Characterization of the Immunological Status of Hypermutated Solid Tumors in the Cancer Genome Analysis Project HOPE

BACKGROUND

Many reports demonstrate that a high tumor mutation burden (TMB-H) is closely associated with good prognosis of cancer. However, specific studies investigating the association of various TMB statuses with overall survival in patients with solid tumors are scarce.

PATIENTS AND METHODS

In the present study, we investigated the association of TMB status with overall survival in 5,072 patients with cancer from the HOPE project and clarified the specific mechanism responsible for the good prognosis of the TMB-H group. All tumors were classified into one of four groups based on TMB: ultralow (UL), low (L), intermediate (I) and high (H).

RESULTS

The TMB-H group had a better prognosis than the TMB-I and TMB-L groups, but not than the TMB-UL group. Analyzing the expression of 293 immune response-associated genes, 17 genes were up-regulated in the TMB-H group compared to the TMB-I and TNB-L groups, and two genes [CD274 and interferon-γ (IFNG)] were identified as good prognostic factors. Analysis of immune cell populations inside tumors demonstrated that the frequencies of exhausted CD8⁺ T-cells, activated effector CD8⁺ T-cells and natural killer cells were significantly higher in the TMB-H group. The T-cell receptor repertoire numbers and the diversity evenness score (DE50) were lower in the TMB-H group than in TMB-UL group; however, no association of the DE50 value with the binding or elution affinity of epitope peptides from neoantigens was found.

CONCLUSION

One possible mechanism for the good prognosis of the TMB-UL group compared to the TMB-H group might be that the TMB-UL group features a balance between immunosuppression and immunostimulation.

Development of an Automatic Measurement Method for CD8 and PD-1 Positive T Cells Using Image Analysis Software

BACKGROUND/AIM

With the progress in cancer immunotherapy using immune checkpoint blockade (ICB) therapy, histological observations of tumor-infiltrating lymphocyte (TIL) status are needed to evaluate the antitumor effect of ICB using imaging analysis software.

MATERIALS AND METHODS

Formalin-fixed paraffin-embedded sections obtained from colorectal cancer and gastric cancer patients with more than 500 single nucleotide variants were stained with anti-CD8 and anti-PD-1 antibodies. Based on our own algorithm and imaging analysis software, an automatic TIL measurement method was established and compared to the manual counting methods.

RESULTS

In the CD8⁺ T cell number measurement, there was a good correlation (r=0.738 by Pearson test) between the manual and automated counting methods. However, in the PD-1⁺ T cell measurement, there was a large difference in TIL numbers in both groups. After adjustment of the parameter settings, the correlation between the manual and automated methods in the PD-1⁺ T cell measurements improved (r=0.668 by Pearson test).

CONCLUSION

An imaging software-based automatic measurement could be a simple and useful tool for evaluating the therapeutic effect of cancer immunotherapies in terms of TIL status.

Identification of tumor microenvironment-associated immunological genes as potent prognostic markers in the cancer genome analysis project HOPE

Project High-tech Omics-based Patient Evaluation (HOPE), which used whole-exome sequencing and gene expression profiling, was launched in 2014. A total of ~2,000 patients were enrolled until March 2016, and the survival time was observed up to July 2019. In our previous study, a tumor microenvironment immune type classification based on the expression levels of the programmed death-ligand 1 (PD-L1) and CD8B genes was performed based on four types: A, adaptive immune resistance; B, intrinsic induction; C, immunological ignorance; and D, tolerance. Type A (PD-L1⁺ and CD8B⁺) exhibited upregulated features of T helper 1 antitumor responses. In the present study, survival time analysis at 5 years revealed that patients in type A had a better prognosis than those in other categories [5 year survival rate (%); A (80.5) vs. B (73.9), C (73.4) and D (72.6), P=0.0005]. Based on the expression data of 293 immune response-associated genes, 62 specific genes were upregulated in the type A group. Among these genes, 18 specific genes, such as activated effector T-cell markers (CD8/CD40LG/GZMB), effector memory T-cell markers (PD-1/CD27/ICOS), chemokine markers (CXCL9/CXCL10) and activated dendritic cell markers (CD80/CD274/SLAMF1), were significantly associated with a good prognosis using overall survival time analysis. Finally, multivariate Cox proportional hazard regression analyses of overall survival demonstrated that four genes (GZMB, HAVCR2, CXCL9 and CD40LG) were independent prognostic markers, and GZMB, CXCL9 and CD40LG may contribute to the survival benefit of patients in the immune type A group.

Alternative Evaluation of an ELISPOT Assay Using Cytokine Activity as a Novel Parameter

BACKGROUND/AIM

The enzyme-linked immunospot (ELISPOT) assay is a well-established method used to evaluate the strength of T cell-mediated immune activity, and accepted as a standard functional immunological assay. Cytokine activity is a novel parameter reflecting spot size and intensity, which has not been used in ELISPOT assay before.

MATERIALS AND METHODS

In the present study, from 113 ELISPOT assay data derived from previous clinical trials with dendritic cell vaccines, both spot number count and cytokine activity data for IFN-γ secretion were obtained using an ELISPOT reader. Comparing the new parameter cytokine activity with the existing parameter spot number, the feasibility of cytokine activity was investigated.

RESULTS

There were no significant differences in sensitivity and specificity between spot number and cytokine activity among ELISPOT assay data from CMVpp65 and other antigen peptide-stimulated cytotoxic T lymphocytes.

CONCLUSION

Although cytokine activity is a novel parameter unreported so far, it did not show any advantages in the evaluation T cell immune responses compared to the existing spot number parameter.

Alpha-type-1 Polarized Dendritic Cell-based Vaccination in Newly Diagnosed High-grade Glioma: A Phase II Clinical Trial

BACKGROUND/AIM

Glioblastoma multiforme (GBM) is an intractable tumor that has a very poor prognosis despite intensive treatment with temozolomide plus radiotherapy.

PATIENTS AND METHODS

Sixteen newly diagnosed patients with high-grade gliomas were enrolled in a phase II study of the α-type-1 DC vaccine. Briefly, DCs obtained from the culture of enriched monocytes in the presence of a cytokine cocktail, were pulsed with a cocktail of 5 synthetic peptides and cryopreserved until injection into patients.

RESULTS

The amount of IL-12 produced by activated DCs was higher than that previously reported. Among 15 evaluable patients, 10 showed positive CTL responses to any peptides in an ELISPOT assay. After 6 years of observation, five patients were still alive, and two of these patients were relapse-free. Moreover, a significant survival-prolonging effect was verified in DC-treated glioma patients.

CONCLUSION

Peptide-cocktail-pulsed α-type-1 DC vaccines have a potential therapeutic effect on survival when used in combination with the standard regimen, which is partly based on IL-12-IFN-γ-mediated T-cell activation.

Effect of preoperative chemoradiotherapy on the immunological status of rectal cancer patients

The aim of the study was to investigate the effect of chemo-radiation on the genetic and immunological status of rectal cancer patients who were treated with preoperative chemoradiotherapy (CRT). The expression of immune response-associated genes was compared between rectal cancer patients treated (n = 9) and not-treated (n = 10) with preoperative CRT using volcano plot analysis. Apoptosis and epithelial-to-mesenchymal transition (EMT) marker genes were analysed by quantitative PCR (qPCR). Other markers associated with the tumor microenvironment (TME), such as tumor-infiltrating lymphocytes (TIL) and immune checkpoint molecules, were investigated using immunohistochemistry (IHC). The clinical responses of preoperative CRT for 9 rectal cancer patients were all rated as stable disease, while the pathological tumor regression score (TRG) revealed 6 cases of grade2 and 3 cases of grade1. According to the genetic signature of colon cancers, treated tumors belonged to consensus molecular subtype (CMS)4, while not-treated tumors had signatures of CMS2 or 3. CRT-treated tumors showed significant upregulation of EMT-associated genes, such as CDH2, TGF-beta and FGF, and cancer stem cell-associated genes. Additionally, qPCR and IHC demonstrated a suppressive immunological status derived from the upregulation of inflammatory cytokines (IL-6, IL-10 and TGF-beta) and immune checkpoint genes (B7-H3 and B7-H5) and from M2-type macrophage accumulation in the tumor. The induction of EMT and immune-suppressive status in the tumor after strong CRT treatment urges the development of a novel combined therapy that restores immune-suppression and inhibits EMT, ultimately leading to distant metastasis control.

Antitumor activity of the PD-1/PD-L1 binding inhibitor BMS-202 in the humanized MHC-double knockout NOG mouse

Recently, the first series of small molecule inhibitors of PD-1/PD-L1 were reported by Bristol-Myers Squibb (BMS), which were developed using a homogeneous time-resolved fluorescence (HTRF)-based screening investigation of the PD-1/PD-L1 interaction. Additional crystallographic and biophysical studies showed that these compounds inhibited the interaction of PD-1/PD-L1 by inducing the dimerization of PD-L1, in which each dimer binds one molecule of the stabilizer at its interface. However, the immunological mechanism of the antitumor effect of these compounds remains to be elucidated. In the present study, we focused on BMS-202 (a representative of the BMS compounds) and investigated its antitumor activity using in vitro and in vivo experiments. BMS-202 inhibited the proliferation of strongly PD-L1-positive SCC-3 cells (IC₅₀ 15 μM) and anti-CD3 antibody-activated Jurkat cells (IC₅₀ 10 μM) in vitro. Additionally, BMS-202 had no regulatory effect on the PD-1 or PD-L1 expression level on the cell surface of these cells. In an in vivo study using humanized MHC-double knockout (dKO) NOG mice, BMS-202 showed a clear antitumor effect compared with the controls; however, a direct cytotoxic effect was revealed to be involved in the antitumor mechanism, as there was no lymphocyte accumulation in the tumor site. These results suggest that the antitumor effect of BMS-202 might be partly mediated by a direct off-target cytotoxic effect in addition to the immune response-based mechanism. Also, the humanized dKO NOG mouse model used in this study was shown to be a useful tool for the screening of small molecule inhibitors of PD-1/PD-L1 binding that can inhibit tumor growth via an immune-response-mediated mechanism.

Impact of combination therapy with anti-PD-1 blockade and a STAT3 inhibitor on the tumor-infiltrating lymphocyte status

Recently, clinical studies using anti-immune checkpoint molecule antibodies have been successful in solid tumors, such as melanoma and non-small cell lung cancers. However, pancreatic cancers are still intractable and difficult to treat once recurrence or metastasis occurs; thus, novel combined use of immune checkpoint blockade (ICB) with molecular targeted drugs is considered a therapeutic option. Previously, we developed a novel humanized MHC-double knockout (dKO) NOG mouse model and demonstrated that an anti-PD-1 antibody or a STAT3 inhibitor showed anti-tumor effects through an immunological mechanism. In the current study, using a humanized mouse model, we aimed to develop a combination therapy with an anti-PD-1 antibody and a STAT3 inhibitor (STX-0119) for use in vivo against pancreatic cancer. In an in vitro investigation, STX-0119 showed weak to moderate cytotoxic activity against several pancreatic cancer cell lines, which exhibited activated pSTAT3 and weak PD-L1 expression. However, unexpectedly, an in vivo study indicated that the combination of the anti-PD-1 antibody with STX-0119 remarkably reduced the anti-tumor effect and TIL numbers despite the effective anti-tumor activity against pancreatic cancer was produced individually by STX-0119 and the anti-PD-1 antibody. These results suggested that the combination of an anti-PD-1 antibody with specific signal inhibiting drugs should be carefully evaluated to avoid unexpected side effects, and such studies might contribute to the development of an effective combination regimen of ICB with cancer-targeting drugs such as tyrosine kinase inhibitors (TKIs).

A T-cell-engaging B7-H4/CD3-bispecific Fab-scFv Antibody Targets Human Breast Cancer

PURPOSE

The B7 homolog 4 (B7-H4, VTCN1) is an immune checkpoint molecule that negatively regulates immune responses and is known to be overexpressed in many human cancers. Previously, we generated a mouse anti-human B7-H4 mAb that did not have a significant antitumor effect in vivo probably because of molecule instability. In this study, we designed a B7-H4/CD3-bispecific antibody (BsAb) and investigated its antitumor activity in vitro and in vivo using a humanized mouse model.

EXPERIMENTAL DESIGN

cDNAs of the antibody-binding fragment (Fab)-single-chain variable fragment (scFv) and scFv-scFv of the anti-B7-H4/CD3 BsAb were synthesized, and the BsAb antibodies were produced in HEK293 cells. The antitumor activity against human breast cancer cells by human peripheral blood mononuclear cells (hPBMC) with BsAb was measured by lactate dehydrogenase release in vitro, and in vivo using hPBMC-transplanted MHC class I- and class II-deficient NOG mice.

RESULTS

hPBMCs with anti-B7-H4/CD3 BsAbs successfully lysed the human breast cancer cell line MDA-MB-468 (EC₅₀: 0.2 ng/mL) and other B7-H4⁺ cell lines in vitro. When BsAb was injected in a humanized mouse model, there was an immediate and strong antitumor activity against MDA-MB-468, HCC-1954, and HCC-1569 tumors and CD8⁺ and granzyme B⁺ CTL infiltration into the tumor, and there were no adverse effects after long-term observation. CD8⁺ T-cell depletion by an anti-CD8 antibody mostly reduced the antitumor effect of BsAb in vivo.

CONCLUSIONS

An anti-B7-H4/CD3 BsAb may be a good therapeutic tool for patients with B7-H4⁺ breast cancers.

Classification of tumor microenvironment immune types based on immune response-associated gene expression

In 2014, the Shizuoka Cancer Center launched project High‑tech Omics‑based Patient Evaluation (HOPE), which features whole exome sequencing (WES) and gene expression profiling (GEP) of fresh surgical specimens from cancer patients. With the development of clinical trials of programmed death‑1 (PD‑1)/PD‑ligand 1 (PD‑L1) blockade, PD‑L1 expression and a high tumor mutation burden become possible biomarkers that could be used to predict immune responses. In this study, based on WES and GEP data from 1,734 tumors from the HOPE project, we established a tumor microenvironment (TME) immune‑type classification consisting of 4 types to evaluate the immunological status of cancer patients and analyze immunological pathways specific for immune types. Project HOPE was conducted in accordance with the Ethical Guidelines for Human Genome and Genetic Analysis Research with the approval of the Institutional Review Board. Based on the expression level of the PD‑L1 and CD8B genes, the immunological status was divided into 4 types as follows: A, PD‑L1+CD8B+; B, PD‑L1+CD8B‑; C, PD‑L1‑CD8B‑; and D, PD‑L1‑CD8B+. Type A, with PD‑L1+ and CD8B+, exhibited an upregulation of cytotoxic T lymphocyte (CTL) killing‑associated genes, T‑cell activation genes, antigen‑presentation and dendritic cell (DC) maturation genes, and T‑cell‑attracting chemokine genes, which promoted Th1 antitumor responses. By contrast, type C, with PD‑L1‑ and CD8B‑, exhibited a low expression of T‑cell‑activating genes and an upregulation of cancer driver gene signaling, which suggested an immune‑suppressive status. With regard to hypermutator tumors, PD‑L1+ hypermutator cases exhibited a specific upregulation of the IL6 gene compared with the PD‑L1‑ cases. On the whole, our data indicate that the classification of the TME immune types may prove to be a useful tool for evaluating the immunological status and predicting antitumor responses and prognosis.

Immune response-associated gene profiling in Japanese melanoma patients using multi-omics analysis

Project High-tech Omics-based Patient Evaluation (HOPE), including comprehensive whole-exome sequencing (WES) and gene expression profiling (GEP) using freshly resected tumor specimens, has been in progress since its implementation in 2014. Among a total of 1,685 cancer patients, 13 melanoma patients were registered in the HOPE Project and were characterized using multi-omics analyses. Among the 13 melanoma patients, 4 were deceased, and 9 were alive. The mean overall survival (OS) and relapse‑free survival (RFS) times of the melanoma patients were 16.9 and 14.7 months, respectively. Previously, we developed an immune response‑associated gene list, which consisted of 164 genes in Project HOPE, for evaluating the immunological status. In the present study, the association of immune response‑associated gene expression with immunological parameters, such as programmed death-ligand 1 (PD-L1) and CD8 expression levels, single nucleotide variant (SNV) number, and Vogelstein driver gene mutation number, was investigated. With respect to PD-L1 expression, both immuno-suppression and immuno-stimulation-related genes were upregulated in PD-L1-positive melanomas. In contrast, regarding Vogelstein driver mutations, several T-cell activation-related genes were significantly downregulated in the high driver gene mutation group. In addition, many T-cell activation-related genes were upregulated in the CD8-positive melanomas. The correlation of immune response-associated gene expression with the survival time of the melanoma patients was investigated. Eight specific genes were commonly identified as genes that were significantly correlated for both the overall OS and RFS time, which could be possible prognostic factors for melanoma patients. These results revealed that an immune response-associated gene panel could be an informative tool for evaluating the immunological status prior to clinical immunotherapy in the upcoming era of genomic cancer medicine.

Melanoma patient response to nivolumab treatment for metastatic lung lesions: Multi-OMICS analysis in Project HOPE

A 70-year-old woman was diagnosed with a malignant melanoma of the occipital skin which was resected; however, multiple lung metastases were detected. Nivolumab therapy was initiated and partial response was obtained. However, the patient was diagnosed with grade 2 interstitial pneumonitis. Prednisolone administration was initiated and the interstitial pneumonitis shadow disappeared. However, then a right rib metastasis was noticed and given radiation therapy. After progressive disease was obtained, the metastatic lesion was resected, and no relapse occurred until skeletal muscle metastasis was found. According to whole-exome sequencing and gene expression profiling, the rib and skeletal muscle metastatic lesions showed an upregulated expression of programmed death-ligand 1 mRNA and a high single-nucleotide variant (SNV) number. The current melanoma case is representative of a patient who responded to nivolumab therapy, and showed typical immunological markers for responders such as high PD-L1 expression and high SNV.

Multi-omics Profiling of Patients with Melanoma Treated with Nivolumab in Project HOPE

BACKGROUND

Project HOPE (High-tech Omics-based Patient Evaluation) has been in progress since 2014 and uses whole-exome sequencing (WES) and gene expression profiling (GEP). Among a total of 1,685 patients with cancer, 13 with melanoma were registered and characterized using multi-omics analyses to investigate specific biomarkers in responders to programmed cell death-1 (PD-1) blockade.

MATERIALS AND METHODS

The patients with melanoma comprised of six males and seven females, and their mean age was 68 years. Five patients were treated with nivolumab, and two were responders.

RESULTS

GEP analysis demonstrated that PD-L1 expression was positive in for cases, and melanoma-associated antigens and tumor signaling-associated genes were up-regulated in tumor compared with normal tissues. Additionally, WES analysis indicated more single nucleotide variants (SNVs) per melanoma tumor compared to other tumor types. Remarkably, a case of complete remission after nivolumab therapy showed high expression of PD-L1 protein and the highest number of SNVs.

CONCLUSION

The novel approach used in Project HOPE might be an efficient tool that facilitates identifying specific biomarkers predictive of good responders to anti-PD-1 therapy.

Immune response-associated gene analysis of 1,000 cancer patients using whole-exome sequencing and gene expression profiling-Project HOPE

Project HOPE (High-tech Omics-based Patient Evaluation) has been progressing since its implementation in 2014 using whole-exome sequencing (WES) and gene expression profiling (GEP). With the aim of evaluating immune status in cancer patients, a gene panel consisting of 164 immune response-associated genes (56 antigen-presenting cell and T-cell-associated genes, 34 cytokine- and metabolism-associated genes, 47 TNF and TNF receptor superfamily genes, and 27 regulatory T-cell-associated genes) was established, and its expression and mutation status were investigated using 1,000 cancer patient-derived tumors. Regarding WES, sequencing and variant calling were performed using the Ion Proton system. The average number of single-nucleotide variants (SNVs) detected per sample was 183 ± 507, and the number of hypermutators with more than 500 total SNVs was 51 cases. Regarding GEP, seven immune response-associated genes (VTCN1, IL2RA, ULBP2, TREM1, MSR1, TNFSF9 and TNFRSF12A) were more than 2-fold overexpressed compared with normal tissues in more than 2 organs. Specifically, the positive rate of PD-L1 expression in all patients was 25.8%, and PD-L1 expression was significantly upregulated in hypermutators. The simultaneous analyses of WES and GEP based on immune response-associated genes are very intriguing tools to screen cancer patients suitable for immune checkpoint antibody therapy.

Combination of a STAT3 Inhibitor and an mTOR Inhibitor Against a Temozolomide-resistant Glioblastoma Cell Line

BACKGROUND

Temozolomide-resistant (TMZ-R) glioblastoma is very difficult to treat, and a novel approach to overcome resistance is needed.

MATERIALS AND METHODS

The efficacy of a combination treatment of STAT3 inhibitor, STX-0119, with rapamycin was investigated against our established TMZ-resistant U87 cell line.

RESULTS

The growth-inhibitory effect of the combination treatment was significant against the TMZ-R U87 cell line (IC₅₀: 78 μM for STX-0119, 30.5 μM for rapamycin and 11.3 μM for combination of the two). Western blotting analysis demonstrated that the inhibitory effect of STX-0119 on S6 and 4E-BP1 activation through regulation of YKL-40 expression occurred in addition to the inhibitory effect of rapamycin against the mTOR pathway.

CONCLUSION

These results suggest that the STAT3 pathway is associated with the mTOR downstream pathway mediated by YKL-40 protein, and the combination therapy of the STAT3 inhibitor and rapamycin could be worth developing as a novel therapeutic approach against TMZ-resistant relapsed gliomas.

Unstable B7-H4 cell surface expression and T-cell redirection as a means of cancer therapy

Tumor immune regulation has been demonstrated in clinical studies using antibodies targeted to the B7/CD28 family. B7 homolog 4 (B7-H4) negatively regulates immune responses and is overexpressed in many types of human cancer, indicating that B7-H4 may be a potential target of cancer therapy. B7-H4 expression is affected by the microenvironment, and its presence has been reported in cancer tissues and immune cells. We found an upregulation of B7-H4 expression using comprehensive whole exome sequencing and gene expression profiling (project HOPE) launched by the Shizuoka Cancer Center based on tumor tissue samples from 1,058 cancer patients. We were successful in producing monoclonal antibodies for B7-H4 and demonstrated B7-H4 dimerization and rapid cell surface disappearance by antibody cross-linking in breast cancer cells, even under typical conditions. These observations may explain why antibody-dependent cellular cytotoxicity (ADCC) did not function in vivo on the B7-H4-expressing tumor cells. Unstable cell surface antigens are not suitable as targets for ADCC, and we therefore performed an indirect ADCC-redirecting T-cell cytotoxicity assay to study B7-H4 using polyclonal anti-mouse IgG antibody-mediated linking. Our results showed the possibility of targeting the B7-H4 molecule as a means of treating cancer.

Antitumor Effect of Programmed Death-1 (PD-1) Blockade in Humanized the NOG-MHC Double Knockout Mouse

PURPOSE

Humanized mouse models using NOD/Shi-scid-IL2rγ^null (NOG) and NOD/LtSz-scid IL2rγ^null (NSG) mouse are associated with several limitations, such as long incubation time for stem cell engraftment and the development of xenograft versus host disease in mice injected with peripheral blood mononuclear cells (PBMCs). To solve problems, we used humanized major histocompatibility class I- and class II-deficient NOG mice (referred to as NOG-dKO) to evaluate the antitumor effect of anti-programmed death-1 (PD-1) antibody.

EXPERIMENTAL DESIGN

Humanized NOG-dKO mice, in which human PBMCs and human lymphoma cell line SCC-3, or glioblastoma cell line U87 were transplanted, were used as an immunotherapy model to investigate the effect of anti-PD-1 antibody. A biosimilar anti-PD-1 mAb generated in our laboratory was administered to humanized NOG-dKO mice transplanted with tumors.

RESULTS

Within 4 weeks after transplantation, human CD45⁺ cells in antibody-treated mice constituted approximately 70% of spleen cells. The injection of anti-PD-1 antibody reduced by more 50% the size of SCC-3 and U87 tumors. In addition, induction of CTLs against SCC-3 cells and upregulation of natural killer cell activity was observed in the antibody-treated group. Tumor-infiltrating lymphocyte profiling showed that more exhausted marker (PD1⁺TIM3⁺LAG3⁺) positive T cells maintained in anti-PD-1 antibody-treated tumor. A greater number of CD8⁺ and granzyme-producing T cells infiltrated the tumor in mice treated with the anti-PD-1 antibody.

CONCLUSIONS

These results suggest that NOG-dKO mice might serve as a good humanized immunotherapy model to evaluate the efficacy of anti-PD-1 antibody prior to the clinical treatment. Clin Cancer Res; 23(1); 149-58. ©2016 AACR.

Immunological effects of the anti-programmed death-1 antibody on human peripheral blood mononuclear cells

Immune checkpoint antibody-mediated blockade has gained attention as a new cancer immunotherapy strategy. Accumulating evidence suggests that this therapy imparts a survival benefit to metastatic melanoma and non-small cell lung cancer patients. A substantial amount of data on immune checkpoint antibodies has been collected from clinical trials; however, the direct effect of the antibodies on human peripheral blood mononuclear cells (PBMCs) has not been exclusively investigated. In this study, we developed an anti-programmed death-1 (PD-1) antibody (with biosimilarity to nivolumab) and examined the effects of the antibody on PBMCs derived from cancer patients. Specifically, we investigated the effects of the anti-PD-1 antibody on proliferation, cytokine production, cytotoxic T lymphocytes (CTL) and regulatory T cells. These investigations yielded several important results. First, the anti-PD-1 antibody had no obvious effect on resting PBMCs; however, high levels of the anti-PD-1 antibody partly stimulated PBMC proliferation when accompanied by an anti-CD3 antibody. Second, the anti-PD-1 antibody restored the growth inhibition of anti-CD3 Ab-stimulated PBMCs mediated by PD-L1. Third, the anti-PD-1 antibody exhibited a moderate inhibitory effect on the induction of myeloid-derived suppressor cells (MDSCs) by anti-CD3 antibody stimulation. Additionally, the presence of the anti-PD-1 antibody promoted antigen-specific CTL induction, which suggests that combining anti-PD-1 antibody and conventional immunotherapy treatments may have beneficial effects. These results indicate that specific cellular immunological mechanisms are partly responsible for the antitumor effect exhibited by the anti-PD-1 antibody against advanced cancers in clinical trials.

Necrotizing lymphadenitis: a clinicopathological and immunohistochemical study of four familial cases and five recurrent cases

We report the clinicopathological and immunohistological findings of nine cases of necrotizing lymphadenitis, consisting of four cases of familial infection and five cases of recurrence. Fever, cervical lymphadenopathy, leucopenia and swelling of the tonsils are characteristic clinical findings. Morphological features of the lymph nodes include the presence of immunoblasts, plasmacytoid T cells, histiocytes and macrophages, the latter with phagocytized nuclear debris derived from degenerated lymphocytes. However, granulocytes are generally absent. Ultrastructurally, tubuloreticular structures are observed not only in lymphoid cells, but in vascular endothelial cells. Immunological studies of peripheral blood using monoclonal antibodies disclose that CD 8+ (Leu 2a+; suppressor/cytotoxic) cells predominate at the onset, but they gradually decrease with the clinical course and the ratio of CD 4+: CD 8+ (helper:suppressor) increases as the disease progresses. However, in the affected lymph nodes, CD4+ (Leu 2a+: helper/inducer) cells often increase with the clinical progression, but the ratio of CD 4+:CD 8+ in the lymph nodes does not correlate with clinical progression. In addition, Ki-67+CD 8+ cells are more often seen than Ki-67+CD 4+ cells. It is suggested that necrotizing lymphadenitis is an infectious disease in which CD 4+ cells are disrupted and CD 8+ cells undergo transformation to blastoid cells. This results in a change in the ratio of T subsets.

[Studies of specific IgE and IgG antibodies in allergic children. Changes in specific IgE and IgG antibodies to egg white, milk, soybean and mite from children with atopic dermatitis]

Egg, milk, soybean, mite (DF)-specific IgG and IgE antibodies were measured in 276 atopic dermatitis children in whom dietary restrictions had never been done. We recommend cleaning house and bed clothes to decrease number of mites and elimination diet according to clinical symptoms and laboratory findings. After elimination periods (approximately 140 days) the same specific antibodies were examined again. In the patients who improved clinically by elimination of foods, the specific IgG antibodies to the foods decreased significantly. The other patients did not improved clinically suggesting that inadequate elimination diet were done and cleaning house and bed clothes was incomplete and/or other types of allergic reactions might exist.