Perivascular leukocyte clusters are essential for efficient activation of effector T cells in the skin.

It remains largely unclear how antigen-presenting cells (APCs) encounter effector or memory T cells efficiently in the periphery. Here we used a mouse contact hypersensitivity (CHS) model to show that upon epicutaneous antigen challenge, dendritic cells (DCs) formed clusters with effector T cells in dermal perivascular areas to promote in situ proliferation and activation of skin T cells in a manner dependent on antigen and the integrin LFA-1. We found that DCs accumulated in perivascular areas and that DC clustering was abrogated by depletion of macrophages. Treatment with interleukin 1α (IL-1α) induced production of the chemokine CXCL2 by dermal macrophages, and DC clustering was suppressed by blockade of either the receptor for IL-1 (IL-1R) or the receptor for CXCL2 (CXCR2). Our findings suggest that the dermal leukocyte cluster is an essential structure for elicitating acquired cutaneous immunity.

Autoimmune disorders associated with gain of function of the intracellular sensor MDA5.

MDA5 is an essential intracellular sensor for several viruses, including picornaviruses, and elicits antiviral interferon (IFN) responses by recognizing viral dsRNAs. MDA5 has been implicated in autoimmunity. However, the mechanisms of how MDA5 contributes to autoimmunity remain unclear. Here we provide direct evidence that dysregulation of MDA5 caused autoimmune disorders. We established a mutant mouse line bearing MDA5 mutation by ENU mutagenesis, which spontaneously developed lupus-like autoimmune symptoms without viral infection. Inflammation was dependent on an adaptor molecule, MAVS indicating the importance of MDA5-signaling. In addition, intercrossing the mutant mice with type I IFN receptor-deficient mice ameliorated clinical manifestations. This MDA5 mutant could activate signaling in the absence of its ligand but was paradoxically defective for ligand- and virus-induced signaling, suggesting that the mutation induces a conformational change in MDA5. These findings provide insight into the association between disorders of the innate immune system and autoimmunity.

Data Resource Profile of Shizuoka Kokuho Database (SKDB) Using Integrated Health- and Care-insurance Claims and Health Checkups: The Shizuoka Study.

BACKGROUND: Analyzing real-world data, including health insurance claims, may help provide insights into preventing and treating various diseases. We developed a database covering Shizuoka Prefecture (Shizuoka Kokuho Database [SKDB]) in Japan, which included individual-level linked data on health- and care-insurance claims and health checkup results. METHODS: Anonymized claims data on health insurance (National Health Insurance [age <75 years] and Latter-Stage Elderly Medical Care System [age ≥75 years]), care insurance, subscriber lists, annual health checkups, and all dates of death were collected from 35 municipalities in Shizuoka Prefecture. To efficiently link claims and health checkups, unique individual IDs were assigned using a novel procedure. RESULTS: From April 2012 to September 2018, the SKDB included 2,230,848 individuals (men, 1,019,687; 45.7%). The median age (min-max) of men and women was 60 (0-106) and 62 (0-111) years, respectively. During the study period, the median subscription time was 4.4 years; 40.8% of individuals continuously subscribed for the 6.5 years; 213,566 individuals died. Health checkup data were available for 654,035 individuals, amounting to 2,469,648 records. Care-service recipient data were available for 283,537 individuals; they used care insurance to pay for care costs. CONCLUSION: SKDB, a population-based longitudinal cohort, provides a comprehensive dataset covering health checkups, disorders, medication, and care service. This database may provide a robust platform to identify epidemiological problems and generate hypotheses for preventing and treating disorders in the elderly.

Assessment of coding-based frailty algorithms for long-term outcome prediction among older people in community settings: a cohort study from the Shizuoka Kokuho Database.

OBJECTIVES: To assess the applicability of Electronic Frailty Index (eFI) and Hospital Frailty Risk Score (HFRS) algorithms to Japanese administrative claims data and to evaluate their association with long-term outcomes. STUDY DESIGN AND SETTING: A cohort study using a regional government administrative healthcare and long-term care (LTC) claims database in Japan 2014-18. PARTICIPANTS: Plan enrollees aged ≥50 years. METHODS: We applied the two algorithms to the cohort and assessed the scores' distributions alongside enrollees' 4-year mortality and initiation of government-supported LTC. Using Cox regression and Fine-Gray models, we evaluated the association between frailty scores and outcomes as well as the models' discriminatory ability. RESULTS: Among 827,744 enrollees, 42.8% were categorised by eFI as fit, 31.2% mild, 17.5% moderate and 8.5% severe. For HFRS, 73.0% were low, 24.3% intermediate and 2.7% high risk; 35 of 36 predictors for eFI, and 92 of 109 codes originally used for HFRS were available in the Japanese system. Relative to the lowest frailty group, the highest frailty group had hazard ratios [95% confidence interval (CI)] of 2.09 (1.98-2.21) for mortality and 2.45 (2.28-2.63) for LTC for eFI; those for HFRS were 3.79 (3.56-4.03) and 3.31 (2.87-3.82), respectively. The area under the receiver operating characteristics curves for the unadjusted model at 48 months was 0.68 for death and 0.68 for LTC for eFI, and 0.73 and 0.70, respectively, for HFRS. CONCLUSIONS: The frailty algorithms were applicable to the Japanese system and could contribute to the identifications of enrollees at risk of long-term mortality or LTC use.

Long-term prognosis and clinical course of choking-induced cardiac arrest in patients without the return of spontaneous circulation at hospital arrival: a population-based community study from the Shizuoka Kokuho Database.

BACKGROUND: The risk of choking increases with aging, and the number of cases of choking-induced cardiac arrest is increasing. However, few studies have examined the prognosis of choking-induced cardiac arrest. The aim of this study was to reveal the rates of survival and dependence on devices in the long term after choking-induced cardiac arrest. METHODS: We analyzed data from the Shizuoka Kokuho Database, which consists of claims data of approximately 2.2 million people, from April 2012 to September 2018. We selected patients with choking-induced cardiac arrest who received cardiopulmonary resuscitation in the hospital. Patients were excluded if they were less than 20 years old, had an upper airway tumor, received ventilation assistance, or received enteral nutrition in the month prior to cardiac arrest. The primary outcome was death, and the secondary outcomes were the rates of survival at 3-months and independence on devices. Descriptive statistics are presented and compared among age groups (20-64 years, 65-74 years, 75-84 years, 85 years and older), and survival time analysis (Kaplan-Meier method) was performed. RESULTS: In total, 268 patients were analyzed, including 26 patients in the 20-64 age group, 33 patients in the 65-74 age group, 70 patients in the 75-84 age group, and 139 patients in the ≥85 age group. The overall 3-month survival rate was 5.6% (15/268). The 3-month survival rates were 3.8% (1/26) in the 20-64 age group, 15.2% (5/33) in the 65-74 age group, 8.6% (6/70) in the 75-84 age group, and 2.2% (3/139) in the ≥85 age group. The overall 12-month survival rate was 2.6% (7/268). Of the 7 patients who survived for 12 months, 3 received ventilation management and 5 received tube or intravenous feedings at 3 months. These survivors were still receiving ventilation assistance and tube feedings in the hospital and had not been discharged at 12 months. CONCLUSIONS: The prognosis of choking-induced cardiac arrest was extremely poor when patients were not resuscitated before hospital arrival. Those who survived were mostly dependent on assistive devices. Additionally, none of the survivors dependent on assistive devices had discontinued the use of the devices at the long-term follow-up.

Guideline for the diagnosis, treatment and long-term management of cutaneous lupus erythematosus.

Cutaneous lupus erythematosus (CLE) is an inflammatory, autoimmune disease encompassing a broad spectrum of subtypes including acute, subacute, chronic and intermittent CLE. Among these, chronic CLE can be further classified into several subclasses of lupus erythematosus (LE) such as discoid LE, verrucous LE, LE profundus, chilblain LE and Blaschko linear LE. To provide all dermatologists and rheumatologists with a practical guideline for the diagnosis, treatment and long-term management of CLE, this evidence- and consensus-based guideline was developed following the checklist established by the international Reporting Items for Practice Guidelines in Healthcare (RIGHT) Working Group and was registered at the International Practice Guideline Registry Platform. With the joint efforts of the Asian Dermatological Association (ADA), the Asian Academy of Dermatology and Venereology (AADV) and the Lupus Erythematosus Research Center of Chinese Society of Dermatology (CSD), a total of 25 dermatologists, 7 rheumatologists, one research scientist on lupus and 2 methodologists, from 16 countries/regions in Asia, America and Europe, participated in the development of this guideline. All recommendations were agreed on by at least 80% of the 32 voting physicians. As a consensus, diagnosis of CLE is mainly based on the evaluation of clinical and histopathological manifestations, with an exclusion of SLE by assessment of systemic involvement. For localized CLE lesions, topical corticosteroids and topical calcineurin inhibitors are first-line treatment. For widespread or severe CLE lesions and (or) cases resistant to topical treatment, systemic treatment including antimalarials and (or) short-term corticosteroids can be added. Notably, antimalarials are the first-line systemic treatment for all types of CLE, and can also be used in pregnant patients and pediatric patients. Second-line choices include thalidomide, retinoids, dapsone and MTX, whereas MMF is third-line treatment. Finally, pulsed-dye laser or surgery can be added as fourth-line treatment for localized, refractory lesions of CCLE in cosmetically unacceptable areas, whereas belimumab may be used as fourth-line treatment for widespread CLE lesions in patients with active SLE, or recurrence of ACLE during tapering of corticosteroids. As for management of the disease, patient education and a long-term follow-up are necessary. Disease activity, damage of skin and other organs, quality of life, comorbidities and possible adverse events are suggested to be assessed in every follow-up visit, when appropriate.

Real-World Evidence of the Incidence of and Risk Factors for Type 1 Diabetes Mellitus and Hypothyroidism as Immune-Related Adverse Events Associated With Programmed Cell Death-1 Inhibitors.

OBJECTIVE: The incidence of type 1 diabetes mellitus (T1DM) and hypothyroidism as immune-related adverse events (irAEs) after programmed cell death-1 inhibitor (PD-1i) administration has not yet been sufficiently evaluated in a real clinical setting. To assess the incidence of T1DM and hypothyroidism among PD-1is and to identify the risk factors associated with hypothyroidism using a large claims database. METHODS: This cohort study used the Shizuoka Kokuho database in Japan from 2012 to 2018, including approximately 2.2 million people. We enrolled 695 PD-1i-treated patients. T1DM and hypothyroidism as irAEs were identified using International Classification of Diseases 10th Revision and Anatomical Therapeutic Chemical classification codes. Risk factors for hypothyroidism were explored using the multivariable Fine and Gray regression model after adjusting for age group and sex, treating death as a competing risk. RESULTS: The cumulative incidences of T1DM and hypothyroidism were 0.3% and 8.3%, respectively. We described the detailed onset timing of irAEs in patients with T1DM and hypothyroidism; hypothyroidism was observed evenly within 1 year of the PD-1i prescription. Sex and certain cancer types, such as lung and urothelial cancers, were significantly associated with subdistribution hazard ratio (sHR) (female: sHR, 2.04 [95% CI, 1.20-3.47]; lung cancer: sHR, 0.55 [95% CI, 0.32-0.95]; and urothelial carcinoma: sHR, 2.40 [95% CI, 1.05-5.49]). CONCLUSION: The incidence of T1DM and hypothyroidism as irAEs and associated risk factors identified in this analysis were comparable to those found in previous studies. The use of a large claims database to detect irAEs, such as T1DM and hypothyroidism, may lead to safer use of PD-1is.

Inhibition of IL-17-committed T cells in a murine psoriasis model by a vitamin D analogue.

BACKGROUND: A better understanding of the means by which topical vitamin D analogues exert their therapeutic effect on psoriasis is of theoretical and practical importance. OBJECTIVE: We sought to clarify whether and how the topical vitamin D analogue calcipotriol (CAL) controls the IL-17A-mediated pathogenesis of murine psoriasis-like dermatitis in vivo. METHODS: Psoriasis-like dermatitis was induced by the topical application of an imiquimod (IMQ)-containing cream on the murine ear for 4 to 6 consecutive days. For topical CAL treatment, mice were treated daily with CAL solution on the ear before IMQ application. RESULTS: Mice treated topically with CAL exhibited much milder IMQ-induced psoriasis-like dermatitis compared with vehicle-treated mice, with impaired accumulation of IL-17A-committed T (T17) cells in the lesional skin. The IMQ-induced upregulation of Il12b and Il23a was marked in the epidermis and was abrogated by CAL application, suggesting CAL-mediated suppression of IL-23 expression. CAL inhibited Il12b and Il23a expression by Langerhans cells ex vivo stimulated with IMQ and CD40 cross-linking. Topical CAL also inhibited T17 cell expansion in the draining lymph nodes of IMQ-treated skin, implying a possible effect on T17 cell-mediated dermatitis at distant sites. In fact, topical CAL application on the IMQ-treated left ear resulted in amelioration of T17 cell accumulation and psoriasis-like dermatitis in the right ear subsequently treated with IMQ. CONCLUSION: Topical CAL can exert its antipsoriatic effect on CAL-treated lesions and, concomitantly, distant lesions by attenuating the T17 cell accumulation in both CAL-treated lesions and draining lymph nodes.

Indispensable role of the Runx1-Cbfbeta transcription complex for in vivo-suppressive function of FoxP3+ regulatory T cells.

Naturally arising regulatory T (Treg) cells express the transcription factor FoxP3, which critically controls the development and function of Treg cells. FoxP3 interacts with another transcription factor Runx1 (also known as AML1). Here, we showed that Treg cell-specific deficiency of Cbfbeta, a cofactor for all Runx proteins, or that of Runx1, but not Runx3, induced lymphoproliferation, autoimmune disease, and hyperproduction of IgE. Cbfb-deleted Treg cells exhibited impaired suppressive function in vitro and in vivo, with altered gene expression profiles including attenuated expression of FoxP3 and high expression of interleukin-4. The Runx complex bound to more than 3000 gene loci in Treg cells, including the Foxp3 regulatory regions and the Il4 silencer. In addition, knockdown of RUNX1 showed that RUNX1 is required for the optimal regulation of FoxP3 expression in human T cells. Taken together, our results indicate that the Runx1-Cbfbeta heterodimer is indispensable for in vivo Treg cell function, in particular, suppressive activity and optimal expression of FoxP3.

Regulatory T Cells in Melanoma Revisited by a Computational Clustering of FOXP3+ T Cell Subpopulations.

CD4(+) T cells that express the transcription factor FOXP3 (FOXP3(+) T cells) are commonly regarded as immunosuppressive regulatory T cells (Tregs). FOXP3(+) T cells are reported to be increased in tumor-bearing patients or animals and are considered to suppress antitumor immunity, but the evidence is often contradictory. In addition, accumulating evidence indicates that FOXP3 is induced by antigenic stimulation and that some non-Treg FOXP3(+) T cells, especially memory-phenotype FOXP3(low) cells, produce proinflammatory cytokines. Accordingly, the subclassification of FOXP3(+) T cells is fundamental for revealing the significance of FOXP3(+) T cells in tumor immunity, but the arbitrariness and complexity of manual gating have complicated the issue. In this article, we report a computational method to automatically identify and classify FOXP3(+) T cells into subsets using clustering algorithms. By analyzing flow cytometric data of melanoma patients, the proposed method showed that the FOXP3(+) subpopulation that had relatively high FOXP3, CD45RO, and CD25 expressions was increased in melanoma patients, whereas manual gating did not produce significant results on the FOXP3(+) subpopulations. Interestingly, the computationally identified FOXP3(+) subpopulation included not only classical FOXP3(high) Tregs, but also memory-phenotype FOXP3(low) cells by manual gating. Furthermore, the proposed method successfully analyzed an independent data set, showing that the same FOXP3(+) subpopulation was increased in melanoma patients, validating the method. Collectively, the proposed method successfully captured an important feature of melanoma without relying on the existing criteria of FOXP3(+) T cells, revealing a hidden association between the T cell profile and melanoma, and providing new insights into FOXP3(+) T cells and Tregs.

The first nationwide surveillance of antibacterial susceptibility patterns of pathogens isolated from skin and soft-tissue infections in dermatology departments in Japan.

To investigate the trends of antimicrobial resistance in pathogens isolated from skin and soft-tissue infections (SSTI) at dermatology departments in Japan, a Japanese surveillance committee conducted the first nationwide survey in 2013. Three main organisms were collected from SSTI at 30 dermatology departments in medical centers and 10 dermatology clinics. A total of 860 strains - 579 of Staphylococcus aureus, 240 of coagulase-negative Staphylococci, and 41 of Streptococcus pyogenes - were collected and shipped to a central laboratory for antimicrobial susceptibility testing. The patient profiles were also studied. Among all 579 strains of S. aureus, 141 (24.4%) were methicillin-resistant (MRSA). Among 97 Staphylococcus epidermidis strains, 54 (55.7%) were methicillin-resistant (MRSE). MRSA and MRSE were more frequently isolated from inpatients than from outpatients. Furthermore, these methicillin-resistant strains were also isolated more frequently from patients with histories of taking antibiotics within 4 weeks and hospitalization within 1 year compared to those without. However, there were no significant differences in MIC values and susceptibility patterns of the MRSA strains between patients with a history of hospitalization within 1 year and those without. Therefore, most of the isolated MRSA cases at dermatology departments are not healthcare-acquired, but community-acquired MRSA. S. pyogenes strains were susceptible to most antibiotics except macrolides. The information in this study is not only important in terms of local public health but will also contribute to an understanding of epidemic clones of pathogens from SSTI.

The Janus kinase inhibitor JTE-052 improves skin barrier function through suppressing signal transducer and activator of transcription 3 signaling.

BACKGROUND: Barrier disruption and the resulting continuous exposure to allergens are presumed to be responsible for the development of atopic dermatitis (AD). However, the mechanism through which skin barrier function is disrupted in patients with AD remains unclear. OBJECTIVES: Taking into account the fact that the TH2 milieu impairs keratinocyte terminal differentiation, we sought to clarify our hypothesis that the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway plays a critical role in skin barrier function and can be a therapeutic target for AD. METHODS: We analyzed the mechanism of keratinocyte differentiation using a microarray and small interfering RNA targeting STATs. We studied the effect of the JAK inhibitor JTE-052 on keratinocyte differentiation using the human skin equivalent model and normal human epidermal keratinocytes. We applied topical JAK inhibitor onto NC/Nga mice, dry skin model mice, and human skin grafted to immunocompromised mice. RESULTS: IL-4 and IL-13 downregulated genes involved in keratinocyte differentiation. STAT3 and STAT6 are involved in keratinocyte differentiation and chemokine production by keratinocytes, respectively. Topical application of the JAK inhibitor suppressed STAT3 activation and improved skin barrier function, permitting increases in levels of terminal differentiation proteins, such as filaggrin, and natural moisturizing factors in models of AD and dry skin and in human skin. CONCLUSION: STAT3 signaling is a key element that regulates keratinocyte differentiation. The JAK inhibitor can be a new therapeutic tool for the treatment of disrupted barrier function in patients with AD.

Generation of Helios reporter mice and an evaluation of the suppressive capacity of Helios(+) regulatory T cells in vitro.

Helios is a member of the Ikaros transcription factor family and has been reported to be a marker of thymus-derived regulatory T cells (Treg). Helios is an intracellular protein, however, and hence cannot be used as a marker to separate living Tregs. To solve this problem, we generated Helios reporter mice in which Helios+ cells selectively express Venus, a variant of green fluorescent protein. Most of the Tregs in the thymus expressed Helios, whereas its expression was varied in peripheral lymphoid organs. The Helios+ Treg-population was superior in ability to suppress both antigen-specific and TCR-stimulated T cell responses. We also showed that Helios+ Tregs inhibited the cytokine production by T cells more efficiently than Helios- Tregs. We conclude that Helios reporter mouse strain is a useful tool to study function of Helios and that Helios+ Tregs represent the highly suppressive population.

Clinical epidemiology of eosinophilic pustular folliculitis: results from a nationwide survey in Japan.

BACKGROUND: No epidemiological study has examined the clinical characteristics, including medication use, of patients with eosinophilic pustular folliculitis (EPF). OBJECTIVE: To describe the clinical characteristics for EPF and to examine the factors associated with the effectiveness of oral indomethacin for EPF. METHODS: A cross-sectional study was performed of patients with EPF who visited the dermatology departments of the 67 main teaching facilities in Japan. We documented the patient characteristics and examined factors associated with the effectiveness of oral indomethacin. RESULTS: A total of 145 patients with EPF were enrolled; 62.8% were prescribed oral indomethacin. A multivariable analysis revealed that female patients were more likely to exhibit complete response to oral indomethacin after adjustment for confounders (adjusted proportion ratio = 1.93, p = 0.04). CONCLUSION: Oral indomethacin has been accepted as a first-line treatment in EPF. Our results suggest that there is a sex difference in the treatment response to oral indomethacin.

Comparison of the efficacy of olopatadine and fexofenadine in chronic idiopathic urticaria patients: a crossover study.

Olopatadine is one of the second-generation H1 antihistamines that were used for treating allergic disorders initially in Asia, and now also in Western countries. Whereas several trials compared the efficacy on chronic urticaria among second-generation H1 antihistamines, no study has directly compared the clinical efficacy between olopatadine and other H1 antihistamines in patients with chronic idiopathic urticaria (CIU). In this study, we address this issue for the first time and conclude that olopatadine is a good candidate for the treatment of CIU.

Possible new therapeutic strategy to regulate atopic dermatitis through upregulating filaggrin expression.

BACKGROUND: Nonsense mutations in filaggrin (FLG) represent a significant genetic factor in the cause of atopic dermatitis (AD). OBJECTIVE: It is of great importance to find drug candidates that upregulate FLG expression and to determine whether increased FLG expression controls the development of AD. METHODS: We screened a library of bioactives by using an FLG reporter assay to find candidates that promoted FLG mRNA expression using a human immortalized keratinocyte cell line (HaCaT). We studied the effect of the compound on keratinocytes using the human skin equivalent model. We examined the effect of the compound on AD-like skin inflammation in NC/Nga mice. RESULTS: JTC801 promoted FLG mRNA and protein expression in both HaCaT and normal human epidermal keratinocytes. Intriguingly, JTC801 promoted the mRNA and protein expression levels of FLG but not the mRNA levels of other makers for keratinocyte differentiation, including loricrin, keratin 10, and transglutaminase 1, in a human skin equivalent model. In addition, oral administration of JTC801 promoted the protein level of Flg and suppressed the development of AD-like skin inflammation in NC/Nga mice. CONCLUSION: This is the first observation that the compound, which increased FLG expression in human and murine keratinocytes, attenuated the development of AD-like skin inflammation in mice. Our findings provide evidence that modulation of FLG expression can be a novel therapeutic target for AD.

Basophils regulate the recruitment of eosinophils in a murine model of irritant contact dermatitis.

BACKGROUND: Although eosinophils have been detected in several human skin diseases in the vicinity of basophils, how eosinophils infiltrate the skin and the role of eosinophils in the development of skin inflammation have yet to be examined. OBJECTIVE: Using murine irritant contact dermatitis (ICD) as a model, we sought to clarify the roles of eosinophils in ICD and the underlying mechanism of eosinophil infiltration of the skin. METHODS: We induced croton oil-induced ICD in eosinophil-deficient ΔdblGATA mice with or without a reactive oxygen species (ROS) inhibitor. We performed cocultivation with fibroblasts and bone marrow-derived basophils and evaluated eosinophil migration using a chemotaxis assay. RESULTS: ICD responses were significantly attenuated in the absence of eosinophils or by treatment with the ROS inhibitor. ROS was produced abundantly by eosinophils, and both basophils and eosinophils were detected in human and murine ICD skin lesions. In coculture experiments, basophils attracted eosinophils, especially in the presence of fibroblasts. Moreover, basophils produced IL-4 and TNF-α in contact with fibroblasts and promoted the expression of eotaxin/CCL11 from fibroblasts in vitro. CONCLUSION: Eosinophils mediated the development of murine ICD, possibly through ROS production. Recruitment of eosinophils into the skin was induced by basophils in cooperation with fibroblasts. Our findings introduce the novel concept that basophils promote the recruitment of eosinophils into the skin through fibroblasts in the development of skin inflammation.

CD8⁺ tumor-infiltrating lymphocytes at primary sites as a possible prognostic factor of cutaneous angiosarcoma.

Tumor-infiltrating lymphocytes (TILs) have been reported as a prognostic factor in various cancers and are a promising target for immunotherapy. To investigate whether TILs have any impact on the prognosis of angiosarcoma patients, 55 non-treated patients (40 patients at stage 1 with cutaneous localized tumors, 4 patients at stage 2 with lymph node metastases and 11 patients at stage 3 with distant metastases) with angiosarcoma were evaluated retrospectively by immunohistochemistry stained CD4, CD8, FOXP3 and Ki67. The Kaplan-Meier method was used to estimate overall survival with patients at stage 1. Survival differences were analyzed by the log-rank test. Patients with higher numbers of CD8(+) TILs in their primary tumors survived significantly longer compared with patients with lower values. Moreover, the number of CD8 in TILs was positively correlated with a distant metastasis-free period. The total number of primary TILs (CD4 plus CD8) and CD8(+) primary TILs of stage 3 patients with distant metastases was positively correlated with their overall survival. To evaluate whether CD8(+) effector T cells are activated or differentiated, flow cytometric analysis of peripheral blood mononuclear cells (PBMC) was performed. The percentages of CD8(+) T cells producing IFN-γ in PBMC were significantly higher in patients with angiosarcoma (n = 10) compared not only with that of healthy controls (n = 20) but also patients with advanced melanoma (n = 11). These results suggest that anti-tumor immunity is clinically relevant in angiosarcoma.