Normal Immune System Research Articles

The PD-1 and PD-L1 pathway in recurrent respiratory papillomatosis.

Generation of an immunosuppressive microenvironment may enable a persistent human papillomavirus infection in the setting of an otherwise normal immune system. We hypothesized that expression of the T-lymphocyte co-inhibitory receptor programmed death 1 (PD-1) and its ligand PD-L1 would be increased in the recurrent respiratory papillomatosis (RRP) microenvironment compared to normal controls. Case-control study. Formalin-fixed paraffin-embedded respiratory papilloma and normal controls were obtained under institutional review board approval, stained for CD4, CD8, FoxP3, and PD-1, and scored by automated cell count. PD-L1 staining was scored by a blinded pathologist using an adjusted inflammation score that accounted for epithelial and immune infiltrate. Thirty-nine RRP cases and seven controls were studied. All immunologic markers demonstrated significantly increased staining in RRP specimens compared to normal controls (all P < .01). PD-1 correlated with both CD4 (P < .0001) and CD8 (P < .001) cell counts. Epithelial staining for PD-L1 (68%) and PD-L1+ infiltrating immune cells (76%) were observed in the majority of papilloma samples. The strongest staining for PD-L1 was usually observed in the basal papilloma layer adjacent to the immunologic infiltrate in the vascular core. Disease severity inversely correlated with CD8 cell counts (P = .01). A correlation between disease severity and other immunologic markers was not observed. Most RRP specimens demonstrate PD-1 T-lymphocyte infiltration and PD-L1 expression on both papilloma and infiltrating immune cells. This study suggests that this checkpoint pathway may be contributing to local immunosuppression in RRP, and opens the door for clinical trials utilizing PD-blocking monoclonal antibodies. NA Laryngoscope, 128:E27-E32, 2018.

Immune Modulation in Normal Human Peripheral Blood Mononuclear Cells (PBMCs) (Lymphocytes) in Response to Benzofuran-2-Carboxylic Acid Derivative KMEG during Spaceflight

Microgravity and radiation exposure during space flight have been widely reported to induce the suppression of normal immune system function, and increase the risk of cancer development in humans. These findings pose a serious risk to manned space missions. Interestingly, recent studies have shown that benzofuran-2-carboxylic acid derivatives can inhibit the progression of some of these devastating effects on earth and in modeled microgravity. However, these studies had not assessed the impacts of benzofuran-2- carboxylic acid and its derivatives on global gene expression under spaceflight conditions. In this study, the ability of a specific benzofuran-2-carboxylic acid derivative (KMEG) to confer protection from radiation and restore normal immune function was investigated following exposure to space flight conditions on the ISS. Normal human peripheral blood mononuclear cells (lymphocytes) treated with 10 µ g/ml of KMEG together with untreated control samples were flown on Nanoracks hardware on Spacex-3 flight. The Samples were returned one month later and gene expression was analyzed. A 1g-ground control experiment was performed in parallel at the Kennedy spaceflight center. The first overall subtractive unrestricted analysis revealed 78 genes, which were differentially expressed in space flight KMEG, untreated lymphocytes as compared to the corresponding ground controls. However, in KMEG-treated space flight lymphocytes, there was an increased expression of a group of genes that mediate increased transcription, translation and innate immune system mediating functions of lymphocytes as compared to KMEG-untreated samples. Analysis of genes related to T cell proliferation in spaceflight KMEG-treated lymphocytes compared to 1g-ground KMEG- treated lymphocytes revealed six T cell proliferation and signaling genes to be significantly upregulated (p < 0.001) and five related genes were found to be significantly down-regulated. These genes play a significant role in promoting the proliferation of T-lymphocytes, the regulation of membrane trafficking, promote early response, mediating C-myc related proliferation, promote antiapoptotic activity and protects mitochondria from the accumulation of oxidatively damaged membrane proteins. Overall, our analysis indicates that KMEG promotes T- cell proliferation and has an anti-inflammatory effect, thereby increasing immunity and possible protection from chronic inflammation setting which is optimally required during long term space flights.

Abstract 72: Induction of immune tolerance to recombinant immunotoxin LMB-100 using synthetic vaccine particles encapsulating rapamycin

Abstract Recombinant Immunotoxins (RITs) are genetically engineered proteins designed for cancer therapy. LMB-100 is a second generation RIT that is composed of a humanized Fab targeting mesothelin and a de-immunized fragment of Pseudomonas Exotoxin A. Due to the bacterial origin of the toxin, LMB-100 is immunogenic, although less immunogenic than first generation immunotoxins. Almost all patients treated with LMB-100 made anti-drug antibodies (ADAs) after two or more cycles of treatment that neutralized the RIT and greatly lowered efficacy. Kishimoto et al. demonstrated that Synthetic Vaccine Particles containing Rapamycin (SVP-R) inhibited the formation of ADAs, when administered with a foreign protein such as KLH or Pegsiticase. The SVP-R are taken up by macrophages and dendritic cells and increase the number of regulatory T cells in treated mice. Here we evaluated the efficacy of combination therapy of LMB-100 and SVP-R to eradicate mesothelin expressing tumors while preventing ADA formation. To evaluate if SVP-R can prevent ADAs against LMB-100, we immunized immune-competent mice with a combination of SVP-R and RIT and measured ADAs titers by ELISA and by a functional neutralization assay. We found that the treatment reduced ADA titers by more than 99%. To determine if the mice were tolerized to LMB-100, we treated the mice with two doses of SVP-R and six doses of LMB-100 to induce tolerance; and followed by nine challenges of LMB-100 given over 6 weeks. We found that the ADAs were reduced by 98%, indicating development of immunological tolerance to LMB-100. To show that the tolerance is transferable, we tolerized the mice with six doses of SVP-R and LMB-100 and adoptively transferred their splenocytes to naïve recipient mice. The recipient mice were challenged with six doses of LMB-100 and ADA titers were measured. We found that splenocytes from tolerized mice induced a 66% decrease in ADA formation in the recipient mice indicating that the tolerance was mediated by cells of the immune system. To demonstrate that immune suppression is useful in treating tumors, we implanted mouse breast cancer cells expressing human mesothelin into Balb/c mice with a normal immune system and treated them with LMB-100. LMB-100 produced tumor regressions when given before ADAs developed, but was inactive in mice with pre-existing ADAs. However, when mice with preexisting ADAs were treated with LMB-100 and SVP-R, anti-tumor activity was restored and ADAs suppressed (P≤0.0001). SVP-R are being evaluated in humans to prevent ADA to Pegsiticase, an enzyme for refractory gout treatment. Our data indicates that combining SVP-R with LMB-100 should be useful in treating cancer by allowing more treatment cycles and better efficacy. This approach can be used to increase the efficacy of other immunogenic agents such as CAR-T cells, antibody drug conjugates and viral gene therapy vectors Citation Format: Ronit Mazor, Emily King, Takashi Kei Kishimoto, Ira Pastan. Induction of immune tolerance to recombinant immunotoxin LMB-100 using synthetic vaccine particles encapsulating rapamycin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 72. doi:10.1158/1538-7445.AM2017-72

Abstract 3030: Mutant p53-driven metastasis explored utilizing a traceable, conditional osteosarcoma model

Abstract TP53 is the most frequently mutated gene in cancer and missense mutations in particular account for the majority of mutations. Mutant p53 proteins exert oncogenic Gain-of-Function (GOF) properties that contribute to increased migration and invasion in culture and metastasis in vivo. To elucidate how mutant p53 drives metastasis, we developed a traceable somatic osteosarcoma model that initiates with a single p53 mutation (p53R172H or p53R245W), or p53 loss specifically in osteoblasts using Osx-cre. To mark tumor cells, we utilized the mTmG allele which expresses membrane-targeted Tomato (mT) prior to Cre-mediated excision and membrane-targeted green fluorescent protein (mG) after excision so the tumor cells become GFP+ and the stromal cells remain RFP+. In this high penetrant, short latency mouse model, tumor micro-metastasis can be detected by GFP expression in the context of a normal stroma and immune system. The cohort has developed osteosarcoma with complete penetrance and an average survival of 304± 65 day. We observed metastasis in 55% of p53 mutant osteosarcomas which was significantly higher than 26% metastasis observed in p53 null tumors (p&amp;lt;0.01). In p53 mutant osteosarcomas, the metastasis rate was found significantly associated with low p53 copy number. Spectral karyotyping (SKY) on early passage cells derived from somatic p53 mutant tumors exhibited marked aneuploidy with modal chromosome numbers near tetraploid. To characterize the transcriptional profile associated with mutant p53 GOF, we analyzed and compared the RNA-Seq transcriptomes of eight tumors derived from p53R172H mutant mice with eight p53 null tumors. Comparative analysis of gene expression identified a signature of snRNA genes to be strongly associated with mutant p53 gain of function. Functional annotation of upregulated genes in mutant tumors was also highly enriched for chromatin modifying enzymes. These findings contribute to our understanding of the role of mutant p53 GOF in metastasis. Our long term goal is to study how tumor-stromal interactions affect tumor development and metastasis. This understanding will have broad translational significance in diagnosis and treatment of tumors with mutant p53. Citation Format: Rasoul Pourebrahimabadi, Yun Zhang, Mark J. McArthur, Guillermina Lozano. Mutant p53-driven metastasis explored utilizing a traceable, conditional osteosarcoma model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3030. doi:10.1158/1538-7445.AM2017-3030

Abstract 2197: Characterization of immunoliposomes as delivery vehicles for the Rac inhibitor Ehop-016 in HER2 type breast cancer

Abstract Due to the critical need for improved therapeutics against advanced Stage IV breast cancer, we developed and pre-clinically validated the small molecule Ehop-016 as a potential anti-metastatic drug. Ehop-016 is a small molecule inhibitor of the interaction Rac with the guanine nucleotide exchange factor (GEF) Vav2, which consequently decreases invasive actin structures and cellular migration. In a human epidermal growth factor receptor 2 (HER2) type breast cancer model in nude mice, Ehop-016 inhibits mammary tumor growth, angiogenesis, and metastasis. Moreover, Ehop-016 reduces HER2++ cancer cell viability and migration, individually or in combination with anti HER2 or EGFR directed therapeutics. By inhibiting the key signaling intermediate Rac, Ehop-016 has the potential to block signaling downstream of HER2 and EGFRs, as well as signaling via the myriad of receptors that activate Rac, and inhibit cancer progression. Our new results demonstrate that Ehop-016 inhibits both cancer cells and leukocytes in the tumor microenvironment, as well as cytokine levels (IL-6) in mouse plasma. Even though these characteristics are desirable in anticancer agents, systemic therapy with Ehop-016 may adversely affect normal immune system function. Therefore, a strategy was developed for the targeted delivery of Ehop-016 into mammary tumors, using nanoliposomes containing the current breast cancer therapeutic, Trastuzumab, a monoclonal antibody directed at the HER2. We tested various nanoliposome formulations as targeted delivery systems for Ehop-016. First, the encapsulation efficiency of Ehop-016 loaded liposomes was tested using different drug loading methods. To obtain HER2 targeted liposomes, we prepared Trastuzumab-lipid conjugates and incorporated them into the Ehop-016 containing liposomes. The binding, internalization and selectivity of our HER2 targeted delivery system was verified in human metastatic breast cancer cell lines, by using fluorescence microscopy to assess the co-staining of the lipid bilayer and Trastuzumab. In order to evaluate the effectiveness and selectivity of the immunoliposomes in delivering Ehop-016 and inhibiting Rac activity, pull-down assays were performed to detect active Rac-GTP in cells treated with Ehop-016 alone or Trastuzumab-conjugated liposomes with Ehop-016. Results show that the Trastuzumab-conjugated liposomes are more selective at binding to HER2+ breast cancer cells and inhibiting Rac, than treatment with Ehop-016 alone. In summary, our novel delivery system containing Ehop-016 and Trastuzumab has been shown to be effective in breast cancer cells, and needs to be validated in animal models of metastatic breast cancer. The development of this targeted delivery system has implications, not only in the field of breast cancer therapeutics, but may be adapted for the treatment of other diseases, and used to overcome the side effects of current treatments. Citation Format: Michael J. Rivera-Robles, Pablo E. Vivas-Mejia, Linette Castillo-Pichardo, Cornelis Vlaar, Eliud Hernández, Suranganie Dharmawardhane. Characterization of immunoliposomes as delivery vehicles for the Rac inhibitor Ehop-016 in HER2 type breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2197. doi:10.1158/1538-7445.AM2017-2197

Predicting CD4 T-Cell Reconstitution Following Pediatric Hematopoietic Stem Cell Transplantation.

Hematopoietic stem cell transplantation (HSCT) is an increasingly common treatment for children with a range of hematological disorders. Conditioning with cytotoxic chemotherapy and total body irradiation leaves patients severely immunocompromised. T‐cell reconstitution can take several years due to delayed restoration of thymic output. Understanding T‐cell reconstitution in children is complicated by normal immune system maturation, heterogeneous diagnoses, and sparse uneven sampling due to the long time spans involved. We describe here a mechanistic mathematical model for CD4 T‐cell immune reconstitution following pediatric transplantation. Including relevant biology and using mixed‐effects modeling allowed the factors affecting reconstitution to be identified. Bayesian predictions for the long‐term reconstitution trajectories of individual children were then obtained using early post‐transplant data. The model was developed using data from 288 children; its predictive ability validated on data from a further 75 children, with long‐term reconstitution predicted accurately in 81% of the patients.

Interventions for cutaneous molluscum contagiosum.

Molluscum contagiosum is a common skin infection, caused by a virus, which will usually resolve within months in people with a normal immune system. Many treatments have been promoted for molluscum contagiosum but a clear evidence base supporting them is lacking.To assess the effects of management strategies (including waiting for natural resolution) for cutaneous, non-genital molluscum contagiosum in healthy people.We searched the Skin Group Specialised Register (March 2004), the Cochrane Central Register of Controlled Trials (2004, Issue 2), MEDLINE (from 1966 to March 2004), EMBASE (from 1980 to March 2004) and LILACS (from 1982 to March 2004) databases. We also searched reference lists and contacted pharmaceutical companies and experts in the field.Randomised controlled trials for treatment of molluscum contagiosum were investigated. Trials on sexually transmitted molluscum contagiosum and in people with lowered immunity (including those with HIV infection) were excluded.Study selection and assessment of methodological quality were carried out by two independent authors. As similar comparisons between two interventions were not made in more than one study, statistical pooling was not performed.Five studies, with a total number of 137 participants, examined the effects of topical (three studies), systemic and homoeopathic interventions (one study each). Limited evidence was found for sodium nitrite co-applied with salicylic acid compared to salicylic acid alone (risk ratio (RR) 3.50, 95% confidence interval (CI) 1.23 to 9.92). No statistically significant differences were found for topical povidone iodine plus salicylic acid compared to povidone iodine alone (RR of cure 1.67, 95% CI 0.81 to 3.41) or compared to salicylic acid alone. Also no statistically significant differences were found for potassium hydroxide compared to placebo; systemic treatment with cimetidine versus placebo or systemic treatment with calcarea carbonica, a homoeopathic drug, versus placebo (RR 5.57, 95% CI 0.93 to 33.54). Study limitations included no blinding (two studies), many dropouts (three studies) and no intention-to-treat analysis (two studies); small study sizes may have led to important differences being missed. None of the evaluated treatment options were associated with serious adverse effects.No single intervention has been shown to be convincingly effective in treating molluscum contagiosum.

Seroprevalence and molecular evaluation of toxoplasmosis in children with cancer in Khuzestan province, Southwest of Iran.

Toxoplasma gondii is an intracellular parasite with global distribution. Toxoplasmosis in individuals with normal immune system is usually asymptomatic, but in immunocompromised patients may lead to death if not cured. In this study, the prevalence rate of acute and chronic toxoplasmosis in children with cancer was investigated using serological and molecular methods. Blood samples were taken from 372 children with cancer in Shafa hospital in Ahvaz, southwest of Iran. Anti-T. gondii IgG and IgM antibodies were investigated by ELISA. The presence of Toxoplasma in the blood samples was evaluated by Nested PCR. Among 372 children with cancer, 155 (41.7%) were positive for anti-T. gondii IgG antibodies and 24 (6.4%) were positive for anti-T. gondii IgM antibodies, as well. In IgG avidity test, 34 (22%) had antibodies indicating acute phase and 121 (78%) had antibodies indicating chronic phase. The Nested PCR results were showed T. gondii parasite in 34 (100%) patients among 34 IgG antibody-positive patients with acute infection, among 16 IgG antibody-positive patients with chronic infection, 10 patients were indicative of T. gondii and 6 patients were not indicative of T. gondii. A total of 50 cases, 44 (88%) were T. gondii-positive and 6 (12%) were T. gondii-negative in Nested PCR. This study showed high prevalence of toxoplasmosis in children with cancer. Results of serological techniques (ELISA and IgG avidity) had a higher overlap with Nested PCR in identifying T. gondii of seropositive patients.

Abstract A29: Anti-CTLA-4 antibody scFv producing recombinant Bifidobacterium secretes CTLA-4 blocker specifically inside hypoxic tumor and suppresses tumor growth in syngeneic mice model

Abstract Success of immune checkpoint antibody drugs has provided broad perspective in cancer immunotherapy. Anti-PD-1 antibody and anti-CTLA-4 antibody showed notable efficacy and the combination complimentarily enhanced antitumor benefit. Nevertheless, either single-agent therapy or combination therapy is facing immune-related adverse events (irAEs), which is major cause of treatment discontinuation. Also, still large fraction of cancer patients doesn't respond to the antibody immunotherapy. Since non-specific systemic activation of normal immune system by the therapy is one of major reasons to cause the above problems, approaches to target the hypoxic condition of tumors may help increasing the drug's tumor-targeting specificity, which results in minimizing the irAEs and improving the response rate in patients. In an aim to improve anti-cancer drug delivery efficacy, we have been developing in situ Delivery and Production System (i-DPS) by modifying a non-pathogenic anaerobic bacterium, Bifidobacterium, which localizes and proliferates only in the hypoxic environment like solid tumors after intravenous administration, produces anticancer proteins, enzymes or other pharmacologically active molecules selectively at the tumor site. Here we present anti-human CTLA-4 antibody scFv producing i-DPS in cancer immunotherapy, which could be specifically delivered to and amplified only at the hypoxic sites of solid tumors. A series of in vitro assays has been performed to confirm the stable expression and secretion of anti-hCTLA-4 scFv by recombinant Bifidobacterium, the binding affinity of purified anti-hCTLA-4 scFv and the IC50 competing with hCTLA-4/hCD80 or hCD86 interaction as well. Anti-murine CTLA-4 scFv producing Bifidobacterium as surrogate systemically administered to the syngeneic mice model demonstrated significant tumor growth inhibition. Moreover, the combination therapy of anti-mCTLA-4 scFv producing Bifidobacterium and anti-murine PD-1 antibody was more effective than each of monotherapy. It is noteworthy that scFv was only detected in tumor tissue but not in blood proved by immunoprecipitation assay. Altogether, i-DPS for anti-CTLA-4 antibody provide a new promising immune-therapeutic modality to target hypoxic solid tumors and also provide a unique insight for antibody drug delivery in cancer immunotherapy. Citation Format: Koichiro Shioya, Shiro Kataoka, Li Wang, Tomio Matsumura, Hitomi Shimizu, Yasuyoshi Kanari, Yuji Seki, Yuko Shimatani, Minoru Fujimori, Shun'ichiro Taniguchi. Anti-CTLA-4 antibody scFv producing recombinant Bifidobacterium secretes CTLA-4 blocker specifically inside hypoxic tumor and suppresses tumor growth in syngeneic mice model. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A29.

Role of the leukocyte response in normal and immunocompromised host after Clostridium difficile infection

Clostridium difficile is the leading cause of healthcare-associated infections in the United States. Clinically, C. difficile-associated disease can present as asymptomatic colonization, self-limited diarrheal illness or severe colitis (that may result in death). This variability in disease course and outcomes suggests that host factors play an important role as key determinants of disease severity. Currently, there are several scoring indices to estimate severity of C. difficile-associated disease. Leukocytosis and renal failure are considered to be the most important predictors of C. difficile disease severity in hosts with a normal immune system. The degree of leukocytosis which is considered significant for severe disease and how it is scored vary amongst scoring indices. None of the scores have been prospectively validated, and while total WBC count is useful to estimate the magnitude of the host response in most patient populations, in immune-compromised patients like those receiving chemotherapy, solid organ transplant patients or hematopoietic stem cell transplants the WBC response can be variable or even absent making this marker of severity difficult to interpret. Other cellular subsets like neutrophils, eosinophils and lymphocytes provide important information about the host immune status and play an important role in the immune response against C. difficile infection. However, under the current scoring systems the role of these cellular subsets have been underestimated and only total white blood cell counts are taken into account. In this review we highlight the role of host leukocyte response to C. difficile challenge in the normal and immunocompromised host, and propose possible ways that would allow for a better representation of the different immune cell subsets (neutrophils, lymphocytes and eosinophils) in the current scoring indices.

A Case Control Study of Syngeneic Transplantation Versus Autologous Transplantation for Multiple Myeloma: Two Decades of Experience at MD Anderson

INTRODUCTION: High-dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HCT) is the standard of care for eligible patients with newly diagnosed multiple myeloma. However, almost all patients eventually relapse possibly due to incomplete elimination of malignant plasma cells. For patients with an identical twin, syngeneic-HCT provides a tumor-free graft without the risk of graft vs. host disease. We hypothesized that syngeneic-HCT would result in better disease control than auto-HCT. METHODS: We identified 10 patients with multiple myeloma who underwent syngeneic-HCT at our institution from 1994 to 2014. Using a propensity score, we identified 48 controls that received auto-HCT during the same time interval. Matching was done for the year of transplant, age and disease status at auto-HCT (Table 1). Primary endpoint was progression-free survival (PFS). Secondary endpoints were complete remission (CR) rates and overall survival (OS). RESULTS: Baseline characteristics are shown in Table 1. The two groups were well matched, with no significant statistical differences in age, sex, race, stage at diagnosis, lines of therapy received, or disease status prior to transplant. At the time of transplant, 7 (70%) patients in the syngeneic cohort were in first remission, with 3 (30%) having relapsed disease. Similarly, 28 (58%) patients in the autologous cohort were in first remission, with 20 (41%) having relapsed disease (p value 0.49). Patient outcomes are summarized in Table 2. All patients engrafted, with a median time to engraftment of 11 and 10 days, for the syngeneic and auto-HCT cohorts respectively (p=0.22). There was no treatment related mortality in the first 100 days post-transplant in either of the cohorts. In the syngeneic group 8 (80%) patients achieved ≥ CR, 1 achieved very good partial remission (VGPR), and 1 achieved a partial remission (PR), with an overall response rate (ORR) of 100%. Amongst the control group, 18 (37%) achieved ≥ CR, 5 (10%) achieved ≥ VGPR, 21 (43%) achieved ≥PR, 3 (6%) had stable disease and 1 (2%) had disease progression, with an ORR of 91.6%. There was no significant difference in the ORR between the two groups (p=0.21). At the time of last follow-up, a total of 4 (40%) patients had relapsed in the syngeneic cohort, and 31 (65%) had relapsed in the autologous cohort (p=0.15). The median progression free survival (PFS) for the syngeneic cohort was 98.6 months (95% CI from 76-118 months), while the median PFS for auto-HCT cohort was 34.5 months (95% CI from 16-52 months) (p=0.05). Median overall survival (OS) for the syngeneic and auto-HCT cohorts were not reached and 131 months, respectively (p=0.15). The PFS difference was not due to a difference in maintenance therapy after transplant, as 6 (60%) syngeneic patients and 32 (66.7%) auto-HCT (p=0.69) received maintenance therapy respectively. CONCLUSION: Our study shows that patients with multiple myeloma who underwent syngeneic-HCT had a trend to a higher CR rate and longer PFS compared to a matched cohort that underwent auto-HCT. This benefit may be related to the absence of malignant plasma cells in the syngeneic graft, and a normal donor immune system. The efficacy of syngeneic transplants needs to be assessed in a larger number of patients to provide sufficient power to detect clinically meaningful differences with autologous transplants. Disclosures Bashir:Takeda: Consultancy; Spectrum: Consultancy; Takeda: Research Funding; Celgene: Research Funding. Champlin:Ziopharm Oncology: Equity Ownership, Patents & Royalties; Intrexon: Equity Ownership, Patents & Royalties.

Drugs Hypersensitivity Reaction in Patient with Human Immunodeficiency Virus (HIV) Infection

A case of male, 34 years old with a diagnosis of immunodeficiency syndrome resulting from HIV infection with suspected pneumonia in the differential diagnosis of pulmonary tuberculosis relapse, in the course of the disease, patients experienced hypersensitivity reactions to some antibiotics and antituberculosis drugs. Hypersensitivity reactions were exaggerated by immune response to an allergen in a normal immune system. In this case, we found the drug hypersensitivity reactions in patients with immunodeficiency. Until now, the exact underlying mechanism is not fully known but may be due to multifactorial and the dysregulation of the immune system due to HIV infection.

The Frequency of Cryptosporidium spp. in Immunocompromised Patients by Modified Acid-Fast Staining, Cassette Kit and ELISA Methods: Comparison of the Diagnostic Techniques

Background: Cryptosporidiosis has been reported in both immunocompetent and immunocompromised patients from over 40 countries in six continents. Objectives: This study was carried out to determine the prevalence of Cryptosporidium spp. in immunocompromised patients by methods of modified acid fast staining, ELISA and Cassette Kit, and to also compare the three methods. Methods: The patients in different age groups admitted to Bitlis state hospital between June 23, 2011 and January 13, 2015 were enrolled. The study group was composed of 300 immunocompromised volunteer patients and the control group of 100 volunteers with normal immune system. In the study group, patients with hemodialysis, chronic renal failure, diabetes mellitus, diabetes insipidus, and cancer were enrolled. Formalin-ethyl acetate, modified acid fast staining and native-lugol were used for all stool samples; they were also investigated for Cryptosporidium antigens by the ELISA and Cassette Kit. Results: The highest prevalence rate of Cryptosporidium spp. is found to be 11.3%, which is obtained by ELISA and the lowest (0.7%) by Cassette Kit in the study group. All patients with cryptosporidiosis had diarrhea. The highest prevalence rate (20%) was observed in patients with diabetes insipidus and the second highest in patients with chronic renal failure (11.5%) by ELISA. The sensitivities and specificities of Cassette Kit and modified acid fast staining were 5.9%, 100%; and 50%, 100%, respectively. Conclusions: It is concluded that Cryptosporidium spp. should be considered in immunocompromised diarrheal patients and ELISA must be chosen for detection of this parasite. Modified acid fast staining and Cassette Kit techniques could be performed if ELISA is not available. The single use of the Cassette Kit will be inadequate for the diagnosis of cryptosporidiosis.

A Case Control Study of Syngeneic Transplantation Versus Autologous Transplantation for Multiple Myeloma: Two Decades of Experience at MD Anderson

INTRODUCTION:High-dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HCT) is the standard of care for eligible patients with newly diagnosed multiple myeloma. However, almost all patients eventually relapse possibly due to incomplete elimination of malignant plasma cells. For patients with an identical twin, syngeneic-HCT provides a tumor-free graft without the risk of graft vs. host disease. We hypothesized that syngeneic-HCT would result in better disease control than auto-HCT.METHODS:We identified 10 patients with multiple myeloma who underwent syngeneic-HCT at our institution from 1994 to 2014. Using a propensity score, we identified 48 controls that received auto-HCT during the same time interval. Matching was done for the year of transplant, age and disease status at auto-HCT (Table 1). Primary endpoint was progression-free survival (PFS). Secondary endpoints were complete remission (CR) rates and overall survival (OS).RESULTS:Baseline characteristics are shown in Table 1. The two groups were well matched, with no significant statistical differences in age, sex, race, stage at diagnosis, lines of therapy received, or disease status prior to transplant. At the time of transplant, 7 (70%) patients in the syngeneic cohort were in first remission, with 3 (30%) having relapsed disease. Similarly, 28 (58%) patients in the autologous cohort were in first remission, with 20 (41%) having relapsed disease (p value 0.49). Patient outcomes are summarized in Table 2. All patients engrafted, with a median time to engraftment of 11 and 10 days, for the syngeneic and auto-HCT cohorts respectively (p=0.22). There was no treatment related mortality in the first 100 days post-transplant in either of the cohorts. In the syngeneic group 8 (80%) patients achieved ≥ CR, 1 achieved very good partial remission (VGPR), and 1 achieved a partial remission (PR), with an overall response rate (ORR) of 100%. Amongst the control group, 18 (37%) achieved ≥ CR, 5 (10%) achieved ≥ VGPR, 21 (43%) achieved ≥PR, 3 (6%) had stable disease and 1 (2%) had disease progression, with an ORR of 91.6%. There was no significant difference in the ORR between the two groups (p=0.21). At the time of last follow-up, a total of 4 (40%) patients had relapsed in the syngeneic cohort, and 31 (65%) had relapsed in the autologous cohort (p=0.15). The median progression free survival (PFS) for the syngeneic cohort was 98.6 months (95% CI from 76-118 months), while the median PFS for auto-HCT cohort was 34.5 months (95% CI from 16-52 months) (p=0.05). Median overall survival (OS) for the syngeneic and auto-HCT cohorts were not reached and 131 months, respectively (p=0.15). The PFS difference was not due to a difference in maintenance therapy after transplant, as 6 (60%) syngeneic patients and 32 (66.7%) auto-HCT (p=0.69) received maintenance therapy respectively.CONCLUSION:Our study shows that patients with multiple myeloma who underwent syngeneic-HCT had a trend to a higher CR rate and longer PFS compared to a matched cohort that underwent auto-HCT. This benefit may be related to the absence of malignant plasma cells in the syngeneic graft, and a normal donor immune system. The efficacy of syngeneic transplants needs to be assessed in a larger number of patients to provide sufficient power to detect clinically meaningful differences with autologous transplants. [Display omitted] [Display omitted] [Display omitted] DisclosuresBashir:Takeda: Consultancy; Spectrum: Consultancy; Takeda: Research Funding; Celgene: Research Funding. Champlin:Ziopharm Oncology: Equity Ownership, Patents & Royalties; Intrexon: Equity Ownership, Patents & Royalties.

Abstract A050: Cdk5 disruption attenuates tumor PD-L1 expression via regulation of IFN-γ signaling components and promotes antitumor immunity

Abstract In order to escape normal immune surveillance, tumors mimic peripheral tissue tolerance mechanisms such as the expression of programmed cell death-ligand 1 (PD-L1), the inhibition of which can lead to potent anti-tumor responses. Here we show the contribution of cyclin dependent kinase 5 (Cdk5) to immune evasion. Cdk5 is a proline-directed serine/threonine kinase, which is highly expressed in post-mitotic neurons and directs a variety of homeostatic functions from cytoskeletal rearrangement to neurotransmitter signaling. Studies in xenograft models have linked Cdk5 activity to the generation and metabolic activity of primary tumors within the central nervous system (CNS). Here we show that Cdk5, expressed in both murine and human medulloblastoma (MB) cell lines, plays a major role in the ability of MB to avoid immune detection. First, we observed that decreased Cdk5 expression was associated with an increase in the number of infiltrating CD3+ cells in the tumor mass of clinical MB samples. Additionally, using publicly available datasets, we found that decreased Cdk5 expression is correlated with better overall survival or fewer distant metastasis in melanoma, breast cancer, glioma, and lung adenocarcinoma. Next, using a CRISPR/Cas-9 approach, we silenced Cdk5 in a murine model of Sonic Hedgehog (SHH) pathway MB. Rather than causing intrinsic growth defects in MB, interference of Cdk5 activity sensitizes tumors to killing by the normal host immune system in a CD4+ T cell-dependent manner. This rejection is associated with increased IFN-γ expression in the tumor microenvironment, as well as increased PD-L1 expression by myeloid populations in both subcutaneous and intracranial tumors. Mechanistically, we observed an attenuated response to IFN-γ stimulated expression of programmed death ligand 1 (PD-L1) on MB cells. This blunted response was recapitulated when MB cells were treated with Roscovitine, a non-selective Cdk5 inhibitor. Furthermore, using a quantitative global phosphoproteomics approach, we found that Cdk5 knockdown also increased phosphorylation of S-440 and S-443 on interferon regulatory factor binding protein 2 (IRF2BP2), an upstream co-repressor of interferon regulatory factor 2 (IRF-2). Increased phosphorylation of IRF2BP2 corresponded with stable expression of IRF-2 with a concomitant decrease in surface expression of PD-L1. These observations highlight a critical role for Cdk5 in the immune escape mechanisms of primary CNS tumors and provides new therapeutic targets for PD-1/PD-L1 directed immunotherapy. Citation Format: Rodney D. Dorand, Jr., Joseph Nthale, Jay T. Myers, Deborah S. Barkauskas, Stefanie Avril, Steven M. Chirieleison, Tej K. Pareek, Derek W. Abbott, Duncan S. Stearns, John J. Letterio, Alex Y. Huang, Agne Petrosiute. Cdk5 disruption attenuates tumor PD-L1 expression via regulation of IFN-γ signaling components and promotes antitumor immunity [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A050.

A Sixth Modality of Infectious Disease: Contagious Cancer from Devils to Clams and Beyond.

Infectious agents come in many forms, but they have been grouped into five distinct classes of agents: viruses, bacteria, fungi, parasites, and prions. Cancer is not normally on this list. Infectious agents like Human papilloma virus (HPV) or Human T-lymphotropic virus type 1 (HTLV-1) can cause cancers in infected hosts, but these cancers are generated within each new individual from oncogenic changes within the hosts’ own cells, and they stay within that individual. If cancer cells did travel from one individual to another, a normal immune system would be able to recognize them as foreign and reject them. Cancer is thus usually a self-limiting disease—it either regresses or it kills its host, and the death of the host marks the death of the cancer lineage. But this is not always the case. Transmissible cancers have been identified as spreading within two vertebrates, dogs (Canis lupus familiaris) and Tasmanian devils (Sarcophilus harrisii), and more recently, multiple independent lineages of transmissible cancer have been found in four species of bivalves (Fig 1). This is an infectious modality that has significant effects on animals in both the terrestrial and marine environments, as well as in both vertebrates and invertebrates. While large-scale transmission of cancer has not been observed in humans, transmission between humans has been observed on a small scale in a number of circumstances, often in the context of immune suppression. With more research, more cases are likely to be found in humans as well as other animals. Fig 1 Comparison of the known lineages of infectious cancers in natural populations.

The concept of immune surveillance against tumors. The first theories.

The immune system plays a major role in the surveillance against tumors. To avoid attack from the immune system, tumor cells develop different strategies to escape immune surveillance. Evidence of immune surveillance comes from both animal models and clinical observations. Mice with a wide variety of immunodeficiencies have a high rate of tumor incidence and are more susceptible to transplanted or chemical carcinogen-induced tumors. Immunosuppressed patients have a high incidence of tumors. However, many patients develop cancer even in the presence of an apparently normal immune system. This indicates that tumor cells are able to escape immune surveillance. The aim of this review article is to summarize the literature concerning the development of the theory of immune surveillance against tumors; to discuss the evidence for and against this theory, and to discuss the concept of immunoediting. Finally, the current approaches in anti-tumor immunotherapy will be analyzed.

Essential role for the histone acetyltransferase KAT7 in T cell development, fitness, and survival.

Histone acetylation has an important role in gene regulation, DNA replication, and repair. Because these processes are central to the development of the immune system, we investigated the role of a previously unstudied histone acetyltransferase named KAT7 (also known as Myst2 or HBO1) in the regulation of thymopoiesis and observed a critical role in the regulation of conventional and innate-like T cell development. We found that KAT7-deficient thymocytes displayed normal, positive selection and development into mature single-positive αβ thymocytes; however, we observed few peripheral CD4+ or CD8+ T cells. The observed effects did not appear to arise from alterations to DNA replication, the TCR repertoire, or a block in thymocyte maturation and, more likely, was linked to survival defects related to gene deregulation because KAT7 deficiency led to an almost complete and specific loss of global histone-H3 lysine 14 acetylation (H3K14ac). Overall, we demonstrated a nonredundant role for KAT7 in the maintenance of H3K14ac, which is intimately linked with the ability to develop a normal immune system.

Abstract 1479: Preclinical model of human melanoma for evaluation of targeted drug treatment and for immunotherapy validation

Abstract Malignant melanoma accounts for less than 5% of skin cancer cases, yet it represents 75% of deaths from skin cancer. The high mortality rate is due to the malignant, metastatic nature of the disease and resistance to chemotherapeutic treatments. Most mouse melanoma models have not fully recapitulated the histopathology of the disease and its metastatic nature. At NCI's Center for Advanced Preclinical Research (CAPR), we have adapted the HGF/SF; CDK4R24C transgenic mouse model to an optimized allograft transplant model for preclinical therapeutic studies in primary and metastatic melanoma. This genetically engineered mouse-derived Allograft (GDA) model recapitulates the features of the original GEM, including the epithelioid histopathology and key marker expression of human melanoma. It is an efficient and tractable tool for monitoring of both tumor growth and therapeutic responses in primary and metastatic melanoma in the context of a normal immune system. Additionally, aberrant expression of c-Met and upregulation of the downstream signaling pathway in HGF-GDA tumors is relevant for targeted therapeutics in melanoma. Thus, the model is a useful platform for evaluating therapies that target tumor cells and/or immunomodulatory pathways in intervention or adjuvant settings. Although drugs such as the c-Met inhibitor crizotinib and the MEK inhibitor trametinib were potent in cell culture, PD analyses of short-term (4-6 hour) treatment with small molecule therapies indicated that treatment incompletely suppresses the pathway in vivo compared to the corresponding primary cell line, and does not inhibit tumor growth. Therefore the HGF-GDA can be exploited to examine combination treatments that either prevent feedback activation of downstream pathway nodes in vivo, or modify alternate pathways, such as immunomodulatory targets. Hence, we are currently exploring rational combinations of oncogene-targeted therapy with immune-targeted therapy, for example, combined trametinib and anti-CTLA4 antibody treatment. In the HGF-GDA, complete response was observed in a subgroup of mice treated with anti-CTLA-4, i.e. established tumors fully regressed, yet the durable response and increased survival time (based on tumor volume) was not enhanced by concurrent treatment with trametinib. Future treatment studies will involve alternative regimens. Additionally, since metastasis, not the primary tumor, leads to progression of melanoma in patients, we have characterized a primary tumor resection model in which only metastatic disease is treated. Lung metastases develop after resection of the HGF-GDA primary tumor, which may be treated in an intervention or adjuvant setting. Therefore we evaluated the effect on survival of the same combination therapy (trametinib and anti-CTLA-4) we previously used to treat the primary tumor, but as adjuvant treatment for the metastatic melanoma model. Citation Format: Rajaa El Meskini, Michelle Gumprecht, Alan Kulaga, Anthony Iacovelli, Terry Van Dyke, Chi-Ping Day, Glenn Merlino, Zoe Weaver Ohler. Preclinical model of human melanoma for evaluation of targeted drug treatment and for immunotherapy validation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1479.

Gestational age, mode of birth and breastmilk feeding all influence acute early childhood gastroenteritis: a record-linkage cohort study.

BackgroundAcute gastroenteritis (AGE) is a leading cause of infectious morbidity in childhood. Clinical studies have implicated caesarean section, early birth and formula feeding in modifying normal gut microbiota development and immune system homeostasis in early life. Rates of early birth and cesarean delivery are also increasing worldwide. This study aimed to investigate the independent and combined associations of the mode and timing of birth and breastmilk feeding with AGE hospitalisations in early childhood.MethodsPopulation-based record-linkage study of 893,360 singleton livebirths of at least 33 weeks gestation without major congenital conditions born in hospital, New South Wales, Australia, 2001–2011. Using age at first AGE hospital admission, Cox-regression was used to estimate the associations for gestational age, vaginal birth or caesarean delivery by labour onset and formula-only feeding while adjusting for confounders.ResultsThere were 41,274 (4.6 %) children admitted to hospital at least once for AGE and the median age at first admission was 1.4 years. Risk of AGE admission increased with decreasing gestational age (37–38 weeks: 15 % increased risk, 33–36 weeks: 25 %), caesarean section (20 %), planned birth (17 %) and formula-only feeding (18 %). The rate of AGE admission was highest for children who were born preterm by modes of birth other than vaginal birth following the spontaneous onset of labour and who received formula-only at discharge from birth care (62–78 %).ConclusionsVaginal birth following spontaneous onset of labour at 39+ weeks gestation with any breastfeeding minimised the risk of gastroenteritis hospitalisation in early childhood. Given increasing trends in early planned birth and caesarean section worldwide, these results provide important information about the impact obstetric interventions may have on the development of the infant gut microbiota and immunity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12887-016-0591-0) contains supplementary material, which is available to authorized users.