expression level in the sweat duct before thermal stimulation respectively correlated with the improvement index (r = 0.750, and 0.762). CONCLUSION: The pathophysiology of AIGA may be subcategorized into two groups: IP-collapse possibly play some roles in infAIGA, while ductal dysfunction may exist in non-infAIGA.

Human iPS Cell-Derived Cell Aggregates Exhibited Dermal Papilla Cell Properties in in vitro Three-Dimensional Assemblage Mimicking Hair Follicle Structures.

Current approaches for human hair follicle (HF) regeneration mostly adopt cell-autonomous tissue reassembly in a permissive murine intracorporeal environment. This, together with the limitation in human-derived trichogenic starting materials, potentially hinders the bioengineering of human HF structures, especially for the drug discovery and treatment of hair loss disorders. In this study, we attempted to reproduce the anatomical relationship between an epithelial main body and the dermal papilla (DP) within HF in vitro by three-dimensionally assembling columnarly molded human keratinocytes (KCs) and the aggregates of DP cells and evaluated how HF characteristics were reproduced in the constructs. The replaceability of human-induced pluripotent stem cell (hiPSC)-derived DP substitutes was assessed using the aforementioned reconstruction assay. Human DP cell aggregates were embedded into Matrigel as a cluster. Subsequently, highly condensed human KCs were cylindrically injected onto DP spheroids. After 2-week culture, the structures visually mimicking HFs were obtained. KC-DP constructs partially reproduced HF microanatomy and demonstrated differential keratin (KRT) expression pattern in HFs: KRT14 in the outermost part and KRT13, KRT17, and KRT40, respectively, in the inner portion of the main body. KC-DP constructs tended to upregulate HF-related genes, KRT25, KRT33A, KRT82, WNT5A, and LEF1. Next, DP substitutes were prepared by exposing hiPSC-derived mesenchymal cells to retinoic acid and subsequently to WNT, BMP, and FGF signal activators, followed by cell aggregation. The resultant hiPSC-derived DP substitutes (iDPs) were combined with KCs in the invented assay. KC-iDP constructs morphologically resemble KC-DP constructs and analogously mimicked KRT expression pattern in HF. iDP in the constructs expressed DP-related markers, such as vimentin and versican. Intriguingly, KC-iDP constructs more intensely expressed KRT33A, KRT82, and LEF1, which were stepwisely upregulated by the addition of WNT ligand and the mixture of WNT, SHH, and EDA signaling activators, supporting the idea that iDP exhibited biological properties analogous to DP cell aggregates in the constructs in vitro. These preliminary findings suggested the possibility of regenerating DP equivalents with in vitro hair-inductive capacity using hiPSC-derived cell composites, which potentially reduce the necessity of human tissue-derived trichogenic cell subset and eventually allow xeno-free bioengineering of human HFs.

Digital immunohistological dissection of immune privilege collapse in syringotropic autoimmune diseases: Implication for the pathogenesis.

BACKGROUND: Syringotropic cell infiltration is a histological hallmark of some autoimmune diseases. However, its underlying mechanism remains unclear. OBJECTIVES: To assess the immune privilege (IP) of the human sweat gland (SwG) in homeostasis and in syringotropic autoimmune diseases. METHODS: We combined quantitative digital image microdissection with immunohistochemisty to analyze IP molecule expression in SwG of normal and diseased skin. The human skin organ culture model was used to examine the influence of proinflammatory conditions on IP in SwG. RESULTS: In the normal subjects (n = 10), major histocompatibility complex (MHC) class І expression was significantly reduced in SwGs compared to the epidermis. In contrast, IP-guardians, macrophage migration inhibitory factor (MIF) and alpha-melanocyte stimulating hormone (α-MSH) were upregulated in SwGs. MHC class І was upregulated in whole SwGs in lupus erythematosus (LE; n = 7) and scleroderma/morphea (Scl; n = 9), whereas differential expression was noted only in the secretory portion in Sjögren's syndrome (SjS) (n = 4). MIF expression level inversely correlated with that of MHC class I in all samples tested, and downregulation of α-MSH was detected in LE SwGs alone. The severity of inflammatory changes and MIF and ⍺-MSH expression were inversely correlated in LE. CD200 expression was decreased exclusively in atrophic stage of Scl. In a human skin organ culture model, intratissue injection of interferon-gamma up-regulated MHC class I and downregulated MIF and α-MSH. CONCLUSIONS: These findings indicate that SwGs enjoy IP. Dysregulated IP molecule expression may lead to SwG IP collapse and contribute to distinct inflammatory cell distribution in syringotropic autoimmune disorders.

Intracellular accumulation of PD-1 molecules in circulating T lymphocytes in advanced malignant melanoma: an implication for immune evasion mechanism.

BACKGROUND: The blockade of cell surface PD-1 ((sur)PD-1) by monoclonal antibodies, represented by nivolumab, provides the strategy to treat advanced malignant melanoma (AMM). The intracellular presence of PD-1 molecules have been reported in some T cell subsets, however, their kinetic association with those expressed on the cell surface, let alone their significance in antitumor immunity has been ill-investigated. METHODS: Intracellular PD-1 expression status in T cell subsets in AMM cases during nivolumab administration was chronologically characterized. The kinetics of PD-1 molecules within AMM-derived T cells was assessed in vitro in conjunction with their functional properties. RESULTS: Increase in (sur)PD-1 and intracellular PD-1 ((int)PD-1+) expression was characteristic for AMM T cells. After short-term culture, virtually (sur)PD-1- nivolumab-treated AMM T cells restore (sur)PD-1 expression, which could not be explained by the detachment of nivolumab from PD-1 epitopes alone. The blockade of trans-Golgi network resulted in the decrease in the extent of (sur)PD-1 recovery, suggesting the translocation of accumulated (int)PD-1 to the cell surface. Antigen-specific PD-1+ T cells significantly increased in (int)PD-1+ cells after treatment. In addition, a surge in (int)PD-1+CD4+ T cells was observed prior to the emergence of skin rash as an immune-related adverse event (irAE). CONCLUSIONS: Accumulated (int)PD-1 in T cells may contribute to enhanced immune evasion in AMM. Evaluation of intracellular PD-1 expression would be useful for better management of nivolumab-treated AMM patients in view of predicting treatment response and the incidence of irAE. Our findings further support the necessity of periodical administration of nivolumab for treating AMM.

Monocytes are involved in the balance between regulatory T cells and Th17 cells in severe drug eruptions.

BACKGROUND: Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DiHS/DRESS) is a distinct phenotype of severe drug eruptions characterized by sequential reactivations of herpesviruses. Although a progressive loss of suppressive function in regulatory T cells (Tregs) occurred during the course of DiHS/DRESS, but not in Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), no previous studies investigated the mechanism. Given the recent finding that Treg development could be differentially regulated by CD16+ patrolling monocytes (pMOs) and CD14+ classical monocytes (cMOs), we can hypothesize that a differential fine-tuned interaction between Tregs and monocytes is the driving force behind the possible shift from Tregs to Th17 cells over a prolonged period of time in DiHS/DRESS. OBJECTIVE: To investigate whether the shift from Treg to Th17 could specifically occur during the course of DiHS/DRESS and to elucidate which subsets of monocytes could be involved in the shift. METHODS: We performed a prospective longitudinal study on the frequencies of Tregs, Th17 cells and monocyte subsets after onset of DiHS/DRESS and SJS/TEN, and long after their clinical resolutions. We next examined whether pMOs and cMOs could have a strong impact on the Th17/Treg differentiation and which cytokines could be crucial for the interaction between Th17/Tregs and MO subsets, by in vitro cocultures. RESULTS: Selective depletion of pMOs occurring at the acute stage of DiHS/DRESS was associated with the relative increase in the frequencies of cMOs producing IL-10 and it did drive Treg expansions. After clinical resolution, pMOs producing IL-6 were alternatively recruited and contributed to the eventual shift from a Treg to Th17 responses. CONCLUSIONS AND CLINICAL RELEVANCE: The gradual shift from Treg to Th17 cell development observed during the clinical course of DiHS/DRESS is mediated by the predominance of cMOs at the acute stage and alternatively recruited pMOs at the resolution stage, respectively.

Pathological role of regulatory T cells in the initiation and maintenance of eczema herpeticum lesions.

It remains unknown why the occurrence of eczema herpeticum (EH) caused by an extensive disseminated cutaneous infection with HSV-1 or HSV-2 is associated with the exacerbation of atopic dermatitis lesions after withdrawal of treatment. Although regulatory T cells (Tregs) limit the magnitude of HSV-specific T cell responses in mice, their role in the induction and resolution of EH has not been defined. We initially investigated the frequencies, phenotype, and function of Tregs in the peripheral blood of atopic dermatitis with EH (ADEH) patients at onset and after clinical resolution, atopic dermatitis patients without EH, and healthy controls. Tregs with the skin-homing phenotype and the activated/induced phenotype were expanded at onset and contracted upon resolution. Treg-suppressive capacity was retained in ADEH patients and, the expanded Tregs suppressed IFN-γ production from HSV-1-specific CD8(+) and CD4(+) T cells. The increased frequency of CD14(dim)CD16(+) proinflammatory monocytes (pMOs) was also observed in the blood and EH skin lesions. Thus, pMOs detected in ADEH patients at onset were characterized by an increased ability to produce IL-10 and a decreased ability to produce proinflammatory cytokines, unlike their normal counterparts. Our coculture study using Tregs and pMOs showed that the pMOs can promote the expansion of inducible Tregs. Tregs were detected frequently in the vicinity of HSV-expressing and varicella zoster virus-expressing CD16(+) monocytes in the EH lesions. Expansions of functional Tregs, together with pMOs, initially required for ameliorating excessive inflammation occurring after withdrawal of topical corticosteroids could, in turn, contribute to the initiation and progression of HSV reactivation, resulting in the onset of EH.

Defective regulatory T cells in patients with severe drug eruptions: timing of the dysfunction is associated with the pathological phenotype and outcome.

Toxic epidermal necrolysis (TEN) and drug-induced hypersensitivity syndrome (DIHS) represent two ends of a spectrum of severe drug eruptions: DIHS is unique in that severe epidermal damage seen in TEN is absent, sequential reactivations of herpesviruses occur, and autoimmunity often ensues. To investigate whether changes in regulatory T (Treg) cell function would contribute to variability in the clinical manifestations, we examined the frequency, phenotype, and function of Treg cells both during the acute stage and again long after clinical resolution of both diseases. Dramatic expansions of functional Treg cells were found in the acute stage of DIHS. In contrast, Treg function was profoundly impaired in TEN, although present in normal frequency. Skin homing addressins were more preferentially expressed on Treg cells in DIHS than in TEN. Indeed, Treg cells were more abundantly present in the skin lesions of DIHS. Surprisingly, Treg cells contracted upon resolution of DIHS became functionally deficient, whereas their functional defects in TEN were restored upon recovery. These findings indicate that a transitory impairment in their function during the acute stage of TEN may be related to severe epidermal damage, while a gradual loss of their function after resolution of DIHS may increase the risk of subsequently developing autoimmune disease.

Fucosyltransferase VII-positive, skin-homing T cells in the blood and skin lesions of atopic dermatitis patients.

Patients with atopic dermatitis (AD) have an abnormally increased frequency of cutaneous lymphocyte antigen (CLA)+ Th2 cells responsible for local inflammation; however, this is paradoxical, given the well-recognized defective capacity of Th2 cells to migrate to the skin sites of inflammation. These discrepant observations would stem from the ambiguity of CLA+ T cells, because CLA does not represent the epitope required for binding to E-selectin but the epitope generated by fucosyltransferase VII (Fuc-TVII) and because skin-homing T cells are composed of three distinct subpopulations; Fuc-TVII+ E-selectin ligand (ESL)+ CLA-, Fuc-TVII+ ESL+ CLA+ and Fuc-TVII- ESL- CLA+ cells. We therefore asked which subpopulations of skin-homing Th2 cells could be increased in the blood and skin lesions of AD. We analysed the frequencies of the three subpopulations in purified CD4+ peripheral blood T cells from AD patients and healthy controls by immunohistochemistry and flow cytometry. The Fuc-TVII+ CLA+ or CLA+ ESL+ CCR4+ cells were dramatically increased in frequency not only in the blood but also in the skin lesions of AD patients and this increase was related to the severity of the clinical symptoms. Our data indicate the clinical importance of identifying skin-homing T cells with the potent capacity to migrate into the skin by analysing their Fuc-TVII expression and E-selectin binding ability in patients with AD.

Selective impairment of Toll-like receptor 2-mediated proinflammatory cytokine production by monocytes from patients with atopic dermatitis.

BACKGROUND: The skin of patients with atopic dermatitis (AD) exhibits a striking susceptibility to infection with gram-positive bacteria and herpes simplex virus (HSV), which are known to stimulate Toll-like receptor (TLR) 2. OBJECTIVE: We investigated whether TLR2-mediated proinflammatory cytokine production by monocytes is selectively impaired in patients with AD and, if so, whether high FcvarepsilonRI levels on the monocytes could be related to the impairment. METHODS: The 2 subpopulations of monocytes, CD14(dim) proinflammatory and CD14(bright) classical monocytes, from patients with AD and healthy control subjects were stimulated to produce IL-1beta and TNF-alpha with phorbol 12-myristate 13-acetate/ionomycin, LPS (TLR4 ligand), or Pam3Cys (TLR2 ligand) for 4 hours, and simultaneous flow cytometric assessment of surface phenotype and intracellular cytokine synthesis was performed. Surface expression of TLR2, TLR4, and FcvarepsilonRI on the monocyte subpopulations was also assessed by means of flow cytometry. RESULTS: TLR2-mediated IL-1beta and TNF-alpha production by either the CD14(dim) or CD14(bright) monocytes was found to be selectively impaired in patients with AD. The most remarkable reduction in TLR2-mediated proinflammatory cytokine production was observed in CD14(dim) monocytes expressing high FcvarepsilonRI levels from patients with AD. This reduction was restored by means of downregulation of their FcvarepsilonRI expression after preculture in the absence of IgE. CONCLUSION: Monocytes, particularly the proinflammatory monocytes, from patients with AD are functionally defective in their capacity to produce proinflammatory cytokines on TLR2 stimuli in part because of the high levels of their FcvarepsilonRI expression. CLINICAL IMPLICATIONS: This selective impairment of monocytes would explain why patients with AD are specifically susceptible to cutaneous staphylococcal and streptococcal and HSV infections.

Non-steroidal anti-inflammatory drugs selectively inhibit cytokine production by NK cells and gamma delta T cells.

Non-steroidal anti-inflammatory drugs (NSAIDs) are known to be risk factors for a systemic inflammatory syndrome in viral infections. Innate immune cells are likely to represent the preferential targets for the deleterious effects of NSAIDs in patients with viral infections. We therefore examined whether various classes of NSAIDs could selectively inhibit cytokine production by innate immune cells. NSAIDs selectively inhibited interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production by natural killer (NK) and gammadelta T cells with each NSAID displaying its own unique pattern of inhibition, while sparing that by acquired immune cells. These inhibitions were independent on cyclooxygenase inhibition. These NSAIDs directly inhibited the cytokine production by the purified gammadelta T-cell population without involving other cell populations. The selective inhibition of the early generation of IFN-gamma and TNF-alpha from NK and gammadelta T cells by NSAIDs may serve to drive the subsequent acquired immune responses towards a Th2 phenotype, leading to the aggravation of allergic symptoms. Our results provide a mechanism to explain the deleterious effects of NSAIDs on clinical symptoms of viral infections and allergic diseases and suggest more targeted use depending on the type of disease.

NK cells and gamma delta+ T cells are phenotypically and functionally defective due to preferential apoptosis in patients with atopic dermatitis.

Innate immune cells mediate a first line of defense against pathogens and determine the nature of subsequent acquired immune responses, mainly by producing profound amounts of cytokines. Given these diverse tasks, it is predictable that defective NK and gammadelta(+) T cell responses could be the underlying mechanism for the immunological alterations observed in atopic dermatitis (AD). Indeed, the frequencies of circulating NK cells and gammadelta(+) T cells were profoundly reduced in AD patients. They also displayed a defective ability to sustain TNF-alpha and IFN-gamma, but not IL-4, production after in vitro stimulation, and the defect was restricted to innate immune cells. Surprisingly, on the depletion of CD14(+) monocytes, this selective impairment of TNF-alpha and IFN-gamma production was restored to levels comparable to that observed in controls. Release of IL-10 from monocytes was not a major mechanism of the NK and gammadelta(+) T cell dysfunction. Apoptosis as revealed by annexin V binding, was preferentially observed in NK and gammadelta(+) T cells from AD patients when stimulated in the presence of monocytes, and depletion of monocytes significantly protected these cells from apoptotic cell death. Preferential apoptosis of NK cells by activated monocytes in AD patients was cell-contact-dependent. These results indicate that, once NK and gammadelta(+) T cells in AD patients are in immediate contact with activated monocytes, these cells are specifically targeted for apoptosis, leading to the reduced type 1 cytokine production, thereby directing subsequent acquired immune responses toward a type-2 pattern and increasing susceptibility to infection.