Search

Immune checkpoint inhibitors improved the survival rate of patients with unresectable melanoma. However, some patients do not respond, and variable immune-related adverse events have been reported. Therefore, more effective and antigen-specific immune therapies are urgently needed. We previously reported the efficacy of an immune cell therapy with immortalized myeloid cells derived from induced pluripotent stem cells (iPS-ML). In this study, we generated OX40L-overexpressing iPS-ML (iPS-ML-Zsgreen-OX40L) and investigated their characteristics and in vivo efficacy against mouse melanoma. We found that iPS-ML-Zsgreen-OX40L suppressed the progression of B16-BL6 melanoma, and prolonged survival of mice with ovalbumin (OVA)-expressing B16 melanoma (MO4). The number of antigen-specific CD8+ T cells was higher in spleen cells treated with OVA peptide-pulsed iPS-ML-Zsgreen-OX40L than in those without OX40L. The OVA peptide-pulsed iPS-ML-Zsgreen-OX40L significantly increased the number of tumor-infiltrating T lymphocytes (TILs) in MO4 tumor. Flow cytometry showed decreased regulatory T cells but increased effector and effector memory T cells among the TILs. Although we plan to use allogeneic iPS-ML in the clinical applications, iPS-ML showed the tumorgenicity in the syngeneic mice model. Incorporating the suicide gene is necessary to ensure the safety in the future study. Collectively, these results indicate that iPS-ML-Zsgreen-OX40L therapy might be a new method for antigen-specific cancer immunotherapy.

The multinational phase 3 CheckMate 238 trial compared adjuvant therapy with nivolumab versus ipilimumab among patients with resected stage III or IV melanoma (N = 906). In this Japanese subgroup analysis of CheckMate 238 (n = 28; nivolumab, n = 18; ipilimumab, n = 10), both the 12‐ and 18‐month recurrence‐free survival rates were 56% for nivolumab and 30% for ipilimumab (hazard ratio, 0.66; 97.56% confidence interval, 0.19–2.24; P = 0.4390). No new safety signals were reported for Japanese patients. Results were consistent with those from the CheckMate 238 global population, indicating that nivolumab has the potential to be a treatment option for Japanese patients with resected melanoma who are at high risk of recurrence.

Background Immune checkpoint inhibitors (ICIs) have a lower efficacy in mucosal melanoma (MUM) than in cutaneous melanoma. The use of combination treatments with radiotherapy (RT) to improve the efficacy in MUM, however, requires further investigation. Methods We retrospectively evaluated 225 advanced MUM patients treated with anti-PD-1 monotherapy (PD1; 115) or anti-PD-1 + anti-CTLA-4 combination therapy (PD1+CTLA4; 42) with or without RT (56 and 12, respectively). Treatment efficacy was estimated by determining the objective response rate (ORR) and survival rate with the Kaplan–Meier analysis. Results The baseline characteristics between the two groups in each ICI cohort were similar, except for Eastern Cooperative Oncology Group performance status in the PD1 cohort. No significant differences in ORR, progression-free survival (PFS), and overall survival (OS) were observed between the PD1 alone and PD1+RT groups in the PD1 cohort (ORR 26% versus 27%, P > 0.99; median PFS 6.2 versus 6.8 months, P = 0.63; median OS 19.2 versus 23.1 months, P = 0.70) or between the PD1+CTLA alone and PD1+CTLA4+RT groups in the PD1+CTLA4 cohort (ORR 28% vs 25%, P = 0.62; median PFS 5.8 versus 3.5 months, P = 0.21; median OS 31.7 versus 19.8 months, P = 0.79). Cox multivariate analysis indicated that RT in addition to PD1 or PD1+CTLA4 did not have a positive impact on the PFS or OS. Conclusions A prolonged survival benefit with RT in combination with ICIs was not identified for advanced MUM patients, although RT may improve local control of the tumour and relieve local symptoms.

With consideration of the ongoing developments in treatment options for cutaneous melanoma, the Japanese Skin Cancer Society published the first guidelines for cutaneous melanoma in 2007 and later revised them in 2015. Here, we report on an English version of the 2019 Japanese Melanoma Guidelines. In this latest edition, all processes were carried out according to the Grading of Recommendations, Assessment, Development and Evaluation system. A comprehensive published work search, systematic review and determination of recommendations in each clinical question were performed by a multidisciplinary expert panel consisting of dermatologists, a plastic and reconstructive surgeon, and a radiation oncologist. The advent of novel agents, such as immune checkpoint inhibitors and molecular-targeted agents, has drastically changed the nature of treatment for adjuvant and advanced-stage diseases among melanoma patients worldwide. Additionally, recent reports of clinical trials regarding surgical procedures and a better understanding of molecular biology and tumor immunology in clinical types of melanoma have had an impact on clinical practise. Based on these viewpoints, eight relevant clinical questions were raised in this report that aim to help clinicians select the appropriate therapeutic approach.

Major histocompatibility complex class I loss due to the abnormality of β2-microglobulin gene is one of the mechanisms underlying delayed relapses in melanoma patients long after the initial positive responses to anti-PD-1 therapy. However, the tumor-specific reactivity of tumor-infiltrating lymphocytes in tumor lesions that lost major histocompatibility complex class I expression has not been well evaluated. We report the case of a 55-year-old woman with two metastatic melanoma lesions. After a 12-month period of successful tumor suppression by anti-PD-1 antibody therapy, one lesion started to grow again. We resected both lesions and examined the tumor cells and tumor-infiltrating lymphocytes. The shrinking lesion consisted of necrotic tissue and macrophages, and the enlarged lesion consisted of both necrotic tissue and viable tumor cells. The tumor cells completely lost major histocompatibility complex class I expression, but it was restored upon retroviral transduction of the normal β2-microglobulin gene. When we checked the tumor-specific reactivity of tumor-infiltrating lymphocytes derived from the relapsing lesion, we found that these tumor-infiltrating lymphocytes failed to recognize the native tumor cells derived from the lesion, but strongly recognized the major histocompatibility complex class-I-recovered cells by β2-microglobulin transduction. Our report emphasizes the limitations of T-cell-based immunotherapy and highlights the importance of developing alternative strategies for such cases.

Background: The European Organisation for Research and Treatment of Cancer (EORTC) 1325/KEYNOTE-054 trial assessed pembrolizumab versus placebo in patients with resected high-risk stage III melanoma. At 15-month median follow-up, pembrolizumab improved recurrence-free survival (hazard ratio [HR] 0·57 [98·4% CI 0·43–0·74], p1 mm), IIIB, or IIIC (without in-transit metastasis), and with an Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible. Patients were randomly assigned (1:1) via a central interactive voice response system to receive intravenous pembrolizumab 200 mg or placebo every 3 weeks for up to 18 doses or until disease recurrence or unacceptable toxicity. Randomisation was stratified according to disease stage and region, using a minimisation technique, and clinical investigators, patients, and those collecting or analysing the data were masked to treatment assignment. The two coprimary endpoints were recurrence-free survival in the intention-to-treat (ITT) population and in patients with PD-L1-positive tumours. The secondary endpoint reported here was distant metastasis-free survival in the ITT and PD-L1-positive populations. This study is registered with ClinicalTrials.gov, NCT02362594, and EudraCT, 2014-004944-37. Findings: Between Aug 26, 2015, and Nov 14, 2016, 1019 patients were assigned to receive either pembrolizumab (n=514) or placebo (n=505). At an overall median follow-up of 42·3 months (IQR 40·5–45·9), 3·5-year distant metastasis-free survival was higher in the pembrolizumab group than in the placebo group in the ITT population (65·3% [95% CI 60·9–69·5] in the pembrolizumab group vs 49·4% [44·8–53·8] in the placebo group; HR 0·60 [95% CI 0·49–0·73]; p

We have established an immune cell therapy with immortalized induced pluripotent stem-cell–derived myeloid lines (iPS-ML). The benefits of using iPS-ML are the infinite proliferative capacity and ease of genetic modification. In this study, we introduced 4-1BBL gene to iPS-ML (iPS-ML-41BBL). The analysis of the cell-surface molecules showed that the expression of CD86 was upregulated in iPS-ML-41BBL more than that in control iPS-ML. Cytokine array analysis was performed using supernatants of the spleen cells that were cocultured with iPS-ML or iPS-ML-41BBL. Multiple cytokines that are beneficial to cancer immunotherapy were upregulated. Peritoneal injections of iPS-ML-41BBL inhibited tumor growth of peritoneally disseminated mouse melanoma and prolonged survival of mice compared to that of iPS-ML. Furthermore, the numbers of antigen-specific CD8+ T cells were significantly increased in the spleen and tumor tissues treated with epitope peptide-pulsed iPS-ML-41BBL compared to those treated with control iPS-ML. The number of CXCR6-positive T cells were increased in the tumor tissues after treatment with iPS-ML-41BBL compared to that with control iPS-ML. These results suggest that iPS-ML-41BBL could activate antigen-specific T cells and promote their infiltration into the tumor tissues. Thus, iPS-ML-41BBL may be a candidate for future immune cell therapy aiming to change immunological “cold tumor” to “hot tumor”.

PD-1 blockade exerts clinical efficacy against various types of cancer by reinvigorating T cells that directly attack tumor cells (tumor-specific T cells) in the tumor microenvironment (TME), and tumor-infiltrating lymphocytes (TILs) also comprise nonspecific bystander T cells. Here, we show that TILs include skewed T cell clonotypes, which are characterized by exhaustion (Tex) or nonexhaustion signatures (Tnon-ex), using single-cell sequencing. Among skewed clonotypes, those in the Tex, but not those in the Tnon-ex, cluster responded to autologous tumor cell lines. After PD-1 blockade, new tumor-specific clonotypes in the Tex cluster appeared in the TME. Tumor-draining lymph nodes (TDLNs) without metastasis harbor a considerable number of such clonotypes, whereas these clonotypes are rarely detected in peripheral blood. We propose that tumor-infiltrating skewed T cell clonotypes with an exhausted phenotype directly attack tumor cells and that PD-1 blockade can promote novel infiltration of tumor-specific T-cell clonotypes, mainly from TDLNs.

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is one of the important molecules that regulate the anti-melanoma T-cell response. Currently, there are some reports showing that CTLA-4 is expressed not only by T cells but also by various kinds of tumor cells, including melanoma cells. However, there is no report that shows the role of CTLA-4 expressed by melanoma cells in melanoma-specific cytotoxic T-lymphocyte (CTL) response. In this report, we confirmed substantial CTLA-4 expression and the localization of CTLA-4 in melanoma cell lines and tissues. Also, we examined its impact on melanoma-specific CTL in vitro, and found that CTLA-4 expressed by melanoma cells does not affect melanoma-specific CTL in the effector phase. Our findings suggest the importance of elucidating the role of CTLA-4 expressed by melanoma cells, particularly in anti-CTLA-4 antibody therapy.

Background Anti-programmed cell death protein 1 (PD-1) antibody monotherapy (PD1) has led to favorable responses in advanced non-acral cutaneous melanoma among Caucasian populations; however, recent studies suggest that this therapy has limited efficacy in mucosal melanoma (MCM). Thus, advanced MCM patients are candidates for PD1 plus anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) combination therapy (PD1 + CTLA4). Data on the efficacy of immunotherapy in MCM, however, are limited. We aimed to compare the efficacies of PD1 and PD1 + CTLA4 in Japanese advanced MCM patients. Patients and methods We retrospectively assessed advanced MCM patients treated with PD1 or PD1 + CTLA4 at 24 Japanese institutions. Patient baseline characteristics, clinical responses (RECIST), progression-free survival (PFS), and overall survival (OS) were estimated using Kaplan–Meier analysis, and toxicity was assessed to estimate the efficacy and safety of PD1 and PD1 + CTLA4. Results Altogether, 329 patients with advanced MCM were included in this study. PD1 and PD1 + CTLA4 were used in 263 and 66 patients, respectively. Baseline characteristics were similar between both treatment groups, except for age (median age 71 versus 65 years; P < 0.001). No significant differences were observed between the PD1 and PD1 + CTLA4 groups with respect to objective response rate (26% versus 29%; P = 0.26) or PFS and OS (median PFS 5.9 months versus 6.8 months; P = 0.55, median OS 20.4 months versus 20.1 months; P = 0.55). Cox multivariate survival analysis revealed that PD1 + CTLA4 did not prolong PFS and OS (PFS: hazard ratio 0.83, 95% confidence interval 0.58-1.19, P = 0.30; OS: HR 0.89, 95% confidence interval 0.57-1.38, P = 0.59). The rate of ≥grade 3 immune-related adverse events was higher in the PD1 + CTLA4 group than in the PD1 group (53% versus 17%; P < 0.001). Conclusions First-line PD1 + CTLA4 demonstrated comparable clinical efficacy to PD1 in Japanese MCM patients, but with a higher rate of immune-related adverse events., Highlights • Anti-PD-1 plus anti-CTLA-4 antibody therapy (PD1 + CTLA4) is an option for patients with advanced mucosal melanoma (MCM). • Data on the efficacy of PD1 + CTLA4 compared with PD-1 monotherapy (PD1) for MCM, however, are limited. • We retrospectively analyzed data from 329 Japanese patients with advanced MCM treated with PD1 or PD1 + CTLA4. • No significant differences in objective response rate, progression-free survival, or overall survival were observed. • Immune-related adverse events resulting in treatment cessation were higher in the PD1 + CTLA4 group.

BackgroundPatients with cancer benefit from treatment with immune checkpoint inhibitors (ICIs), and those with an inflamed tumor microenvironment (TME) and/or high tumor mutation burden (TMB), particularly, tend to respond to ICIs; however, some patients fail, whereas others acquire resistance after initial response despite the inflamed TME and/or high TMB. We assessed the detailed biological mechanisms of resistance to ICIs such as programmed death 1 and/or cytotoxic T-lymphocyte-associated protein 4 blockade therapies using clinical samples.MethodsWe established four pairs of autologous tumor cell lines and tumor-infiltrating lymphocytes (TILs) from patients with melanoma treated with ICIs. These tumor cell lines and TILs were subjected to comprehensive analyses and in vitro functional assays. We assessed tumor volume and TILs in vivo mouse models to validate identified mechanism. Furthermore, we analyzed additional clinical samples from another large melanoma cohort.ResultsTwo patients were super-responders, and the others acquired resistance: the first patient had a non-inflamed TME and acquired resistance due to the loss of the beta-2 microglobulin gene, and the other acquired resistance despite having inflamed TME and extremely high TMB which are reportedly predictive biomarkers. Tumor cell line and paired TIL analyses showed high CD155, TIGIT ligand, and TIGIT expression in the tumor cell line and tumor-infiltrating T cells, respectively. TIGIT blockade or CD155-deletion activated T cells in a functional assay using an autologous cell line and paired TILs from this patient. CD155 expression increased in surviving tumor cells after coculturing with TILs from a responder, which suppressed TIGIT+T-cell activation. Consistently, TIGIT blockade or CD155-deletion could aid in overcoming resistance to ICIs in vivo mouse models. In clinical samples, CD155 was related to resistance to ICIs in patients with melanoma with an inflamed TME, including both primary and acquired resistance.ConclusionsThe TIGIT/CD155 axis mediates resistance to ICIs in patients with melanoma with an inflamed TME, promoting the development of TIGIT blockade therapies in such patients with cancer.

Background The programmed cell death-1 (PD-1)/programmed death ligand 1 (PD-L1) pathway is known to inhibit the activation of effector CD8+ T cells. However, just how this regulatory pathway is involved in the pathophysiology of CD8+ T-cell–mediated inflammatory skin diseases remains unclear. Objective Our aim was to elucidate the mechanisms by which the PD-1/PD-L1 pathway exerts its regulatory roles in CD8+ T-cell–mediated cutaneous immune responses. Methods PD-L1–deficient (Pdl1–/–) mice were used for the murine contact hypersensitivity model. Inflammatory responses such as IFN-γ production from CD8+ T cells in the skin was evaluated by flow cytometry. Results Compared with wild-type mice, Pdl1–/– mice exhibited exacerbated ear swelling and increased numbers of IFN-γ+ CD8+ T cells in the skin. Adoptive T-cell transfer experiments revealed the involvement of the PD-1/PD-L1 pathway in the elicitation phase of contact hypersensitivity. Bone marrow chimera experiments showed that PD-L1 on radioresistant cells was responsible for this regulatory pathway. Flow cytometric analysis revealed that among the radioresistant cells in the skin, PD-L1 was most highly expressed on mast cells (MCs) before and after elicitation. Administration of anti–PD-L1 blocking antibody during the elicitation phase significantly enhanced ear swelling responses and increased the number of IFN-γ+CD8+ T cells in the skin of wild-type mice, whereas no significant effects were observed in MC-deficient (WBB6F1/J-KitW/KitW-v/J and C57BL/6-KitW-sh/W-sh) mice. The high level of expression of PD-L1 on human skin MCs was confirmed by database analysis and immunohistochemical analysis. Conclusion PD-L1 on MCs negatively regulates CD8+ T-cell activation in the skin.

Immunodeficient mice engrafted with human peripheral blood cells are promising tools for in vivo analysis of human patient individual immune responses. However, when human peripheral blood mononuclear cells (PBMCs) are transferred into NOG (NOD/Shi-scid, IL-2rg (null)) mice, severe graft versus host disease (GVHD) hinders long term detailed analysis. Administration of human PBMCs into newly developed murine MHC class I- and class II-deficient NOG (NOG-dKO; NOG- Iab, B2m-double-knockout) mice showed sufficient engraftment of human immune cells with little sign of GVHD. Immunization with influenza vaccine resulted in an increase in influenza-specific human IgG Ab, indicating induction of antigen-specific B cells in the NOG-dKO mice. Immunization with human dendritic cells pulsed with HLA-A2 restricted cytomegalovirus peptide induced specific cytotoxic T cells, indicating the induction of antigen-specific T cells in the NOG-dKO mice. Adoptive cell therapies (ACTs) using melanoma antigen recognized by T cells (MART-1)-specific TCR-transduced activated T cells showed strong tumor growth inhibition in NOG-dKO mice without any sign of GVHD accompanied by preferential expansion of the transferred MART-1-specific T cells. ACTs using cultured human melanoma infiltrating T cells also showed anti-tumor effects against autologous melanoma cells in NOG-dKO mice, in which changes in human cancer phenotypes by immune intervention, such as increased CD271 expression, could be evaluated. Therefore, NOG-dKO mice are useful tools for more detailed analysis of both the induction and effector phases of T-cell and B-cell responses for a longer period than regular NOG mice.

9542 Background: Anti-PD-1 antibody monotherapy (PD1) has been commonly used for patients with advanced acral melanoma (AM). However, recent studies have demonstrated the limited clinical efficacy of PD1 in AM compared to non-acral cutaneous melanoma, particularly in nail apparatus melanoma. Although advanced AM patients are strong candidates for first-line anti-PD-1 and anti-CTLA-4 combination therapy (PD1+CTLA4), data on the clinical efficacy of PD1+CTLA4 in AM are lacking. Thus, we aimed to compare the clinical efficacies of PD1+CTLA4 and PD1 in Japanese advanced AM patients. Methods: We retrospectively reviewed the clinical records of advanced AM patients treated with PD1+CTLA4 or PD1 as first-line immunotherapy at 23 Japanese institutions. Clinical response was assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Survival was estimated using Kaplan-Meier analysis. Toxicity was assessed according to CTCAE 4.0. Results: A total of 192 patients (median age, 72 years) with advanced AM (palm and sole melanoma, 135; nail apparatus melanoma, 57) were included in the study. PD1+CTLA4 and PD1 were used as first-line immunotherapy in 39 and 153 patients, respectively. The baseline demographics and characteristics were similar between the PD1+CTLA4 and PD1 groups, except for age (median age 67.3 vs. 73.2; P = 0.005). The objective response rate (ORR) in PD1+CTLA4 was significantly higher than that of the PD1 group (38.5% vs. 16.3%; P = 0.047). The median progression-free survival (PFS) and overall survival (OS) in the PD1+CTLA4 group tended to be longer than those of the PD1 group, but the differences were not significant (median PFS 7.3 months vs. 4.5 months; P = 0.19, median OS 43.6 months vs. 18.2 months; P = 0.19). In the subgroup analysis of the palm and sole melanoma cohorts, no significant differences in ORR, PFS, and OS were observed between the PD1+CTLA4 and PD1 groups (ORR 31% vs. 20.8%; P = 0.67, median PFS 5.3 months vs. 5.9 months; P = 0.87, median OS not reached vs. 22.3 months; P = 0.66). Meanwhile, the nail apparatus melanoma cohort in the PD1+CTLA4 group exhibited significantly higher ORR, and longer PFS and OS than the PD1 group (ORR 60% vs 6.1%; P < 0.001; median PFS 19.6 months vs 3.8 months; P = 0.008, median OS 43.6 months vs 13.5 months; P = 0.049). Due to immune-related adverse events in all cohorts, the treatment cessation rate was higher in the PD1+CTLA4 group than the PD1 group (59% vs. 11.8%). Conclusions: PD1+CTLA4 was clinically more efficacious than PD 1 in advanced AM patients. Notably, advanced nail apparatus melanoma patients were strong candidates for first-line PD1+CTLA4.

Recently, T-cell immunoreceptor with Ig and ITIM domains (TIGIT) was reported as a candidate for novel immune checkpoints. However, the impact of TIGIT on melanoma-specific cytotoxic T lymphocytes in the effector phase remains unclear. In this study, we demonstrated that melanoma cells control antimelanoma cytotoxic T lymphocyte responses via the TIGIT-CD155 interaction in the effector phase. TIGIT is an inhibitory receptor expressed on T cells, and CD155 is one of the cognate ligands expressed on the tumor cells or antigen-presenting cells. First, we confirmed that CD155 was constitutively expressed on melanoma cells. We then demonstrated that CD155 on melanoma cells suppressed cytokine release from melanoma-specific cytotoxic T lymphocytes via interaction with TIGIT. Overexpression of CD155 enhanced and its downregulation attenuated the suppressive effect. This suggested that antimelanoma cytotoxic T lymphocyte responses are controlled not only by an imbalance in CD226 (an activating molecule that binds to CD155) and TIGIT expression on T cells but also by the expression levels of CD155 on melanoma cells. In addition, the co-blockade of TIGIT and PD-1 signals synergistically elicited a response of tumor-infiltrating lymphocytes on autologous melanoma cells. These results suggest that the CD155-TIGIT interaction should be blocked for enhancement of antimelanoma immune responses.

Serine/threonine-protein kinase B-Raf (BRAF) inhibitors are very effective in treating melanoma with BRAF mutations. BRAF inhibitors suppress aberrant growth of melanoma cells caused by BRAF mutations. BRAF mutations reportedly result in melanoma cells releasing immunosuppressive factors, and BRAF inhibitors elicit anti-melanoma immune responses by reducing such factors. However, immunological characteristics of tumor cells that acquire resistance to BRAF inhibitors remain unknown. Here, we compared immunological characteristics between a melanoma cell line and its vemurafenib-resistant subline. No differences were observed in the status of BRAF mutations, expression of surface molecules related to antitumor T-cell responses or recognition by human leukocyte antigen-A*0201-matched melanoma-specific cytotoxic T lymphocytes in a short-term co-culture assay. However, resistant tumor cells released high amounts of interleukin-10 depending on aberrant activation of Akt signaling, and dendritic cell functions were considerably suppressed by culture supernatants of the resistant cells. Our findings demonstrated a novel immunological mechanism contributing to tumor growth owing to drug resistance to BRAF inhibitors.

Fournier's gangrene (FG) is an infrequent but highly lethal infection. Here we report a 74-year-old man who presented with genital swelling and severe malaise. Based on the physical and imaging examination results, the diagnosis of FG was confirmed. Intraoperative findings showed dirty necrosis of soft tissue, and a splinter-shaped foreign body was found in the perirectal region. The foreign body was thought to be the cause of the condition, and it was analyzed using Fourier transform infrared spectroscopy. We found that the foreign body was a mixture of calcium phosphate and protein, suggesting that the splinter was a bone. Moreover, during the medical interview, the patient mentioned about intake of fish around the time of onset of symptoms. Therefore, to confirm the results of the analysis, DNA was extracted from the foreign body, and genomic PCR with subsequent sequence analysis was performed. The DNA sequence was identical to that of Oncorhynchus kisutch, a salmon that is a very popular food in Japan. On the basis of these findings, we concluded that FG in this case was caused by the penetration into the rectum of an accidentally ingested fish bone. Although some cases of intra-abdominal abscess due to accidental ingestion of fish bone have been reported, FG caused by fish bone is extremely rare.

Background Canerpaturev (C–REV) is an oncolytic, spontaneous mutant of HSV-1, and is one of immunotherapies that can not only kill tumor cells but also modulate immune responses. We report the efficacy of Phase II multicenter trial of combination therapy using C-REV and ipilimumab (ipi) in melanoma patients (pts) who were refractory or intolerant to prior therapies. Methods Key entry criteria: age ≥ 20 yrs, ECOG PS 0-2, AJCC 7th Stage IIIB-IV unresectable melanoma, who received prior therapies and had measurable non-visceral lesion(s) suitable for C-REV injections. C-REV was injected into each tumor (1 x 107 TCID50/mL/dose, up to 5 mL); 4 injections q1wk; then up to 15 injections q3wks. Ipi (3 mg/kg) was administered 4 times, q3wks. Primary endpoint was Best Overall Response Rate (BORR) by immune-related response criteria (irRC). Results 28 pts were enrolled. Disease stage: 7.1% IIIB, 28.6% IIIC and 64.3% IV, and disease type: 39.3% acral lentiginous and 21.4% mucosal melanoma. Anti-PD-1 antibody was previously used in 89.3%. Severe adverse events (AEs, ≥G3) related to the study treatment was 35.7 %. Of 27 efficacy evaluable pts, BORR and disease control rate by irRC 11.1% and 55.6%, respectively. Pts with irPR and durable irSD longer than 24 wks were confirmed in 22.2 % (6 pts) and had no deaths (follow-up period: 298 - 446 days). The median OS was 318.0 days (95% C.I. 211.00 – not reached). Conclusions In melanoma, various immunotherapies and molecular targeted drugs have been approved for treatment options, but there are still unmet medical needs in particular in pts who failed in the 1st line therapy. In this trial, C-REV did not show the exacerbation in ipi toxicity and patients with irPR and durable irSD contributed to prolonging OS. Thus, C-REV plus ipi has potential to become a new treatment option for melanoma in ≥ 2nd-line setting. Clinical trial identification NCT03153085. Legal entity responsible for the study Takara Bio Inc. Funding Takara Bio Inc. Disclosure K. Yokota: Research grant / Funding (institution): Takara Bio Inc. T. Isei: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Bristol-Myers Squibb K.K.; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Ono Pharmaceutical Co., Ltd.; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Novartis Pharma K.K.; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: MSD K.K.; Honoraria (self): Mochida Pharmaceutical Co., Ltd.; Honoraria (self): Pfizer Japan Inc.; Honoraria (self), Travel / Accommodation / Expenses: Kaken Pharmaceutical Co.,Ltd.; Honoraria (self): Daiichi Sankyo Company, Limited.; Honoraria (self), Travel / Accommodation / Expenses: Maruho Co.,Ltd. ; Honoraria (self), Travel / Accommodation / Expenses: Kyowa Hakko Kirin Co., Ltd.; Honoraria (self): POLA-Pharma; Advisory / Consultancy: Merck Biopharma Co., Ltd; Research grant / Funding (institution): Takara Bio Inc.; Research grant / Funding (institution): Array BioPharma, Inc.; Research grant / Funding (institution): Amgen Inc. H. Uhara: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Ono Pharmaceutical Co., LTD; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: MSD K.K.; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd.; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Novartis Pharma K.K.; Honoraria (self), Research grant / Funding (institution): Maruho Co.,Ltd. ; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Bristol-Myers Squibb K.K.; Honoraria (self), Speaker Bureau / Expert testimony, Research grant / Funding (institution): POLA-Pharma; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Kyowa Hakko Kirin Co., Ltd.; Speaker Bureau / Expert testimony: Janssen Pharmaceutical K.K.; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Mitsubishi Tanabe Pharma Corporation; Research grant / Funding (institution): Taiho Pharmaceutical Co., Ltd.; Research grant / Funding (institution): Eisai Co., Ltd. ; Research grant / Funding (institution): AbbVie GK.; Research grant / Funding (institution): Maruho Co.,Ltd. ; Research grant / Funding (institution): Daiichi Sankyo Company, Limited. ; Research grant / Funding (institution): Tsumura & Co.; Research grant / Funding (institution): Mochida Pharmaceutical Co., Ltd.; Research grant / Funding (institution): Nippon Kayaku Co.,Ltd.; Research grant / Funding (institution): Torii Pharmaceutical Co.,Ltd; Research grant / Funding (institution): Kaken Pharmaceutical Co.,Ltd. Y. Fujisawa: Advisory / Consultancy: Eli Lilly Japan K.K. ; Advisory / Consultancy: Novartis Pharma K.K.; Research grant / Funding (institution): Ono Pharmaceutical Co., LTD; Research grant / Funding (institution): Bristol-Myers Squibb K.K.; Research grant / Funding (institution): Eisai Co., Ltd. ; Research grant / Funding (institution): Takara Bio Inc. T. Takenouchi: Speaker Bureau / Expert testimony: Ono Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: MSD K.K.; Speaker Bureau / Expert testimony: Novartis Pharma K.K.; Speaker Bureau / Expert testimony: Chugai Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: Bristol-Myers Squibb K.K.; Research grant / Funding (institution): Takara Bio Inc. Y. Kiyohara: Honoraria (self), Research grant / Funding (institution), Travel / Accommodation / Expenses: Ono Pharmaceutical Co., Ltd.; Honoraria (self), Research grant / Funding (institution): MSD K.K.; Honoraria (self), Research grant / Funding (institution): Bristol-Myers Squibb K.K.; Honoraria (self): Novartis Pharma K.K.; Honoraria (self): Chugai Pharmaceutical Co., Ltd.; Honoraria (self): Toray Industries, Inc.; Honoraria (self), Research grant / Funding (institution): Merck Biopharma Co., Ltd; Honoraria (self): Boehringer Ingelheim Japan, Inc.; Research grant / Funding (institution): Takara Bio Inc.; Honoraria (self), Research grant / Funding (institution): Amgen Inc. H. Uchi: Research grant / Funding (institution): Takara Bio Inc. H. Saruta: Speaker Bureau / Expert testimony: Ono Pharmaceutical Co., Ltd.; Speaker Bureau / Expert testimony: Kyowa Hakko Kirin Co., Ltd.; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Minophagen Pharmaceutical Co., LTD.; Research grant / Funding (institution): MSD K.K.; Research grant / Funding (institution): Takara Bio Inc. H. Ihn: Research grant / Funding (institution): Takara Bio Inc. T. Inozume: Research grant / Funding (institution): Takara Bio Inc. D. Watanabe: Advisory / Consultancy: Japan vaccine; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Maruho Co.,Ltd. ; Research grant / Funding (institution): Sanofi K.K.; Research grant / Funding (institution): Nippon Zoki Pharmaceutical Co., Ltd. ; Research grant / Funding (institution): Daiichi Sankyo Company, Limited.; Research grant / Funding (institution): Takara Bio Inc. A. Takahashi: Honoraria (self), Research grant / Funding (institution): Ono Pharmaceutical Co., Ltd; Honoraria (self), Research grant / Funding (institution): Bristol-Myers Squibb K.K.; Honoraria (self), Research grant / Funding (institution): Novartis Pharma K.K.; Research grant / Funding (institution): Takara Bio Inc. S. Fukushima: Research grant / Funding (institution): Takara Bio Inc. M. Tanaka: Full / Part-time employment: Takara Bio Inc. N. Yamazaki: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Ono Pharmaceutical Co., Ltd; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb K.K.; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): MSD K.K.; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Novartis Pharma K.K.; Research grant / Funding (institution): Takara Bio Inc.

2610 Background: C-REV, an oncolytic, spontaneous mutant of Herpes Simplex Virus type 1 (HSV-1), is a cancer immunotherapy agent that combine direct tumor cell killing with immune modulation. A phase I study for solid tumors with cutaneous and/or superficial lesions treated with C-REV monotherapy and a phase II study for unresectable or metastatic melanoma treated with C-REV and Ipi combination therapy were conducted. Immune status of cancer pts before and after administration of C-REV with/without Ipi has been unclear. Methods: A phase I study (n = 6) included solid tumor pts with cutaneous and/or superficial lesions treated with C-REV monotherapy (1 x 106 and 1 x 107 TCID50/mL/dose; 4 injections q2-4wk). In phase II study (n = 28), C-REV (1 x 107 TCID50/mL/dose; 4 injections q1wk; then up to 15 injections q3wk) was injected into each tumor for advanced melanoma pts. Four Ipi infusions (3 mg/kg) were administered at q3wk. Immune-monitoring was conducted before and after treatment in tumor microenvironment usingpaired biopsy samples by multiplex immunohistochemistry (mIHC) and in peripheral blood by flow cytometry (FCM). Results: In the phase I study, significant infiltrations of CD8+and CD4+ T cells were observed at tumor local site statistically in three pts (60%) among five pts. In the phase II study, FCM of peripheral blood (n = 10) showed that the responders (irSD, n = 7, 70%) tend to express the higher levels of ICOS on CD4+ T cells as a pharmacodynamic biomarker of ipi monotherapy reported previously (Ng Tang D, et al. Cancer Immunol Res. 2013) and lower levels of PD-L1 on monocyte after two months of treatment. Moreover, mIHC analysis of paired tumor biopsy samples (n = 11) revealed that five pts (45%) among 11 pts were confirmed persistent infection of C-REV at the injected site by qPCR. Disease control rate of pts with the virus DNA detected on Days 85/169 was higher than that without it (100% [n = 5, irPR; 1, irSD; 4] vs. 33% [n = 6, irSD; 2, irPD; 4]). Furthermore, median OS of pts with or without the DNA detected was 342 or 251 days respectively. Conclusions: Our results suggest C-REV injection in the tumor local site have potential to enhance systemic immune response of Ipi. Clinical trial information: NCT03153085.

Immune checkpoint therapy, which targets regulatory pathways in T cells to enhance antitumor immune responses, has led to important clinical advances. CD155 is expressed in various types of cancer, and this surface molecule on tumor cells functions either as a co-stimulatory molecule or a co-inhibitory molecule, depending on its receptor. CD226, a CD155 ligand, is mainly expressed on natural killer cells and CD8+ T cells, playing important roles in natural killer cell-mediated cytotoxicity. In this study, we investigated the expression and function of CD155 and CD226 in cutaneous T-cell lymphoma (CTCL). CD155 was strongly expressed on tumor cells and CD155 mRNA expression levels were increased in CTCL lesional skin. CD226 expression on natural killer cells and CD8+ cells in peripheral blood of CTCL patients was decreased. On the other hand, serum CD226 levels were significantly elevated in CTCL patients, strongly reflecting disease activity, suggesting that soluble CD226 in sera was generated by shedding of its membrane form. Recombinant CD226 itself showed cytotoxic activity against CD155-expressing CTCL cells in vitro. These data suggest that soluble CD226 elevated in sera of CTCL patients would be important for tumor immunity by interacting with CD155 on tumor cells.

Protein-transduction domains (PTDs) are short stretches of cationic amino acids that enable peptides, proteins, oligonucleotides, and other reagents to efficiently enter multiple cell types. Therefore, PTDs offer unique therapeutic opportunities for the treatment of many diseases. Previous studies examined the in vivo distribution of PTD-containing fusion proteins following administration via different routes, including portal vein, intravenous, intraperitoneal, and oral administration. Skin may be an appropriate target organ for this new molecular-carrier system; however, there are no studies on the in vivo kinetics and biological effects of PTD-containing proteins following intradermal application. Among the PTDs, poly-arginine peptides, especially nona-arginine (R9), is transported most efficiently with minimal cytotoxicity. Here, we review protein transduction technology from a different angle, as a novel tool in immunotherapeutic approaches to the skin cancers that depend on the biological characteristics of poly-arginine. This could be used in place of gene therapy for skin cancer patients.

There is no effective treatment for advanced extramammary Paget's disease (EMPD). The human epidermal growth factor receptor 2 (HER2) protein is often overexpressed in EMPD. Trastuzumab is a humanized monoclonal antibody against HER2 used in the treatment of breast cancers in which HER2 is overexpressed. We report a case of advanced EMPD in which trastuzumab and paclitaxel combination therapy was effective. The patient was a 70-year-old Japanese woman who presented with EMPD on the vulva and multiple metastatic lymph nodes. Immunohistochemical staining revealed strong HER2 protein expression in the primary tumor and metastatic lymph nodes. The patient received trastuzumab and paclitaxel. After 4 courses of this regimen, the mass on the vulva and the metastatic lymph nodes regressed. Our findings may imply that trastuzumab plus paclitaxel combination therapy is useful for the treatment of advanced EMPD overexpressing HER2.

CD8+ tumor-infiltrating lymphocytes (TILs) in human melanomas express high levels of PD-1 and are functionally impaired. However, adoptive cell therapy using in vitro-expanded TIL can be a highly effective therapy for patients with advanced melanoma. This discrepancy led us to further analyze the CD8+PD-1+ TILs. We found that the percentage of PD-1-expressing CD8+ T cells was higher in the tumor digests that generate tumor-reactive TILs after in vitro culture in interleukin-2 (P=0.0007). Also sorted and expanded CD8+PD-1+ T cells in tumor digests showed much higher tumor-specific interferon-γ production compared with CD8+PD-1⁻ T cells. These results suggested that tumor-specific CD8+ T cells in melanoma tumor digests are largely PD-1, and this population can recover function after culturing in interleukin-2. PD-1 has been reported as an inhibitory receptor on T cells. We found that the in vitro functional suppression of cultured-TILs from native levels of PD-L1 expression on melanomas was minimal, and moreover expression level of PD-1 on CD8+ tumor-specific TILs decreased during the culture. As a consequence, the PD-1 receptor can be a useful biomarker for enriching tumor-specific T cells from fresh melanomas.

Background We previously have shown that nona-arginine protein transduction domain (R9-PTD) induced efficient protein-antigen (Ag) transduction of dendritic cells (DCs) in vitro, resulting in the efficient induction of strong Ag-specific immune responses mediated by CD8+ and CD4+ T cells and in superior antitumour effects in vivo in cancer-bearing mice. Objectives The Ag-specific immune responses caused by intradermal (i.d.) injections of R9-PTD-containing protein Ags without DC preparation were investigated. We also investigated the antitumour effects by intratumoral (i.t.) injections of rR9-containing protein Ags. Methods Synthesized SIINFEKL peptide, or recombinant ovalbumin fusion proteins (rOVA, rR9-OVA), were directly injected into abdominal skin in naive C57BL/6 mice. OVA-specific cytotoxic T lymphocyte (CTL) activity, serum IgG titre and cytokine profiles were investigated. Histopathological analyses were also performed. In a cancer vaccination model, EG.7 (OVA-cDNA transfectants thymoma) cells were inoculated intradermally in C57BL/6 mice, and the antitumour effects were evaluated by i.t. injections of rR9-OVA in a treatment setting. Results i.d. injections of rR9-OVA into naive C57BL/6 mice elicited OVA-specific CTLs and produced IgG2-dominant immunoglobulin. The i.d. injections of rR9-OVA also induced inflammatory cell infiltrates containing neutrophils, monocytes and lymphocytes, as well as production of inflammatory cytokines such as interferon (IFN)-gamma, interleukin-2 and IFN-inducible protein 10, with presenting SIINFEKL epitopes on major histocompatibility complex (MHC) class I molecules at the injection area. i.t. injections of rR9-OVA into EG.7 tumour mass significantly suppressed tumour growth, and these effects were completely abrogated by the depletion of CD8+ T cells. These antitumour effects were superior to those elicited by i.t. injections of rR9-OVA-treated DCs. Conclusions i.d. injections of rR9-containing immunogenic Ag without adjuvants simultaneously induce dual immunological effects: the induction of Tc1- and Th1-dominant immune responses, and the induction of inflammatory and CTL-mediated immune responses at the injection area by expressing Ag epitopes on MHC class I molecules as targets. This simple vaccination approach with R9-PTD-containing fusion proteins might be useful as prophylactic immunotherapy for cancer or infectious diseases.

T(H)17 is a newly identified pathogenic memory CD4(+) T-cell lineage with potent agonist effects in some murine experimental autoimmunity models, however, its role in tumor immunology is still unclear. Clinical experience with interleukin (IL)-2 and ipilumumab [anti-cytotoxic T-lymphocyte antigen 4 (CTLA4) antibody], particularly in treating immunogenic malignancies such as melanoma and renal cell carcinoma (RCC), has suggested an association between a variety of autoimmune phenomena and tumor regression. To investigate this issue in patients with RCC, we isolated T-cell clones from peripheral blood that released IL-17 on stimulation with their autologous RCC tumor line. Clones were generated from 1 patient before any systemic treatment by in vitro stimulation with dendritic cells, autologous tumor, and IL-2 in the presence of anti-CTLA4 antibody. That patient subsequently received treatment with ipilimumab and showed both objective tumor regression and immune-mediated colitis. Limiting dilution cloning of his tumordendritic cell-stimulated T cells produced the 3G8D CD4(+) clone, which secreted both IL-17 and interferon-g when cocultured with the autologous RCC line (transduced with class II transactivation molecule to induce major histocompatibility complex-class II expression). Broader analysis of its cytokine secretion profile showed large amounts of IL-8 when cocultured with RCC, but not when triggered with phorbol 12-myristate 13-acetate and ionomycin. This led to the discovery that IL-8 was being produced by the RCC cells in response to T-cell–derived IL-17. This effect of exogenous IL-17 on IL-8 release from tumor was seen in 5 of 8 RCCs, but not in other tumors tested. Preliminary data on the frequency of IL-17–secreting T cells in the lymphocytes infiltrating RCCs suggest that there may be a positive correlation between this frequency and IL-8 production by nonlymphoid cells as determined by quantitative reverse transcription-polymerase chain reaction. This report extends the known bidirectional interactions between immune cells and malignant cells in the tumor microenvironment that can shape and modulate the host immune response to cancer.

We previously reported early evidence of the human Fc receptor-like A (hFCRLA), an antigen (Ag) that was specifically expressed in melanocytes, melanoma cells, and some B-cell states, and was recognized by IgG antibodies from melanoma patients. Recently, it has been demonstrated that hFCRLA is expressed in most human B-cell lymphoma tissues. In this report, we investigated the potential of FCRLA as a tumor-associated Ag of B-cell lymphoma for immunotherapy. We confirmed that murine FCRLA (mFCRLA) was expressed and distributed in murine tissues similar to hFCRLA. Recombinant mFCRLA fusion protein was constructed with a polyarginine (R9)-protein-transduction domain (PTD) (rR9-HA-mFCRL), and was transduced into bone marrow-derived dendritic cells (DC) ex vivo. Mice immunized with rR9-HA-mFCRL-treated DC primed cytotoxic T-lymphocyte (CTL) that killed the B-cell lymphoma cell line (A20), which express mFCRLA abundantly. In a tumor challenging study, A20 tumor growth inoculated in skin was significantly suppressed in mice vaccinated with rR9-HA-mFCRL-treated DC, compared with control mice. These results indicated that FCRLA is a potential target Ag in immunotherapy for B-cell lymphoma. In addition, our experimental system using R9-PTD-containing full-length proteins might be a useful method to analyze the immunogenicity of novel candidates of tumor-associated Ags in vivo.

ジアミド誘導体を配合した入浴剤のアトピー性皮膚炎患者に対する有用性を検討するために，合成擬似セラミドなどの油性保湿成分とユーカリエキスおよびオーツ麦エキスを配合した入浴剤を対照処方とし，この対照入浴剤処方にジアミド誘導体を配合した入浴剤処方を用いて二重盲検法による入浴での使用試験を行った。対象はアトピー性皮膚炎患者21例(ジアミド誘導体配合入浴剤使用群13例，対照入浴剤使用群8例)で，入浴剤を3～6週間使用させ，身体部位の乾燥症状や痒みに対する効果を検討した。その結果，1．対照入浴剤使用群では「乾燥」および「落屑」において有意な改善効果が認められたのに対し，ジアミド誘導体配合入浴剤使用群では「乾燥」，「落屑」に加え，「そう痒・そう破痕」および「角層水分量」において有意な改善効果が認められた。2．特に高頻度(毎週4回以上)の使用患者では，ジアミド誘導体配合入浴剤使用群(7例)において「入浴中のかゆみスコア」の改善傾向と「入浴後のかゆみスコア」の有意な改善が認められたのに対し，対照入浴剤使用群(7例)においてはいずれも有意な改善を認めなかった。また，「入浴後のかゆみスコア」の改善を示す症例数は，ジアミド誘導体配合入浴剤使用群の方が対照入浴剤使用群と比較し，有意に多かった。以上の結果より，ジアミド誘導体を配合した入浴剤の使用は，アトピー性皮膚炎の治療において一つの有用な補助療法となる可能性が示唆された。

我々は, 進行期メラノーマを合併した人工透析患者にDAC-Tam療法を施行したので報告する。key drugであるシスプラチンの投与量は, 他の癌の透析患者に対して投与された過去の報告に基づいて50mg/m2とし, 投与24時間後に透析を行った。抗腫瘍効果や副作用の発現に関連する血清中の非蛋白結合platinum (free Pt) 濃度を経時的に測定し, 透析患者に特有の血中動態をとること, 効果を期待するに十分な血中濃度に達していたこと, 血中濃度は透析によりコントロールできることを確認した。一時的な血球減少以外に副作用は認めず, 1ヵ月後のCTでは腫瘍の増大が停止しているのを確認できた。今後, 人工透析を行っている悪性腫瘍患者数の増加が予想される中で, 薬剤の血中動態を考慮し適正なモニタリングのもとに行う化学療法はこうした患者への治療の選択肢を広げることができる可能性がある。

Background Woolly hair is a hereditary disorder characterized by fine and tightly curled hair. Autosomal recessive woolly hair (ARWH) was recently determined to result from mutations in either the lipase H (LIPH) or the LPAR6 (P2RY5) gene. Case report An 8-year-old boy (proband) and his 11-year-old brother presented with tightly coiled and sparse scalp hair. The boys did not have cardiomyopathy, palmoplantar keratoderma, or facial dysmorphism. Their parents had normal hair growth and no woolly hair. The sequence analysis of their genomic DNA revealed that the proband and his brother had a homozygous mutation of c.736T > A in the LIPH gene. On the basis of these findings, these patients were diagnosed with ARWH. Conclusions To the best of our knowledge, only 20 cases of ARWH have been previously reported in Japan. However, several reports showed that one mutation was detected in the 4/200 normal and unrelated alleles in healthy Japanese control individuals, indicating the presence of ARWH in patients with extremely mild symptoms.

We report a case of an 88-year-old woman with a decalvant, erythematous, ulcerated tumor extending from the right temporal to occipital region. Histopathological analysis revealed a dense infiltration of medium-to-large-sized atypical cells throughout the entire dermis. The result of immunohistochemical analysis showed that the infiltrating T cells expressed programmed death-1 (PD-1), Bcl-6 and CXCL13. Flow cytometry analysis showed that CD4(+) PD-1(hi) T cells also expressed CD10, inducible T-cell co-stimulator and CXCR5. On the basis of the clinical appearance and the histopathological findings, we diagnosed the patient with primary cutaneous peripheral T-cell lymphoma, not otherwise specified. Recently, the concept of primary cutaneous follicular helper T (TFH)-cell lymphoma was proposed, and in this case, tumor cells clearly expressed TFH-cell markers. Therefore, we considered this case to be a variant of the entity. Although this entity is still provisional, this case supports the new concept.

T cell responses specific for melanoma cells and melanocytes appear to be involved in the rejection of melanoma tumors, as well as in the development of autoimmune reactions in patients with Vogt-Koyanagi-Harada disease (VKH), sympathetic ophthalmia, or autoimmune vitiligo. Some of the target antigens for those T cells have been isolated using cDNA expression cloning with melanoma reactive T cells derived from lymphocytes tumor infiltrating (TIL) of patients with melanoma. These include melanocyte specific proteins, such as tyrosinase, TRP1, TRP2, gp100, and MART-1, cancer-testis antigens, and mutated peptides derived from genetic alterations in melanoma cells. Some of the melanoma reactive T cells appear to respond to cryptic or subdominant self epitopes in melanosomal proteins. Modification of those epitopes to increase their immunogenicity by replacement of amino acids at primary anchor residues for peptide/MHC binding, allowed an improvement in immunotherapy for patients with melanoma. Targets for autoreactive T cells against melanocytes in those autoimmune disorders remain to be identified. Isolation of novel target antigens is important for understanding these pathological T cell responses, as well as for developing new diagnostic and treatment methods for these diseases. A variety of techniques, including cDNA expression cloning with T cells, serological analysis of recombinant cDNA expression libraries (SEREX), cDNA subtraction with representational differential analysis (RDA), and serial analysis of gene expression (SAGE) are now being applied to identify novel melanoma/melanocyte antigens recognized by T cells and antibodies.

IFN-γ released from cytotoxic T lymphocytes (CTLs) during the effector phase is essential for rejecting bulky melanoma tumors. In contrast, IFN-γ is known to induce certain immunosuppressive factors in tumor cells such as programmed cell death 1 ligand 1 (PD-L1). In this study, we have identified candidates for IFN-γ-inducible CTL-suppressive factors in melanoma cells using complementary DNA microarray analysis, and CD271/p75/neurotrophin receptor (NTR) was one of the candidate genes. Recently, CD271 was identified as a marker of the cancer stem cell–like population in human melanoma tissues. In this study, we showed that overexpression of CD271 on melanoma cells suppressed the in vitro activation of melanoma-specific CTLs. This suppression was mediated by CD271 ligation with activated CTL-derived nerve growth factor and the subsequent downregulation of melanoma antigens. Moreover, we found that the expression levels of PD-L1 on melanoma cells correlated with those of CD271, and they additively suppressed the activation of melanoma-specific CTLs. To the best of our knowledge, the role of overexpression of CD271 in an anti-melanoma T-cell response has been unreported.

Many recent clinical trials of immunotherapy for advanced tumors have reported remarkable results. For example, blockade of cytotoxic T-lymphocyte antigen 4 (CTLA-4) significantly improved median overall survival of melanoma patients. Blockade of programmed cell death 1 (PD-1) or programmed cell death 1 ligand 1 (PD-L1) induced durable tumor regression and prolonged disease stabilization in patients with advanced cancers, including melanoma, non-small-cell lung cancer, and renal cell cancer. In addition, adoptive cell transfer of tumor infiltrating lymphocytes (TILs) and T cells transduced with high avidity T cell receptor (TCR) genes have been reported to elicit marked durable tumor regression in melanoma patients. Further, clinical trials of cancer vaccines targeting various tumors have been conducted to prolong overall survival. In this review, some remarkable results achieved in recent clinical trials are summarized.