Anorectal Neisseria gonorrhoeae infections in women with and without reported anal sex and sex workers in sexual health centres in the Netherlands: a retrospective cohort study

BACKGROUND

Control of Neisseria gonorrhoeae infection (gonorrhoea) depends on effective testing strategies. Anorectal testing in women is often done on indication of anal sex; however, anorectal infections are seen with and without anal exposure, possibly caused by autoinoculation. This study aims to enhance understanding of anorectal infections in women, by identifying risk factors for anorectal diagnosis.

METHODS

In this retrospective cohort study we used national surveillance data from Dutch sexual health centres from Jan 1, 2016, to Dec 31, 2021. We included cisgender women having sex with men who were tested urogenitally and anorectally for gonorrhoea. Due to different testing policies, we identified three groups: women who had not reported recent anal sex (in the past 6 months), women who had reported recent anal sex, and sex workers. Extracted data for analyses included demographics, sexual behaviour, and diagnosis of a sexually transmitted infection (STI). Per group, multivariable models using Firth's penalised maximum likelihood logistic regression were constructed, identifying determinants of anorectal gonorrhoea among all women and among gonorrhoea-positive women only. Variables included in model construction were age, education level, migration background, number of partners, condom use, partner notification, STI symptoms, having a partner who has sex with men (MSM) or a migrant partner, previous STI test, anal sex, and chlamydia and gonorrhoea diagnoses per anatomical location.

FINDINGS

In total, 117 693 women were included: 43 757 women without reported recent anal sex, 51 728 women with reported recent anal sex, and 22 208 sex workers. In all three groups, around 2% of women were gonorrhoea positive, and 70% or more of women had an anorectal infection. The strongest determinant of anorectal gonorrhoea was a concurrent urogenital gonorrhoea diagnosis (adjusted odds ratios [aOR] 782 [95% CI 605-1018]) among women without reported recent anal sex (612 [490-768] among women with reported recent anal sex, and 464 [335-652] among sex workers). Among gonorrhoea-positive women, determinants of anorectal gonorrhoea were urogenital and anorectal chlamydia co-infection (aOR 2·03 [95% CI 1·38-3·02], for women without reported anal sex) and migration background (1·44 [1·02-2·06], for women with reported anal sex). Determinants among sex workers were condomless sex (2·43 [1·55-3·82]), anal sex (1·71 [1·10-2·66]), MSM or migrant partner (1·78 [1·13-2·79]), and urogenital and anorectal chlamydia co-infection (2·28 [1·11-5·14]).

INTERPRETATION

These findings support the possibility of an autoinoculation process from the urogenital to the anorectal location due to the very strong correlation between urogenital and anorectal gonorrhoea, and due to the similarity of results across all three groups. Current testing strategies could miss anorectal infections, which should be considered when developing gonorrhoea prevention and control guidelines.

FUNDING

None.

Systematic review of the effectiveness of innovative, gamified interventions for cognitive training in paediatric acquired brain injury

Effectiveness of innovative, gamified interventions (i.e., Augmented Reality, Computer-Based Cognitive Retraining [CBCR], and Virtual Reality [VR] in conjunction with a Serious Game) for cognitive training in paediatric ABI was evaluated. Studies were identified on PsycINFO, PubMed and Scopus; last searched 4 January 2022. Eligibility criteria were participants diagnosed with ABI and aged ≤ 18 years, experimental intervention to train cognition, cognition assessed pre- and post-intervention at: (1) The level of function, or (2) The level of activity, and written in English. ROB 2 and ROBINS-I were utilised to assess risk of bias. Extracted study characteristics were methods, participants, interventions, outcomes, and results. Seven studies were included, comprising six CBCR studies and one VR study, with 182 participants. Following CBCR: (1) Improvements were observed in several cognitive functions, but there was inconsistent evidence; (2) Improvements were reported in attention and executive functions (EF) at home and at school. Following VR: (1) Improvements were observed in attention and EF; (2) Not evaluated. Due to the small number of included studies with (relatively) small and heterogeneous samples, only a cautious interpretation of the evidence was provided. There is a need for carefully designed studies with more attention to inter-individual differences and generalisation to daily life.

The Malnutrition Awareness Scale for community-dwelling older adults: Development and psychometric properties

BACKGROUND & AIMS

Qualitative studies suggest that malnutrition awareness is poor in older adults. The aim of this study was to develop a questionnaire to quantitatively assess malnutrition awareness in community-dwelling older adults aged 60+ years.

METHODS

The Malnutrition Awareness Scale (MAS) was developed based on the awareness phase of the Integrated-Change model, and included four domains: knowledge, perceived cues, risk perceptions, and cognizance. Twenty-six scale items were developed using results from mainly qualitative research and the expertise of the authors. Items were piloted in 10 Dutch older adults using the Thinking Aloud method to optimize wording. In a feasibility study, annoyance, difficulty and time to complete the MAS and its comprehensibility were tested. After final revisions, the MAS was applied to a large sample to test its psychometric properties (i.e., inter-item correlations, Cronbach's alpha, score distribution) and relevance of the items was rated on a 5-point scale by 12 experts to determine content validity.

RESULTS

The feasibility study (n = 42, 55 % women, 19 % 80+ y) showed that the MAS took 12 ± 6 min to complete. Most participants found it not (at all) annoying (81 %) and not (at all) difficult (79 %) to complete the MAS, and found it (very) comprehensible (83 %). Psychometric analyses (n = 216, 63 % women, 28 % 80+ y) showed no redundant items, but two items correlated negatively with other items, and one correlated very low. After removal, the final MAS consists of 23 items with a min-max scoring range from 0 to 22 (with higher scores indicating higher awareness) and an overall Cronbach's alpha of 0.67. The mean MAS score in our sample (n = 216) was 14.8 ± 3.2. The lowest obtained score was 6 (n = 3) and the highest 22 (n = 1), indicating no floor or ceiling effects. Based on the relevance rating, the overall median across all 22 items was 4.0 with IQR 4.0-5.0.

CONCLUSION

The Malnutrition Awareness Scale is a novel, feasible and reliable tool with good content validity to quantitively assess malnutrition awareness in community-dwelling older adults. The scale is now ready to identify groups with poor malnutrition awareness, as a basis to start interventions to increase malnutrition knowledge and awareness.

The sex difference in self-rated health among older Turkish and Moroccan migrants in the Netherlands: an exploratory study of contributing determinants

BACKGROUND

Although being a woman and having a migration background are strong predictors of poor self-rated health among (older) adults, research on the sex difference in self-rated health among (older) migrants remains limited. This study therefore aims to investigate this topic and explore the contributing role of determinants of self-rated health.

METHODS

Cross-sectional data from 360 Turkish-Dutch and Moroccan-Dutch adults aged 55-65 as part of the Longitudinal Aging Study Amsterdam (LASA) were used. Self-rated health (good versus poor) was measured by a single item question. Univariate age-adjusted logistic regression analysis was used to investigate the sex difference in self-rated health and the contribution of sex differences in sensitivity (strength of the association) and/or exposure (prevalence) to socio-demographic, social, lifestyle or health-related determinants of self-rated health.

RESULTS

Women had a 0.53 times lower odds (95%CI:0.40-0.82, p = 0.004) on good self-rated health compared to men. Women more often having a lower education level, living alone and having a higher prevalence of depressive symptoms, chronic diseases and especially functional limitations contributed to the lower self-rated health among women. In contrast, men were more sensitive to the impact of memory complaints, depressive symptoms, visual difficulties and functional limitations.

CONCLUSIONS

Older Turkish-Dutch and Moroccan-Dutch women have a significant lower self-rated health compared to men. Women having a higher exposure to both socio-demographic and health-related determinants of self-rated health, which contributed to the sex difference. Future research should take these differences in self-rated health and determinants between women and men into account when investigating health among older migrants.

Timed adoptive T cell transfer during chemotherapy in patients with recurrent platinum-sensitive epithelial ovarian cancer

BACKGROUND

The presence of T cells and suppressive myeloid cells in epithelial ovarian cancer (EOC) correlate with good and bad clinical outcome, respectively. This suggests that EOC may be sensitive to adoptive cell therapy with autologous tumor-infiltrating lymphocytes (TIL), provided that immunosuppression by myeloid-derived suppressor cells and M2 macrophages is reduced. Platinum-based chemotherapy can alleviate such immunosuppression, potentially creating a window of opportunity for T cell-based immunotherapy.

METHODS

We initiated a phase I/II trial (NCT04072263) in patients with recurrent platinum-sensitive EOC receiving TIL during platinum-based chemotherapy. TILs were administered 2 weeks after the second, third and fourth chemotherapy course. Patients were treated in two cohorts with or without interferon-α (IFNa), as conditioning and TIL support regimen. The primary endpoint was to evaluate the feasibility and safety according to CTCAE V.4.03 criteria and the clinical response and immune modulatory effects of this treatment were evaluated as secondary endpoints.

RESULTS

Sixteen patients were enrolled. TIL could be successfully expanded for all patients. TIL treatment during chemotherapy without IFNa (n=13) was safe but the combination with IFNa added to the chemotherapy-induced toxicity with 2 out of 3 patients developing thrombocytopenia as dose-limiting toxicity. Fourteen patients completed treatment with a full TIL cycle and were further evaluated for clinical and immunological response. Platinum-based chemotherapy resulted in reduction of circulating myeloid cell numbers and IL-6 plasma levels, confirming its immunosuppression-alleviating effect. Three complete (CR), nine partial responses and two stable diseases were recorded, resulting in an objective response rate of 86% (Response Evaluation Criteria In Solid Tumors V.1.1). Interestingly, progression free survival that exceeded the previous platinum-free interval was detected in two patients, including an exceptionally long and ongoing CR in one patient that coincided with sustained alleviation of immune suppression.

CONCLUSION

TIL therapy can be safely combined with platinum-based chemotherapy but not in combination with IFNa. The chemotherapy-mediated reduction in immunosuppression and the increase in platinum-free interval for two patients warrants further exploration of properly-timed TIL infusions during platinum-based chemotherapy, possibly further benefiting from IL-2 support, as a novel treatment option for EOC patients.

Neoantigen Targetability in Progressive Advanced Melanoma

PURPOSE

The availability of (neo)antigens and the infiltration of tumors by (neo)antigen-specific T cells are crucial factors in cancer immunotherapy. In this study, we aimed to investigate the targetability of (neo)antigens in advanced progessive melanoma and explore the potential for continued T-cell-based immunotherapy.

EXPERIMENTAL DESIGN

We examined a cohort of eight patients with melanoma who had sequential metastases resected at early and later time points. Antigen-presenting capacity was assessed using IHC and flow cytometry. T-cell infiltration was quantified through multiplex immunofluorescence. Whole-exome and RNA sequencing were conducted to identify neoantigens and assess the expression of neoantigens and tumor-associated antigens. Mass spectrometry was used to evaluate antigen presentation. Tumor recognition by autologous T cells was assessed by coculture assays with cell lines derived from the metastatic lesions.

RESULTS

We observed similar T-cell infiltration in paired early and later metastatic (LM) lesions. Although elements of the antigen-presenting machinery were affected in some LM lesions, both the early and later metastasis-derived cell lines were recognized by autologous T cells. At the genomic level, the (neo)antigen landscape was dynamic, but the (neo)antigen load was stable between paired lesions.

CONCLUSIONS

Our findings indicate that subsequently isolated tumors from patients with late-stage melanoma retain sufficient antigen-presenting capacity, T-cell infiltration, and a stable (neo)antigen load, allowing recognition of tumor cells by T cells. This indicates a continuous availability of T-cell targets in metastases occurring at different time points and supports further exploration of (neo)antigen-specific T-cell-based therapeutic approaches for advanced melanoma.

Can mindful eating buffer against the influence of neighbourhood fast food exposure on unhealthy food intake?

A food-abundant environment is associated with unhealthy food intake, but not everyone is affected to the same degree. Mindful eating, which is eating with attention and awareness, has been associated with less external eating and less food cravings, and could act as a protective factor against influences from the food environment. The current study aimed to investigate whether the association between exposure to fast-food around the home and unhealthy food intake was moderated by mindful eating. The study was conducted in 1086 Dutch adults of 55 years and older of the Longitudinal Aging Study Amsterdam study. The mindful eating domains (Mindful Eating Behavior Scale) were tested as moderating variables in the linear regression models with absolute and relative density of fast-food outlets in the neighbourhood (400, 800 and 1600m) as independent variables and unhealthy food intake (snacks (g/d)) and saturated fat as a percentage of total energy intake (en%)) as dependent variable. Bootstrapping with 5000 samples using the pick-a-point approach showed that after adjustments, only two out of 48 interactions terms were statistically significant: Eating with Awareness (EwA) and Eating without Distraction (EwD) moderated the positive association between the relative density of fast-food outlets and saturated fat (en%) respectively in a buffer of 800m (interaction EwA: B = -0.84, 95% CI [-1.46; -0.22]) and in a buffer of 1600m (interaction EwD: B = -0.82, 95% CI [-1.61; -0.04]). The results of the current study indicate that mindful eating cannot buffer against the influence of the fast-food abundant environment on unhealthy food intake. Future research is needed to confirm these findings, for example in younger populations.

Perspectives of older women in the Netherlands: identifying motivators and barriers for healthy lifestyles and determinants of healthy aging

BACKGROUND

Women have a higher life expectancy than men but experience more years with physical disabilities in daily life at older ages, especially women with a migration background. This pinpoints older women as an important target group for strategies that stimulate healthy lifestyle, which benefits healthy aging. Our study investigates motivators and barriers for healthy lifestyles and perspectives on determinants of healthy aging of older women. This provides essential information for developing targeted strategies.

METHODS

Data was collected by semi-structured digital interviews from February till June 2021. Women aged 55 years and older living in the Netherlands (n = 34) with a native Dutch (n = 24), Turkish (n = 6) or Moroccan (n = 4) migration background were included. Two main subjects were investigated: (1) motivators and barriers on their current lifestyles regarding smoking, alcohol consumption, physical activity, diet and sleep and (2) perspectives on determinants of healthy aging. Interviews were analyzed using Krueger's framework.

RESULTS

Personal health was the most common motivator for a healthy lifestyle. In addition, peer pressure and being outdoors were specific motivators for physical activity. Bad weather conditions and personal dislike to be active were specific barriers. The social environment, personal preferences and personal belief to compensate with other healthy lifestyle behaviors were barriers for low alcohol consumption. Personal preferences (liking unhealthy food and not making time) were the main barriers for a healthy diet. Sleep was not perceived as a form of lifestyle behavior, but rather as a personal trait. Since there were no smokers, specific barriers were not mentioned. For Turkish-Dutch and Moroccan-Dutch women, additional barriers and motivators were culture and religion. These were strong motivators to abstain from alcohol consumption and smoking, but a barrier for a healthy diet. With regard to perspectives on determinants of healthy aging, positive views on aging and being physically active were perceived as most important. Women often wanted to increase their physical activity or healthy diet to stimulate healthy aging. Among Turkish-Dutch and Moroccan-Dutch women, healthy aging was also perceived as something in the hands of God.

CONCLUSIONS

Although motivators and barriers for a healthy lifestyle and perspectives on healthy aging vary for distinct lifestyles, personal health is a common motivator across all lifestyles. Having a migration background added culture and religion as distinct barriers and motivations. Strategies to improve lifestyle among older women should therefore have a tailored, culture sensitive approach (if applicable) for distinct lifestyle factors.

1322 DEVELOPMENT OF A CORE OUTCOME SET FOR NUTRITIONAL INTERVENTION STUDIES IN OLDER ADULTS WITH MALNUTRITION AND THOSE AT RISK

Background

Malnutrition (i.e., protein-energy malnutrition) in older adults is associated with significant complications and increased mortality, highlighting the need for effective treatments. Many randomised controlled trials (RCTs) testing the effectiveness of nutritional interventions for the treatment of malnutrition showed mixed results and there is a need for meta-analyses. However, evidence synthesis is hampered by the wide variety of outcomes and assessment methods in RCTs. This project, led by EuGMS Special Interest Group Nutrition, aims to develop a Core Outcome Set (COS) for nutritional intervention studies in older adults with malnutrition and those at risk.

Methods

The project consists of five phases: 1) a scoping review (completed) to identify frequently used outcomes in published RCTs and select additional patient-reported outcome measures (PROMs). Patient and Public Involvement (PPI) representatives have been involved to provide feedback on the proposed list of outcomes resulting from the review and PROMs; 2) a modified Delphi Survey whereby experienced researchers and health care professionals working in the field of malnutrition in older adults will be invited to rate the importance of the proposed outcomes; 3) a consensus meeting to discuss and agree what critical outcomes need to be included in the COS; 4) a systematic review to determine how each COS outcome should be measured and a second consensus meeting; 5) a dissemination and implementation phase.

Conclusions

The result of this project will be a COS that should be included in any RCT testing the effectiveness of interventions to tackle malnutrition in older people as a minimum. This COS will facilitate comparison of RCT results, will promote efficient use of research resources and might reduce bias in measurement of the outcome and publication bias. Ultimately, the COS will support clinical decision making by identifying the most effective approaches for treating and preventing malnutrition in older adults.

A combined cowhide/gelatine soft tissue simulant for ballistic studies

The ballistic resistance of a combined soft tissue simulant was studied, consisting of gelatine as a simulant for human muscle tissue and tanned cowhide (leather) as a simulant for human skin. The simulant was manufactured by applying cowhide to liquid ballistic gelatine, as the gelatine solidified in its mould. Combining a skin and muscle tissue simulant in this adhered way opens the possibility to produce purpose-built proxies for human body parts in ballistic studies or for forensic shooting incident reconstructions. Ballistic resistance of adhered cowhide - (bonded) to solidifying ballistic gelatine - was compared to that of the same material applied on gelatine blocks in loose condition. Ballistic resistance of tanned cowhide was found to be more consistent in adhered condition. This enhanced consistency is a benefit, increasing reproducibility of results in ballistic studies. Additionally, two ways to assess ballistic resistance of a skin simulant were described and compared. Logistic regression, from a number of measured velocities and associated (non)perforations is recommended for testing ballistic resistance.

Tumor-Infiltrating T Cells Can Be Expanded Successfully from Primary Uveal Melanoma after Separation from Their Tumor Environment

Purpose

To evaluate whether expanded tumor-infiltrating lymphocytes (TILs) can be obtained from primary uveal melanoma (UM) for potential use as adjuvant treatment in patients at risk of developing metastatic disease.

Design

Experimental research study.

Participants

Freshly obtained primary UM from 30 patients.

Methods

Three different methods were used to expand TILs: (1) direct culture from small fragments of fresh tumor tissue, (2) single-cell tissue preparation by enzymatic digestion and subsequent enrichment of mononuclear cells, and (3) selection of CD3⁺ T cells using magnetic beads. Surface expression of costimulatory and inhibitory T-cell markers and T-cell reactivity against autologous tumor cells was assessed. Clinical, histopathologic, genetic, and immunologic characteristics of the tumors were compared with the capacity to expand TILs and with their reactivity against autologous tumor cells.

Main Outcome Measures

The feasibility of expanding TILs from primary UM, testing their reactivity to autologous UM cells, and evaluating the impact of an immunomodulatory environment.

Results

Direct culture of tumor parts led to successful TIL culture in 4 of 22 tumors (18%), enrichment of mononuclear cells gave rise to TILs in 5 of 12 tumors (42%), while preselection of CD3⁺ T cells with magnetic beads resulted in TIL expansion in 17 of 25 tumors (68%). In 8 of 17 tumors (47%), the TIL cultures comprised UM-reactive T cells. The presence of UM-reactive T cells among TILs was not related to clinical, histologic, genetic, or immunological tumor characteristics. Interestingly, RNA-Seq analysis showed that approximately half of the UM tumors displayed an increased expression of immunomodulatory molecules related to T-cell suppression, such as galectin 3, programmed death-ligand 1, cytotoxic T-lymphocyte-associated protein 4, indoleamine 2,3-dioxygenase 1, and lymphocyte activating 3, potentially explaining why T cells require optimal removal of tumor components for expansion.

Conclusions

The need to separate TILs from their tumor microenvironment for their successful expansion and the presence of UM-reactive T cells among TILs suggests that these UM-reactive T cells are strongly suppressed in vivo and that UM is immunogenic. These findings indicate that adoptive TIL therapy could be an option as an adjuvant treatment in primary UM patients at high risk of developing metastatic disease.

Enhanced antigen cross-presentation in human colorectal cancer-associated fibroblasts through upregulation of the lysosomal protease cathepsin S

Background

Cross-presentation of exogenous antigens in HLA-class I molecules by professional antigen presenting cells (APCs) is crucial for CD8+ T cell function. Recent murine studies show that several non-professional APCs, including cancer-associated fibroblasts (CAFs) also possess this capacity. Whether human CAFs are able to cross-present exogenous antigen, which molecular pathways are involved in this process and how this ultimately affects tumor-specific CD8+ T cell function is unknown.

Methods

In this study, we investigated the ability of human colorectal cancer (CRC)-derived CAFs to cross-present neoantigen-derived synthetic long peptides (SLPs), corresponding to tumor-derived mutant peptides, and how this affects tumor-specific T-cell function. Processing of the SLP was studied by targeting components of the cross-presentation machinery through CRISPR/Cas9 and siRNA-mediated genetic ablation to identify the key molecules involved in fibroblast-mediated cross-presentation. Multispectral flow cytometry and killing assays were performed to study the effect of fibroblast cross-presentation on T cell function.

Results

Here, we show that human CRC-derived CAFs display an enhanced capacity to cross-present neoantigen-derived SLPs when compared with normal colonic fibroblasts. Cross-presentation of antigens by fibroblasts involved the lysosomal protease cathepsin S. Cathepsin S expression by CAFs was detected in situ in human CRC tissue, was upregulated in ex vivo cultured CRC-derived CAFs and showed increased expression in normal fibroblasts after exposure to CRC-conditioned medium. Cognate interaction between CD8+ T cells and cross-presenting CAFs suppressed T cell function, reflected by decreased cytotoxicity, reduced activation (CD137) and increased exhaustion (TIM3, LAG3 and CD39) marker expression.

Conclusion

These data indicate that CAFs may directly suppress tumor-specific T cell function in an antigen-dependent fashion in human CRC.

Bovine parafilariosis - New autochthonous cases from Germany and summary of recent reports from Europe

Bovine parafilariosis is an emerging fly-borne disease in central Europe, characterized by seasonal occurrence of hemorrhagic exudations ('bleeding spots') from the end of winter to end of summer. In two cases from Germany reported here, one animal of a small herd in Bavaria and 20 animals on a farm in Baden-Württemberg presented bleeding spots from late March and late April 2020, respectively. Exudate samples from both cases were positive for larvated Parafilaria eggs. Examination of the skin and trimmed tissue after slaughter of the animal from Bavaria resulted in the collection of 11 nematodes (two males, eight females, one specimen in fragments). The animal's carcass presented typical yellow-greenish areas and bloody spots on the subcutaneous tissue of the flesh side of the skin. The nematodes were microscopically determined as Parafilaria bovicola. Basic morphometric measurements of two (one intact) male and six female nematodes are within the ranges of published data; length (male/female) 28.8/48.0-64.5 mm; width, 397.6 μm/430.7-527.6 μm; distance of cervical papillae to anterior end, 177.6/248.9-337.4; left spiculum/right spiculum (male), 365.3-379.4/149.5-180.3 μm; gubernaculum 45.0-48.1 μm; distance of vulva to anterior end (female), 37.3-66.0 mm. In order to gain information on P. bovicola in its vector, 91 cattle-visiting Musca autumnalis flies were collected from the affected animal in Bavaria (36 flies) and from co-pastured animals (55 flies) for PCR analysis and sequencing. A total of 14 flies were PCR-positive for filarial DNA, and sequencing of a fragment of the cox1 gene resulted in identification of P. bovicola (n = 10) and Thelazia gulosa (n = 5). This report presents further cases of bovine parafilariosis in Germany, provides morphometric data on male and female P. bovicola nematodes retrieved from cattle and identified DNA of P. bovicola and T.gulosa in M. autumnalis flies collected at a site of occurrence of bovine parafilariosis.

Significant variation in histopathological assessment of endoscopic resections for Barrett's neoplasia suggests need for consensus reporting: propositions for improvement

Endoscopic resection (ER) is an important diagnostic step in management of patients with early Barrett's esophagus (BE) neoplasia. Based on ER specimens, an accurate histological diagnosis can be made, which guides further treatment. Based on depth of tumor invasion, differentiation grade, lymphovascular invasion, and margin status, the risk of lymph node metastases and local recurrence is judged to be low enough to justify endoscopic management, or high enough to warrant invasive surgical esophagectomy. Adequate assessment of these histological risk factors is therefore of the utmost importance. Aim of this study was to assess pathologist concordance on these histological features on ER specimens and evaluate causes of discrepancy. Of 62 challenging ER cases, one representative H&E slide and matching desmin and endothelial marker were digitalized and independently assessed by 13 dedicated GI pathologists from 8 Dutch BE expert centers, using an online assessment module. For each histological feature, concordance and discordance were calculated. Clinically relevant discordances were observed for all criteria. Grouping depth of invasion categories according to expanded endoscopic treatment criteria (T1a and T1sm1 vs. T1sm2/3), ≥1 pathologist was discrepant in 21% of cases, increasing to 45% when grouping diagnoses according to the traditional T1a versus T1b classification. For differentiation grade, lymphovascular invasion, and margin status, discordances were substantial with 27%, 42%, and 32% of cases having ≥1 discrepant pathologist, respectively. In conclusion, histological assessment of ER specimens of early BE cancer by dedicated GI pathologists shows significant discordances for all relevant histological features. We present propositions to improve definitions of diagnostic criteria.

Germline ATM variants predispose to melanoma: a joint analysis across the GenoMEL and MelaNostrum consortia

PURPOSE

Ataxia-Telangiectasia Mutated (ATM) has been implicated in the risk of several cancers, but establishing a causal relationship is often challenging. Although ATM single-nucleotide polymorphisms have been linked to melanoma, few functional alleles have been identified. Therefore, ATM impact on melanoma predisposition is unclear.

METHODS

From 22 American, Australian, and European sites, we collected 2,104 familial, multiple primary (MPM), and sporadic melanoma cases who underwent ATM genotyping via panel, exome, or genome sequencing, and compared the allele frequency (AF) of selected ATM variants classified as loss-of-function (LOF) and variants of uncertain significance (VUS) between this cohort and the gnomAD non-Finnish European (NFE) data set.

RESULTS

LOF variants were more represented in our study cohort than in gnomAD NFE, both in all (AF = 0.005 and 0.002, OR = 2.6, 95% CI = 1.56-4.11, p < 0.01), and familial + MPM cases (AF = 0.0054 and 0.002, OR = 2.97, p < 0.01). Similarly, VUS were enriched in all (AF = 0.046 and 0.033, OR = 1.41, 95% CI = 1.6-5.09, p < 0.01) and familial + MPM cases (AF = 0.053 and 0.033, OR = 1.63, p < 0.01). In a case-control comparison of two centers that provided 1,446 controls, LOF and VUS were enriched in familial + MPM cases (p = 0.027, p = 0.018).

CONCLUSION

This study, describing the largest multicenter melanoma cohort investigated for ATM germline variants, supports the role of ATM as a melanoma predisposition gene, with LOF variants suggesting a moderate-risk.

356 Personalized immunotherapy by adoptive T cell transfer during chemotherapy with or without interferon-alpha in patients with recurrent platinum-sensitive epithelial ovarian cancer

Background

Epithelial ovarian cancer (EOC) is considered an immunogenic tumor, as illustrated by the clear correlation between T-cell infiltration and overall survival. This suggests that patients with EOC may be eligible for immunotherapy including adoptive cell therapy with autologous Tumor Infiltrating Lymphocytes (TIL). However, immunosuppressive cells including myeloid derived suppressor cells an regulatory T cells are also abundant in EOC and may need to be targeted simultaneously to achieve the full potential of the infused TIL. Carboplatin-paclitaxel chemotherapy (CPC) reduces the number of immunosuppressive cells in cervical cancer patients,1 creating a window-of-opportunity for TIL to exert their full effector function. Interferon-alpha further supports infused TIL. A phase I/II trial (NCT04072263) was initiated to study the feasibility and safety of TIL during CPC with or without additional interferon-alpha in patients with recurrent platinum-sensitive EOC.

Methods

Fifteen patients with recurrent platinum-sensitive EOC received 6 cycles of CPC intravenously every 3 weeks and TIL intravenously 2 weeks after the 2nd,3rd and 4th CPC cycle. Pegylated-interferon-alpha was added in the second cohort for 12 weeks, starting one week before the first TIL infusion. Patients who received 3 TIL infusions were evaluable. The primary endpoint was feasibility and safety of TIL administration during CPC with or without interferon-alpha. As secondary endpoints signs of activity, underlying mechanisms, immunomodulation, and T-cell reactivity were studied.

Results

Thirteen patients were available for analysis. Median age 63 years (range, 29–77). TIL could be successfully expanded for all patients. Treatment with TIL during CPC was safe and did not add toxicity. Addition of IFNα resulted in grade 3 leucopenia and grade 3 trombocytopenia in the first 2 patients and was therefore omitted in subsequent patients. CPC alleviated the immunosuppressive status, reflected by reduced plasma IL-6 levels and circulating myeloid-cell numbers, while lymphocytes numbers are not affected. This was most prominently at 1–2 weeks after the 2nd CPC and is suggested to reflect improved conditions promoting intra-tumoral T-cell reactivity. Objective responses were observed in 10/13 (77%) patients and 3 patients had stable disease. Interestingly, in at least one patient the ongoing platinum-free interval of 25 months far exceeds the first platinum-free interval of 8 months after similar CPC. In depth studies on immune modulation by chemotherapy and by TIL/Interferon-alpha, and correlations between TIL phenotype and clinical outcome are ongoing and will be presented.

Conclusions

Combined treatment with CP chemotherapy and properly timed TIL may result in clinical benefit for patients with EOC.

Acknowledgements

The unrestricted funding of the trial by Ovacure is greatly acknowledged.

Trial Registration

The trial is registered at www.clinicaltrials.gov under number NCT04072263.

Reference

Welters MJ, van der Sluis TC, van Meir H, Loof NM, van Ham VJ, van Duikeren S, Santegoets SJ, Arens R, de Kam ML, Cohen AF, van Poelgeest MI, Kenter GG, Kroep JR, Burggraaf J, Melief CJ, van der Burg SH. Vaccination during myeloid cell depletion by cancer chemotherapy fosters robust T cell responses. Sci Transl Med 2016;8(334):334ra52. doi: 10.1126/scitranslmed.aad8307

Ethics Approval

This study was approved by Leiden University Medical Center‘s Ethics Board; approval number L18-012 and the Central Committee on Research Involving Human Subjects; approval number NL63434.000.17.

Low-dose interferon-alpha preconditioning and adoptive cell therapy in patients with metastatic melanoma refractory to standard (immune) therapies: a phase I/II study

BACKGROUND

Adoptive cell therapy (ACT) with tumor-reactive T cells has shown consistent clinical efficacy. We evaluated the response to ACT in combination with interferon alpha (IFNa) preconditioning in patients with stage IV metastatic melanoma, most of which were progressive on cytotoxic T-lymphocyte-associated protein 4 and/or programmed cell death protein 1 checkpoint blockade therapy.

METHODS

Thirty-four patients were treated with ex vivo expanded tumor reactive T cells, derived from mixed lymphocyte autologous tumor cultures, or with autologous tumor-infiltrating lymphocytes and evaluated for clinical response. Clinical and immunological parameters associated with response were also evaluated.

RESULTS

Best overall response defined as clinical benefit, comprising either complete response, partial response or stable disease >6 months, was observed in 29% of the patients. Forty-three per cent of the 14 immunotherapy-naïve patients and 20% of the 20 patients progressive on prior immunotherapy benefited from ACT. The overall survival (OS) was 90% versus 28.6% at 1 year and 46.7% versus 0% at 3 years follow-up, of responder and non-responder patients, respectively. Median OS was 36 versus 7 months, respectively. IFNa pretreatment resulted in leukopenia, neutropenia and lymphopenia, which was sustained during the treatment in clinical responders and associated with response. Differences in antigen specificity, but not in phenotype, cytokine profile or CD8+ T cell number of the ACT products correlated with clinical response. Cross-reactivity of the ACT products to one or more allogeneic human leukocyte antigen-matched melanoma cell lines was associated with short OS after treatment while the ACT products of very long-term survivors showed no cross-reactivity but recognized patient-specific neoantigens.

CONCLUSION

This study demonstrates that ACT in combination with a mild IFNa preconditioning regimen can induce clinical benefit even in immunotherapy pretreated patients, although with lower success than in immunotherapy-naïve patients. ACT products comprising neoantigen reactivity may be more effective.

POS0370 TYPE I INTERFERON PATHWAY ASSAYS IN PATIENTS WITH RHEUMATIC AND MUSCULOSKELETAL DISEASES - SYSTEMATIC LITERATURE REVIEW (SLR) AND DEVELOPMENT OF CONSENSUS TERMINOLOGY FROM A EULAR TASKFORCE

Background:

The interferon (IFN) pathway is a complex system with multiple proteins and diverse downstream effects on gene and protein expression. IFNs have been implicated in multiple RMDs. Despite significant potential, IFN assays have not progressed into clinical practice.

Objectives:

To perform a SLR on IFN assays in RMDs and propose a consensus terminology.

Methods:

OvidMedline, Embase and Web of Science were searched for reports of IFN and RMDs up to October 2019. Information about the properties of assays measuring type I IFN and measures of truth were extracted and summarised. Terminology was agreed through an interactive consensus process with reference to the existing evidence.

Results:

10037 abstracts were identified. 275 fulfilled eligibility criteria, and were used for data extraction. Some used more than one technique to measure IFN-I pathway activation. Hence, 275 papers generated data on 393 methods. There was great heterogeneity in the methods used and presentation of results. IFN-I pathway activation was measured using: qPCR (n=121), immunoassays (n=101), microarray (n=69), reporter cell assay (n=38), DNA methylation (n=14), flow cytometry (n=14), cytopathic effect assay (n=11), RNA sequencing (n=9), Plaque reduction assay (n=8), Nanostring (n=5), bisulphite sequencing (n=3). All papers fulfilled Face Validity. Due to lack of gold standard for IFN-I pathway activation, evidence of criterion validity was variable. Concurrent validity was presented for n=150 assays. The terminology used to describe aspects of type I IFN pathway activation was not consistent, so a consensus terminology for IFN research (Table 1) was proposed by the taskforce.

Table 1.

Consensus terminology

TermAbbreviationDefinitionInterferonIFNProteins with anti-viral activity; IFNs are mediators of an anti-viral response. They belong to the Type I, Type II and Type III IFN families.Type I interferonIFN-IThe IFNs alpha, beta, omega, kappa, epsilon, secreted by any nucleated cell, and binding to the IFNAR, which is expressed on any nucleated cell.Type II interferonIFN-IIIFN gamma, mostly secreted by T cells, binding to the IFNGR, which is expressed on most leucocytes.Type III interferonIFN-IIIIFN lambda, which are structurally more similar to IL-10 but share downstream signalling and gene expression with IFN-I.Interferon-stimulated genesISGsGenes whose expression is known to be upregulated by any kind of IFN. Individual ISGs may not exclusively represent Type I IFN pathway activation.Type I Interferon pathway activationAny evidence for function of the components of the Type I IFN pathway. This includes: secretion of a Type I IFN protein, binding to the IFNAR, initiation of JAK/STAT signalling pathways, expression of IFN-stimulated genes, expression of IFN-stimulated proteins.Type I interferon pathway assayAn assay measuring one or more components of the Type I IFN pathway at a molecular or functional level.Interferon stimulated gene expression signatureA qualitative description of coordinated expression of a set of ISGs that is indicative of Type I IFN pathway activation.Interferon stimulated gene expression scoreA quantitative variable derived from expression of a defined set of ISGs that is indicative of Type I IFN pathway activation.Interferon stimulated protein scoreA variable derived from expression of a defined set of soluble biomarkers known to be upregulated by IFN, although not specific for Type I IFN.InterferonopathyMonogenic diseases in which there is constitutive Type I IFN pathway activation with a causal role in pathology. The clinical picture may resemble rheumatic musculoskeletal diseases. However, most diseases with IFN pathway activation are not Interferonopathies.

Conclusion:

Diverse methods have been reported as IFN assays and these differ in what elements of type IFN-I pathway activation they measure. The taskforce consensus terminology on type I IFN reporting should be considered for research and clinical applications.

Disclosure of Interests:

Agata Burska: None declared, Javier Rodriguez Carrio: None declared, Philip G Conaghan: None declared, Willem A Dik: None declared, Robert Biesen: None declared, Maija-leena Eloranta: None declared, Giulio Cavalli: None declared, Marianne Visser: None declared, Dimitrios Boumpas: None declared, George Bertsias: None declared, Marie Wahren-Herlenius: None declared, Jan Rehwinkel: None declared, Marie-Louise Frémond: None declared, Mary K. Crow Consultant of: AstraZeneca, Bristol Meyers Squibb, Lilly, Shannon Pharmaceuticals, Grant/research support from: Gilead, Lars Ronnblom Consultant of: AstraZeneca, Edward Vital Speakers bureau: GSK, Consultant of: AURINIA, SANDOZ, GSK, AstraZeneca, Roche, Modus, Grant/research support from: AstraZeneca, Marjan Versnel: None declared

A higher protein intake at breakfast and lunch is associated with a higher total daily protein intake in older adults: a post-hoc cross-sectional analysis of four randomised controlled trials

BACKGROUND

A protein intake of 30-40 g per meal is suggested to maximally stimulate muscle protein synthesis in older adults and could therefore contribute to the prevention of sarcopenia. Protein intake at breakfast and lunch is often low and offers a great opportunity to improve daily protein intake. Protein, however, is known for its satiating effects. Therefore, we explored the association between the amount of protein intake at breakfast and lunch and total daily protein intake in older adults.

METHODS

Protein intake was assessed by a 3-day food record in 498 community dwelling older adults (≥55 years) participating different lifestyle interventions. Linear mixed model analysis was used to examine the association between protein intake at breakfast or lunch and total daily protein intake, adjusted for sex, age, body mass index, smoking status, study and total energy intake.

RESULTS

After adjustment for potential confounders, a 10 g higher protein intake at breakfast was associated with a 3.2 g higher total daily protein intake (P = 0.008) for males and a 4.9 g (P < 0.001) higher total daily protein intake for females. A 10 g higher protein intake at lunch was associated with a 3.7 g higher total daily protein intake (P < 0.001) for males, and a 5.8 g higher total daily protein intake (P < 0.001) for females.

CONCLUSIONS

A higher protein intake at breakfast and lunch is associated with a higher total daily protein intake in community dwelling older adults. Stimulating a higher protein intake at breakfast and lunch might represent a promising nutritional strategy to optimise the amount of protein per meal without compromising total daily protein intake.

Complete genome sequence of ornithogalum virus 3

Ornithogalum thyrsoides, a widely cultivated bulbous ornamental plant endemic to South Africa, has significant commercial value as a pot plant and for the production of cut flowers. However, infection by viruses threatens the success of commercial cultivation, as symptoms negatively affect the appearance of the plant and flowers. To date, four Ornithogalum-infecting viruses have been reported. Complete genome sequence data are available for three of these viruses, but the genome of the potyvirus ornithogalum virus 3 (OV3) has not been fully sequenced. In this study, the complete sequence of OV3 was determined by high-throughput sequencing (HTS) and validated by Sanger sequencing. Based on recognition of protease cleavage patterns and multiple sequence alignments with closely related viruses, the polyprotein of OV3 was predicted to be proteolytically cleaved to produce 10 mature peptides containing domains conserved in members of the genus Potyvirus. Phylogenetic analysis and species demarcation criteria confirm the previous classification of OV3 as a member of a separate species in this genus. This is the first report of a complete genome sequence of OV3.

Simplified Monopalmitoyl Toll-like Receptor 2 Ligand Mini-UPam for Self-Adjuvanting Neoantigen-Based Synthetic Cancer Vaccines

Synthetic vaccines, based on antigenic peptides that comprise MHC-I and MHC-II T-cell epitopes expressed by tumors, show great promise for the immunotherapy of cancer. For optimal immunogenicity, the synthetic peptides (SPs) should be adjuvanted with suitable immunostimulatory additives. Previously, we have shown that improved immunogenicity in vivo is obtained with vaccine modalities in which an SP is covalently connected to an adjuvanting moiety, typically a ligand to Toll-like receptor 2 (TLR2). SPs were covalently attached to UPam, which is a derivative of the classic TLR2 ligand Pam₃ CysSK₄ . A disadvantage of the triply palmitoylated UPam is its high lipophilicity, which precludes universal adoption of this adjuvant for covalent modification of various antigenic peptides as it renders the synthetic vaccine insoluble in several cases. Here, we report a novel conjugatable TLR2 ligand, mini-UPam, which contains only one palmitoyl chain, rather than three, and therefore has less impact on the solubility and other physicochemical properties of a synthetic peptide. In this study, we used SPs that contain the clinically relevant neoepitopes identified in a melanoma patient who completely recovered after T-cell therapy. Homogeneous mini-UPam-SP conjugates have been prepared in good yields by stepwise solid-phase synthesis that employed a mini-UPam building block pre-prepared in solution and the standard set of Fmoc-amino acids. The immunogenicity of the novel mini-UPam-SP conjugates was demonstrated by using the cancer patient's T-cells.

Phase I/II study protocol to assess safety and efficacy of adoptive cell therapy with anti-PD-1 plus low-dose pegylated-interferon-alpha in patients with metastatic melanoma refractory to standard of care treatments: the ACTME trial

INTRODUCTION

Treatment with anti-PD-1 immunotherapy does not lead to long-lasting clinical responses in approximately 60% of patients with metastatic melanoma. These refractory patients, however, can still respond to treatment with tumour infiltrating lymphocytes (TIL) and interferon-alpha (IFNa). A combination of TIL, pegylated-interferon-alpha (PEG-IFNa) and anti-PD-1 is expected to provide a safe, feasible and effective therapy for patients with metastatic melanoma, who are refractory to standard of care treatment options.

METHODS AND ANALYSIS

Patients are treated in two phases. In phase I, the safety of the combination TIL and anti-PD-1 is assessed (cohort 1) according to CTCAE 4.03 criteria. Subsequently, the safety of cotreatment with PEG-IFNa is tested in cohort 2. The efficacy will be evaluated in the second phase of the trial. Efficacy is evaluated according to RECIST 1.1 and immune-related response criteria. Clinical and immunological parameters will be evaluated for their relation with clinical responsiveness.

ETHICS AND DISSEMINATION

Ethical approval of the trial was obtained from the Central Committee on Research Involving Human Subjects in the Netherlands. The trial results will be shared with the scientific community at (inter)national conferences and by publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03638375; Pre-results.

The SpaTemp cohort: 168 nondysplastic Barrett's esophagus surveillance patients with and without progression to early neoplasia to evaluate the distribution of biomarkers over space and time

The ReBus cohort is a matched nested case-control cohort of patients with nondysplastic (ND) Barrett's esophagus (BE) at baseline who progressed (progressors) or did not progress (nonprogressors) to high-grade dysplasia (HGD) or cancer. This cohort is constructed using the most stringent inclusion criteria to optimize explorative studies on biomarkers predicting malignant progression in NDBE. These explorative studies may benefit from expanding the number of cases and by incorporating samples that allow assessment of the biomarker over space (spatial variability) and over time (temporal variability). To (i) update the ReBus cohort by identifying new progressors and (ii) identify progressors and nonprogressors within the updated ReBus cohort containing spatial and temporal information. The ReBus cohort was updated by identifying Barrett's patients referred for endoscopic work-up of neoplasia at 4 tertiary referral centers. Progressors and nonprogressors with a multilevel (spatial) endoscopy and additional prior (temporal) endoscopies were identified to evaluate biomarkers over space and over time. The original ReBus cohort consisted of 165 progressors and 723 nonprogressors. We identified 65 new progressors meeting the same strict selection criteria, resulting in a total number of 230 progressors and 723 matched nonprogressors in the updated ReBus cohort. Within the updated cohort, 61 progressors and 107 nonprogressors (mean age 61 ± 10 years) with a spatial endoscopy (median level 3 [2-4]) were identified. 33/61 progressors and 50/107 nonprogressors had a median of 3 (2-4) additional temporal endoscopies. Our updated ReBus cohort consists of 230 progressors and 723 matched nonprogressors using the most strict selection criteria. In a subgroup of 168 Barrett's patients (the SpaTemp cohort), multiple levels have been sampled at baseline and during follow-up providing a unique platform to study spatial and temporal distribution of biomarkers in BE.

Poor oral health and incidence of disability: results from studies of older people in the UK and USA

Background

To examine the association between oral health markers and disability 4 years later in two population-based studies of older people in the UK and USA.

Methods

Analyses were conducted in the British Regional Heart Study (BRHS) comprising older men (n = 2147) and the Health, Aging and Body Composition (HABC) Study comprising American older men and women (n = 3075). Data from a 4-year follow up period were used. Oral health measures included tooth loss, periodontal disease, dry mouth, and self-rated oral health. Mobility limitations and Activities of Daily Living (ADL) were markers of disability. Logistic regression was performed and analyses were adjusted for confounders (age, socioeconomic position, lifestyle factors, and chronic diseases).

Results

Over a 4-year follow-up, 15% of subjects in the BRHS and 19% in the HABC Study developed mobility limitations. In both studies, 12% of participants developed ADL problems. In the BRHS, tooth loss (complete and partial), periodontal disease, dry mouth and accumulation of oral health problems were associated with an increased risk of developing mobility limitations after adjustment for confounders (partial tooth loss, OR = 1.86, 95% CI 1.18-2.94, ≥3 dry mouth symptoms, OR = 1.97, 95%CI 1.25-3.09). Similar results were observed for the risk of developing ADL problems. In the HABC Study, complete tooth loss and accumulation of oral health problems were associated with greater risk of incident mobility limitations (OR = 1.77, 95%CI 1.13-2.76; OR = 1.18, 95% CI 1.02-1.37, respectively). Moreover, self-rated oral health was associated with increased risk of ADL problems, after adjustment for confounders.

Conclusions

Poor oral health was associated with increased risk of developing disability in community-dwelling older people. Screening tools of oral health may be helpful in identifying oral health problems, improving oral health status and promoting health and good quality of life.

Key messages

Poor oral health is associated with a higher risk of developing disability in later life. This highlights the importance of oral health on maintaining independence in older people.

Abstract CT194: Low-dose Interferon-alpha pre-conditioning and adoptive cell therapy in metastatic melanoma patients refractory to standard (immune) therapies - a phase 1/2 study

Background: Adoptive cell therapy (ACT) with tumor-reactive T cells has shown consistent clinical efficacy. We evaluated the response to ACT in combination with interferon alpha (IFNa) preconditioning in stage IV metastatic melanoma patients, most of which were progressive on CTLA-4 and/or PD-1 checkpoint blockade therapy.

Methods: Thirty-four patients were treated with ex vivo expanded tumor reactive T cells, derived from mixed-lymphocyte-autologous tumor cultures, or with autologous tumor-infiltrating lymphocytes and evaluated for clinical response. Clinical and immunological parameters associated with response were also evaluated.

Results: Best overall response defined as clinical benefit, comprising either complete response, partial response or stable disease for more than 6 months, was observed in 29% of the patients. Six of the 14 (43%) immunotherapy naïve patients and 4 of the 20 (20%) patients progressive on prior immunotherapy benefited from ACT. The overall survival (OS) was 90% versus 28.6% at 1 year and 46.7% versus 0% at 3 years follow-up, of clinical responder and non-responder patients, respectively. Median OS was 36 versus 7 months, respectively. IFNa pre-treatment resulted in leuko-, neutro- and lymphopenia, which was sustained during the treatment in clinical responders and associated with response. Differences in antigen-specificity, but not in phenotype, cytokine profile, or CD8+ T cell number of the ACT products correlated with clinical response. Cross-reactivity of the ACT products to one or more allogeneic HLA-matched melanoma cell lines was associated with short OS after treatment while the ACT products of very long-term survivors showed solely recognition of patient-specific neo-antigens.

Conclusion: This study demonstrates that ACT in combination with a mild IFNa preconditioning regimen can induce clinical benefit even in immunotherapy pre-treated patients, albeit with lower success than in immunotherapy naïve patients. ACT products comprising neo-antigen reactivity may be more effective.

Future Perspectives: As a substantial percentage of the infused T cells expressed one or more inhibitory checkpoint molecules (CTLA-4, PD-1, or TIM-3), we started a new trial combining ACT and anti-PD-1 (ACTME trial; NCT03638375). The phase Ia of this trial was just completed with nine immunotherapy pre-treated patients showing that the combined treatment is feasible and safe. Updated and accumulated disease response data will be presented.

Citation Format: Monique K. van der Kooij, Els M. Verdegaal, Marten Visser, Carolien E. van der Minne, Linda de Bruin, Pauline Meij, Anton G. Terwisscha van Scheltinga, Marij J. Welters, Saskia J. Santegoets, Noel F. de Miranda, Inge C. Roozen, Gerrit-Jan Liefers, Ellen Kapiteijn, Sjoerd H. van der Burg. Low-dose Interferon-alpha pre-conditioning and adoptive cell therapy in metastatic melanoma patients refractory to standard (immune) therapies - a phase 1/2 study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT194.

Neoantigen-specific immunity in low mutation burden colorectal cancers of the consensus molecular subtype 4

Background

The efficacy of checkpoint blockade immunotherapies in colorectal cancer is currently restricted to a minority of patients diagnosed with mismatch repair-deficient tumors having high mutation burden. However, this observation does not exclude the existence of neoantigen-specific T cells in colorectal cancers with low mutation burden and the exploitation of their anti-cancer potential for immunotherapy. Therefore, we investigated whether autologous neoantigen-specific T cell responses could also be observed in patients diagnosed with mismatch repair-proficient colorectal cancers.

Methods

Whole-exome and transcriptome sequencing were performed on cancer and normal tissues from seven colorectal cancer patients diagnosed with mismatch repair-proficient tumors to detect putative neoantigens. Corresponding neo-epitopes were synthesized and tested for recognition by in vitro expanded T cells that were isolated from tumor tissues (tumor-infiltrating lymphocytes) and from peripheral mononuclear blood cells stimulated with tumor material.

Results

Neoantigen-specific T cell reactivity was detected to several neo-epitopes in the tumor-infiltrating lymphocytes of three patients while their respective cancers expressed 15, 21, and 30 non-synonymous variants. Cell sorting of tumor-infiltrating lymphocytes based on the co-expression of CD39 and CD103 pinpointed the presence of neoantigen-specific T cells in the CD39⁺CD103⁺ T cell subset. Strikingly, the tumors containing neoantigen-reactive TIL were classified as consensus molecular subtype 4 (CMS4), which is associated with TGF-β pathway activation and worse clinical outcome.

Conclusions

We have detected neoantigen-targeted reactivity by autologous T cells in mismatch repair-proficient colorectal cancers of the CMS4 subtype. These findings warrant the development of specific immunotherapeutic strategies that selectively boost the activity of neoantigen-specific T cells and target the TGF-β pathway to reinforce T cell reactivity in this patient group.

Psychosocial counselling for intended parents who opt for donor sperm treatment: which topics do they find relevant?

Objective: This study aimed to explore which topics intended parents who opt for donor sperm treatment find relevant to discuss in psychosocial counselling. Background: The choice for donor sperm treatment has psychosocial implications for intended parents and therefore psychosocial counselling is advised as an integral part of DST. To date, little is known about which topics intended parents find relevant to discuss in psychosocial counselling. Methods: We conducted 25 semi-structured in-depth interviews between 2015 and 2017 with heterosexual men and women, lesbian women and single women who opted for donor sperm treatment and had a counselling session as part of their intake. They were recruited through three Dutch fertility centres, three network organisations and by snowball sampling. Results: Intended parents found it relevant to discuss the following seven topics in psychosocial counselling: the decision to opt for donor sperm treatment, choosing a sperm donor, coping with questions from family and friends, non-genetic parenthood, single motherhood, openness and disclosure, and future contact between the child and half-siblings. Conclusion: We recommend that counsellors take a more active role in bringing up the topics found in our study and that a clear distinction is made between counselling with the aim to screen intended parents and counselling with the aim to offer guidance.

Complete genome sequence of a novel polerovirus in Ornithogalum thyrsoides from South Africa

Ornithogalum thyrsoides, commonly known as chincherinchee, is an indigenous ornamental plant widely cultivated in South Africa. It is commercially valued as a flowering pot plant and for the production of cut flowers. Virus infections resulting in the development of severe necrotic mosaic symptoms threaten the success of commercial cultivation. The virome of an O. thyrsoides plant displaying necrotic mosaic symptoms was determined using high-throughput sequencing (HTS). In this plant, ornithogalum mosaic virus and ornithogalum virus 3 were identified, as well as a previously unknown virus. The full genome sequence of this virus was confirmed by Sanger sequencing using overlapping amplicons combined with rapid amplification of cDNA ends (RACE). Based on genome organisation and phylogenetic analysis, this novel virus can be classified as a polerovirus.

Joint action malnutrition in the elderly (MaNuEL) knowledge hub: summary of project findings

PURPOSE

The Joint Action Malnutrition in the Elderly (MaNuEL) Knowledge Hub was established to extend scientific knowledge, strengthen evidence-based practice, build a sustainable, transnational network of experts and harmonize research and clinical practice in the field of protein-energy malnutrition in older persons. This paper aims to summarize the main scientific results achieved during the 2-year project and to outline the recommendations derived.

METHODS

22 research groups from seven countries (Austria, France, Germany, Ireland, Spain, The Netherlands and New Zealand) worked together on 6 relevant domains of malnutrition-i.e. prevalence, screening, determinants, treatment, policy measures and education for health care professionals-making use of existing datasets, evidence and expert knowledge.

RESULTS

Four systematic reviews, six secondary data analyses of existing cohort and intervention studies, two web-based surveys and one Delphi study were performed. In addition, a scoring system to rate malnutrition screening tools and a theoretical framework on the aetiology of malnutrition in older persons were developed. Based on these activities and taking existing evidence into consideration, 13 clinical practice, 9 research and 4 policy recommendations were developed. The MaNuEL Toolbox was created and made available to effectively distribute and disseminate the MaNuEL results and recommendations.

CONCLUSIONS

The MaNuEL Knowledge Hub successfully achieved its aims. Results and recommendations will support researchers, healthcare professionals, policy-makers as well as educational institutes to advance their efforts in tackling the increasing problem of protein-energy malnutrition in the older population.

The Amsterdam ReBus progressor cohort: identification of 165 Barrett's surveillance patients who progressed to early neoplasia and 723 nonprogressor patients

Patient selection is suboptimal in most studies focused on identifying biological markers for neoplastic progression in Barrett's esophagus (BE). This study aims to describe a stringently selected community-based case-control cohort of non-dysplastic BE (NDBE) patients who progressed to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) and BE patients who never progressed to be used for future biomarker studies. We identified all patients referred for endoscopic work-up of BE neoplasia at three tertiary referral centers for treatment of BE neoplasia between 2000 and 2013. We performed a detailed registration of any endoscopic surveillance history before neoplastic progression. Controls were selected from a retrospective BE surveillance registration in 10 community hospitals. A total of 887 patients were referred for endoscopic work-up of BE neoplasia. Based on predefined selection criteria, we identified 165 progressor patients (82% men; mean age 55 years ± 10.4) with a baseline endoscopy demonstrating NDBE > 2 years before neoplastic progression. Using the same predefined selection criteria, 723 nonprogressor patients (67% men; mean age 57 years ± 11.3) with >2 years of endoscopic surveillance were identified. Median length of the BE segment was 5 cm (IQR 4-7) in progressors and 4 cm (IQR 2-6) in controls. Median duration of surveillance was 89 months (IQR 54-139) in progressors and 76 months (IQR 47-116) in nonprogressors. Paraffin embedded biopsies are available for biomarker research in all patients. Ethical approval was obtained and material transfer agreements were signed with all 58 contributing pathology labs. This is the largest community-based case-control cohort of BE patients with and without progression to early neoplasia. The stringent selection criteria and the availability of paraffin embedded biopsy specimens make this a unique cohort for biomarker studies.

Facing privacy in neuroimaging: removing facial features degrades performance of image analysis methods

Background

Recent studies have created awareness that facial features can be reconstructed from high-resolution MRI. Therefore, data sharing in neuroimaging requires special attention to protect participants’ privacy. Facial features removal (FFR) could alleviate these concerns. We assessed the impact of three FFR methods on subsequent automated image analysis to obtain clinically relevant outcome measurements in three clinical groups.

Methods

FFR was performed using QuickShear, FaceMasking, and Defacing. In 110 subjects of Alzheimer’s Disease Neuroimaging Initiative, normalized brain volumes (NBV) were measured by SIENAX. In 70 multiple sclerosis patients of the MAGNIMS Study Group, lesion volumes (WMLV) were measured by lesion prediction algorithm in lesion segmentation toolbox. In 84 glioblastoma patients of the PICTURE Study Group, tumor volumes (GBV) were measured by BraTumIA. Failed analyses on FFR-processed images were recorded. Only cases in which all image analyses completed successfully were analyzed. Differences between outcomes obtained from FFR-processed and full images were assessed, by quantifying the intra-class correlation coefficient (ICC) for absolute agreement and by testing for systematic differences using paired t tests.

Results

Automated analysis methods failed in 0–19% of cases in FFR-processed images versus 0–2% of cases in full images. ICC for absolute agreement ranged from 0.312 (GBV after FaceMasking) to 0.998 (WMLV after Defacing). FaceMasking yielded higher NBV (p = 0.003) and WMLV (p ≤ 0.001). GBV was lower after QuickShear and Defacing (both p < 0.001).

Conclusions

All three outcome measures were affected differently by FFR, including failure of analysis methods and both “random” variation and systematic differences. Further study is warranted to ensure high-quality neuroimaging research while protecting participants’ privacy.

Key Points

• Protecting participants’ privacy when sharing MRI data is important.

• Impact of three facial features removal methods on subsequent analysis was assessed in three clinical groups.

• Removing facial features degrades performance of image analysis methods.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06459-3) contains supplementary material, which is available to authorized users.

Olfactory and gustatory functioning and food preferences of patients with Alzheimer's disease and mild cognitive impairment compared to controls: the NUDAD project

Our aim is to compare olfactory and gustatory function and food preferences of patients with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD) with controls. We included 22 patients with MCI, 30 patients with AD and 40 controls and assessed olfactory threshold, odor discrimination and odor identification (Sniffin’ Sticks), gustatory functioning (Taste Strips), and food preferences (Macronutrient and Taste Preference Ranking Task). Linear regression analyses were used to study associations of five cognitive domains or AD biomarkers with olfactory functioning. Groups did not differ in olfactory threshold, gustatory function and food preferences. Patients with MCI and AD scored lower on odor discrimination and identification than controls. Poorer memory, but no other cognitive domain, was associated with poorer odor discrimination and odor identification, but not with odor threshold. No associations with AD biomarkers were found. In conclusion, patients with MCI and AD have poorer odor discrimination and identification ability than controls, but similar detection thresholds. This is likely a consequence of poorer memory rather than directly caused by AD pathology.

P2638Preeclampsia is preceded by changes in the cardiovascular function

Objective

We hypothesized that preeclampsia is preceded by early CVF changes. We evaluated the eventual difference between patients who develop preeclampsia and those who stayed normotensives. Secondly we searched for a link between CVF changes and development of preeclampsia.

Methods

This prospective study, included 260 normotensive primiparous women, referred for routinely control to the Cardiology section. At week 22 of gestation and 1 year after delivery were performed: Office blood pressure (OBP), blood and urine lab test. Cardiac index (CI) and systemic vascular resistance index (SVRI) through impedance cardiography. Wave pulse velocity (PWV) through pressure signals. According to the evolution during pregnancy patients were assigned to one of 3 groups: G1 preeclampsia:. G2 Gestational hypertension G3 Normotensive. Statistic tests: one-way analysis of variance and the Bonferroni post-hoc test.

Results

12 patients evolved to preeclamsia, 18 to gestational hypertension and 230 remained normotensive. G1 had significantly lower value of CI in both measurements and higher values of OBP, SVRPI and WPV comparing to G3. G2 always showed intermediate values between G1 and G2. The median age of the population was 25 ≠ 4 years old. By logistic regression analysis WPV and SVRI at 22 week of gestation were predictors of preeclampsia. (p<0.05)

Patient Characteristics Characteristics G1 G2 G3 p<0.05 Systolic, mmHg OBP* 128±10 120±9 107±10 0.001 Diastolic, mmHg OBP* 84±6 75±7 66±6 0.001 Systolic mmHg OBP** 128±11 117±10 114±8 0.01 Diastolic, mmHg OBP** 77±7 71±6 70±6 0.09 WPV, m/sec* 10±4 7±0.8 5.6±1 0.02 WPV, m/sec** 9±1.3 6.4±1 4.7±1.5 0.01 CI, l/m2* 2.7±0.4 3.1±0.4 3.4±0.6 0.01 IC, l/m2** 2.4±0.6 2.6±0.3 3.2±0.6 0.01 SVRPI, dyn sec·cm* 1894±151 1783±454 1431±252 0.01 SVRPI, dyn sec·sec** 1900±436 1657±436 1385±248 0.01 Data are given as median and SD. *Measurements at week 22 of gestation. **Measurements at 1 year after delivery.

Conclusion

Preeclampsia showed different CVF compare with normotensive, before diagnosis and after delivery. The early endothelial dysfunction could be responsible of these changes.

Changes in body composition during and after adjuvant or neo-adjuvant chemotherapy in women with breast cancer stage I-IIIB compared with changes over a similar timeframe in women without cancer

Purpose

Body weight and body composition may change during and after adjuvant or neo-adjuvant chemotherapy for breast cancer. However, most studies did not include a comparison group of women without cancer, thus could not assess whether observed changes differed from age-related fluctuations in body weight and body composition over time. We assessed changes in body composition during and after chemotherapy in breast cancer patients compared with age-matched women not diagnosed with cancer.

Methods

We recruited 181 patients with stage I–IIIb breast cancer and 180 women without cancer. In patients, we assessed body composition using a dual-energy X-ray scan before start of chemotherapy (T1), shortly after chemotherapy (T2), and 6 months after chemotherapy (T3); for the comparison group, the corresponding time points were recruitment (T1) and 6 (T2) and 12 (T3) months.

Results

Fifteen percent of patients and 8% of the comparison group gained at least 5% in body weight between T1 and T3. Among the comparison group, no statistically significant changes in body weight, or body composition were observed over time. Body weight of patients significantly increased from baseline (72.1 kg ± 0.4 kg) to T2 (73.3 kg ± 0.4 kg), but decreased to 73.0 kg ± 0.4 kg after chemotherapy (T3). Lean mass of patients significantly increased from 43.1 kg ± 0.5 kg at baseline to 44.0 kg ± 0.5 kg at T2, but returned to 43.1 kg ± 0.5 kg at T3. There were no differential changes in fat mass over time between patients and the comparison group.

Conclusions

Changes in body weight and body composition during and after chemotherapy for early stage breast cancer were modest, and did not differ substantially from changes in body weight and body composition among women without cancer.

Non-linear registration improves statistical power to detect hippocampal atrophy in aging and dementia

OBJECTIVE

To compare the performance of different methods for determining hippocampal atrophy rates using longitudinal MRI scans in aging and Alzheimer's disease (AD).

BACKGROUND

Quantifying hippocampal atrophy caused by neurodegenerative diseases is important to follow the course of the disease. In dementia, the efficacy of new therapies can be partially assessed by measuring their effect on hippocampal atrophy. In radiotherapy, the quantification of radiation-induced hippocampal volume loss is of interest to quantify radiation damage. We evaluated plausibility, reproducibility and sensitivity of eight commonly used methods to determine hippocampal atrophy rates using test-retest scans.

MATERIALS AND METHODS

Manual, FSL-FIRST, FreeSurfer, multi-atlas segmentation (MALF) and non-linear registration methods (Elastix, NiftyReg, ANTs and MIRTK) were used to determine hippocampal atrophy rates on longitudinal T1-weighted MRI from the ADNI database. Appropriate parameters for the non-linear registration methods were determined using a small training dataset (N = 16) in which two-year hippocampal atrophy was measured using test-retest scans of 8 subjects with low and 8 subjects with high atrophy rates. On a larger dataset of 20 controls, 40 mild cognitive impairment (MCI) and 20  AD patients, one-year hippocampal atrophy rates were measured. A repeated measures ANOVA analysis was performed to determine differences between controls, MCI and AD patients. For each method we calculated effect sizes and the required sample sizes to detect one-year volume change between controls and MCI (NCTRL_MCI) and between controls and AD (NCTRL_AD). Finally, reproducibility of hippocampal atrophy rates was assessed using within-session rescans and expressed as an average distance measure DAve, which expresses the difference in atrophy rate, averaged over all subjects. The same DAve was used to determine the agreement between different methods.

RESULTS

Except for MALF, all methods detected a significant group difference between CTRL and AD, but none could find a significant difference between the CTRL and MCI. FreeSurfer and MIRTK required the lowest sample sizes (FreeSurfer: NCTRL_MCI = 115, NCTRL_AD = 17 with DAve = 3.26%; MIRTK: NCTRL_MCI = 97, NCTRL_AD = 11 with DAve = 3.76%), while ANTs was most reproducible (NCTRL_MCI = 162, NCTRL_AD = 37 with DAve = 1.06%), followed by Elastix (NCTRL_MCI = 226, NCTRL_AD = 15 with DAve = 1.78%) and NiftyReg (NCTRL_MCI = 193, NCTRL_AD = 14 with DAve = 2.11%). Manually measured hippocampal atrophy rates required largest sample sizes to detect volume change and were poorly reproduced (NCTRL_MCI = 452, NCTRL_AD = 87 with DAve = 12.39%). Atrophy rates of non-linear registration methods also agreed best with each other.

DISCUSSION AND CONCLUSION

Non-linear registration methods were most consistent in determining hippocampal atrophy and because of their better reproducibility, methods, such as ANTs, Elastix and NiftyReg, are preferred for determining hippocampal atrophy rates on longitudinal MRI. Since performances of non-linear registration methods are well comparable, the preferred method would mostly depend on computational efficiency.

Assessing a single SNP located at TERT/CLPTM1L multi-cancer risk region as a genetic modifier for risk of pancreatic cancer and melanoma in Dutch CDKN2A mutation carriers

Carriers of pathogenic variants in CDKN2A have a 70% life-time risk of developing melanoma and 15–20% risk of developing pancreatic cancer (PC). In the Netherlands, a 19-bp deletion in exon 2 of CDKN2A (p16-Leiden mutation) accounts for most hereditary melanoma cases. Clinical experience suggests variability in occurrence of melanoma and PC in p16-Leiden families. Thereby, the risk of developing cancer could be modified by both environmental and genetic contributors, suggesting that identification of genetic modifiers could improve patients’ surveillance. In a recent genome-wide association study (GWAS), rs36115365-C was found to significantly modify risk of PC and melanoma in the European population. This SNP is located on chr5p15.33 and has allele-specific regulatory activities on TERT expression. Herein, we investigated the modifying capacities of rs36115365-C on PC and melanoma in a cohort of 283 p16-Leiden carriers including 29 diagnosed with PC, 171 diagnosed with melanoma, 21 diagnosed with both PC and melanoma and 62 with neither PC nor melanoma. In contrast to previously reported findings, we did not find a significant association of PC risk with risk variant presence as determined by Generalized Estimating Equations (GEE) modelling. Interestingly, carrier-ship of the risk variant had a significant protective effect for melanoma (OR − 0.703 [95% CI − 1.201 to − 0.205], p = 0.006); however, the observed association was no longer significant after exclusion of probands to assess possible influence of ascertainment. Collectively, genetic modifiers for the prediction of PC and melanoma risk in p16-Leiden carriers remain to be determined.

Adherence to pre-set benchmark quality criteria to qualify as expert assessor of dysplasia in Barrett's esophagus biopsies - towards digital review of Barrett's esophagus

Background

Dysplasia assessment of Barrett’s esophagus biopsies is associated with low observer agreement; guidelines advise expert review. We have developed a web-based review panel for dysplastic Barrett’s esophagus biopsies.

Objective

The purpose of this study was to test if 10 gastrointestinal pathologists working at Dutch Barrett’s esophagus expert centres met pre-set benchmark scores for quality criteria.

Methods

Ten gastrointestinal pathologists twice assessed 60 digitalized Barrett’s esophagus cases, enriched for dysplasia; then randomised (7520 assessments). We tested predefined benchmark quality criteria: (a) percentage of ‘indefinite for dysplasia’ diagnoses, benchmark score ≤14% for all cases, ≤16% for dysplastic subset, (b) intra-observer agreement; benchmark score ≥0.66/≥0.39, (c) percentage agreement with ‘gold standard diagnosis’; benchmark score ≥82%/≥73%, (d) proportion of cases with high-grade dysplasia underdiagnosed as non-dysplastic Barrett’s esophagus; benchmark score ≤1/78 (≤1.28%) assessments for dysplastic subset.

Results

Gastrointestinal pathologists had seven years’ Barrett’s esophagus-experience, handling seven Barrett’s esophagus-cases weekly. Three met stringent benchmark scores; all cases and dysplastic subset, three met extended benchmark scores. Four pathologists lacked one quality criterion to meet benchmark scores.

Conclusion

Predefined benchmark scores for expert assessment of Barrett’s esophagus dysplasia biopsies are stringent and met by some gastrointestinal pathologists. The majority of assessors however, only showed limited deviation from benchmark scores. We expect further training with group discussions will lead to adherence of all participating gastrointestinal pathologists to quality criteria, and therefore eligible to join the review panel.

Inter-rater agreement in glioma segmentations on longitudinal MRI

Background

Tumor segmentation of glioma on MRI is a technique to monitor, quantify and report disease progression. Manual MRI segmentation is the gold standard but very labor intensive. At present the quality of this gold standard is not known for different stages of the disease, and prior work has mainly focused on treatment-naive glioblastoma. In this paper we studied the inter-rater agreement of manual MRI segmentation of glioblastoma and WHO grade II-III glioma for novices and experts at three stages of disease. We also studied the impact of inter-observer variation on extent of resection and growth rate.

Methods

In 20 patients with WHO grade IV glioblastoma and 20 patients with WHO grade II-III glioma (defined as non-glioblastoma) both the enhancing and non-enhancing tumor elements were segmented on MRI, using specialized software, by four novices and four experts before surgery, after surgery and at time of tumor progression. We used the generalized conformity index (GCI) and the intra-class correlation coefficient (ICC) of tumor volume as main outcome measures for inter-rater agreement.

Results

For glioblastoma, segmentations by experts and novices were comparable. The inter-rater agreement of enhancing tumor elements was excellent before surgery (GCI 0.79, ICC 0.99) poor after surgery (GCI 0.32, ICC 0.92), and good at progression (GCI 0.65, ICC 0.91). For non-glioblastoma, the inter-rater agreement was generally higher between experts than between novices. The inter-rater agreement was excellent between experts before surgery (GCI 0.77, ICC 0.92), was reasonable after surgery (GCI 0.48, ICC 0.84), and good at progression (GCI 0.60, ICC 0.80). The inter-rater agreement was good between novices before surgery (GCI 0.66, ICC 0.73), was poor after surgery (GCI 0.33, ICC 0.55), and poor at progression (GCI 0.36, ICC 0.73). Further analysis showed that the lower inter-rater agreement of segmentation on postoperative MRI could only partly be explained by the smaller volumes and fragmentation of residual tumor. The median interquartile range of extent of resection between raters was 8.3% and of growth rate was 0.22 mm/year.

Conclusion

Manual tumor segmentations on MRI have reasonable agreement for use in spatial and volumetric analysis. Agreement in spatial overlap is of concern with segmentation after surgery for glioblastoma and with segmentation of non-glioblastoma by non-experts.

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Inter-rater agreement for longitudinal glioma segmentation was determined.

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Agreement between 4 experts was higher than between 4 novices.

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Three time-points of glioblastoma (WHO IV) and diffuse glioma (WHO II-III) are studied.

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Impact on extent of resection and growth rate measurements was determined.

Temporal case study of household behavioural response to Cape Town's "Day Zero" using smart meter data

Faced with the threat of "Day Zero", when it was feared that Cape Town's taps could run dry, consumers reduced household water usage from 540 to 280 L per household per day over the 36 months between January 2015 and January 2018. This paper describes the events that prompted this reduction. We look at how changes in water use were affected by official announcements and by public engagement with this news via the social media activity and internet searches. We analysed the water usage of a subset of middle to high income households where smart hot and cold water meters were installed. For hot water usage patterns we compared meter readings with that in another area unaffected by the drought. We further map our cold water smart meter readings against that of the City of Cape Town's municipal data for domestic freestanding households - a sample of more than 400,000 households. We found that the introduction of Level 5 restrictions had a perverse effect on consumption, possibly due to confusing messages. The most dramatic change in behaviour appears to have been instigated by a media storm and consequent user panic after the release of the City's Critical Water Shortages Disaster Plan in October 2017. However, contradictory communication from national and provincial government eroded some of this gain. The paper concludes with recommendations for demand management in a similar future scenario.

Abstract B094: Successful identification of neoantigen-specific T-cell responses in low mutation burden colorectal cancers for personalized cancer vaccine development

Innovative treatment options are required to improve cure rates in advanced colorectal cancer patients. Immune checkpoint blockade therapy (anti-PD-1) was shown to be effective in colorectal cancers with high mutation burden (e.g., mismatch repair deficient) as antitumor reactivity is largely explained by the recognition of somatically mutated antigens (neoantigens). No immunotherapeutic strategies are currently available for patients diagnosed with low mutation burden colorectal cancer. We hypothesized that if neoantigen-reactive T-cells are present in low mutation burden patients, the latter could benefit from immunotherapeutic interventions that stimulate neoantigen recognition and the onset of a robust antitumor immune response.In order to detect neoantigens, whole exome and RNA next-generation sequencing analyses were performed in cancer and healthy tissues from five colorectal cancer patients. Corresponding neoepitopes were synthesized and tested for their ability to induce immune cell activation in T-cells isolated from the tumor tissue (TIL) and from peripheral blood. Neoantigen-specific T-cell responses were identified in the majority of patients that presented with tumors carrying 25 to 36 transcribed, non-synonymous variants. Up to six different neoantigens were recognized per tumor, which resulted in a higher detection rate than anticipated based on published data. Moreover, we discovered the merits of isolating CD39+CD103+CD8+ T-cells for detection of a broad recognition of HLA class I-restricted neoantigens. This CD39+CD103+CD8+ T-cell subset comprises the majority and a broader repertoire of neoantigen-specific T-cells compared to bulk TIL populations or lymphocytes derived from peripheral blood. In conclusion, we developed a neoantigen screening pipeline to unlock the immunogenic potential of colorectal cancers with low mutation burden. We have detected a relatively high number of neoantigens that are recognized by tumor- and/or PBMC-derived T-cells in mismatch repair proficient, low mutation burden colorectal cancer patients, and show the importance of the CD39+CD103+CD8+ T-cell subset for neoantigen-based immunotherapies. These findings warrant the further exploration of the potential to employ neoantigen-targeted therapies to improve clinical outcomes of colorectal cancer patients.

Citation Format: Jitske van den Bulk, Dina Ruano, Marieke E. Ijsselsteijn, Marten Visser, Ruud van der Breggen, Koen C.M.J. Peeters, Thomas Duhen, Rebekka Duhen, Andrew D Weinberg, Sjoerd S.H. van der Burg, Els M.E. Verdegaal, Noel F. de Miranda. Successful identification of neoantigen-specific T-cell responses in low mutation burden colorectal cancers for personalized cancer vaccine development [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B094.