Michaela Hassler

Sex-Specific Prevalence of Adenomas, Advanced Adenomas, and Colorectal Cancer in Individuals Undergoing Screening Colonoscopy

CONTEXT Although some studies have shown that men are at greater age-specific risk for advanced colorectal neoplasia than women, the age for referring patients to screening colonoscopy is independent of sex and usually recommended to be 50 years. OBJECTIVE To determine and compare the prevalence and number needed to screen (NNS) for adenomas, advanced adenomas (AAs), and colorectal carcinomas (CRCs) for different age groups in men and women. DESIGN, SETTING, AND PATIENTS Cohort study of 44,350 participants in a national screening colonoscopy program over a 4-year period (2007 to 2010) in Austria. MAIN OUTCOME MEASURES Prevalence and NNS of adenomas, AAs, and CRCs in different age groups for men and women. RESULTS The median ages were 60.7 years (interquartile range [IQR], 54.5-67.5 years) for women and 60.6 years (IQR, 54.3-67.6 years) for men, and the sex ratio was nearly identical (51.0% [22,598] vs 49.0% [21,572]). Adenomas were found in 19.7% of individuals screened (95% CI, 19.3%-20.1%; n = 8743), AAs in 6.3% (95% CI, 6.1%-6.5%; n = 2781), and CRCs in 1.1% (95% CI, 1.0%-1.2%; n = 491); NNS were 5.1 (95% CI, 5.0-5.2), 15.9 (95% CI, 15.4-16.5), and 90.9 (95% CI, 83.3-100.0), respectively. Male sex was significantly associated with a higher prevalence of adenomas (24.9% [95% CI, 24.3%-25.4%] vs 14.8% [95% CI, 14.3%-15.2%]; P < .001; unadjusted odds ratio [OR], 1.9 [95% CI, 1.8-2.0]), AAs (8.0% [95% CI, 7.6%-8.3%] vs 4.7% [95% CI, 4.4%-4.9%]; P < .001; unadjusted OR, 1.8 [95% CI, 1.6-1.9]), and CRCs (1.5% [95% CI, 1.3%-1.7%] vs 0.7% [95% CI, 0.6%-0.9%]; P < .001; unadjusted OR, 2.1 [95% CI, 1.7-2.5]). The prevalence of AAs in 50- to 54-year-old individuals was 5.0% (95% CI, 4.4%-5.6%) in men but 2.9% (95% CI, 2.5%-3.4%) in women (adjusted P = .001); the NNS in men was 20 (95% CI, 17.8-22.6) vs 34 in women (95% CI, 29.1-40; adjusted P = .001). There was no statistical significance between the prevalence and NNS of AAs in men aged 45 to 49 years compared with women aged 55 to 59 years (3.8% [95% CI, 2.3%-6.1%] vs 3.9% [95% CI, 3.3%-4.5%] and 26.1 [95% CI, 16.5-44.4] vs 26 [95% CI, 22.5-30.2]; P = .99). CONCLUSION Among a cohort of Austrian individuals undergoing screening colonoscopy, the prevalence and NNS of AAs were comparable between men aged 45 to 49 years and women aged 55 to 59 years.

Preventive sublingual immunotherapy in preschool children: first evidence for safety and pro-tolerogenic effects.

Prevention of new IgE sensitizations has been described during allergen‐specific immunotherapy. However, prospective data using a preventive approach in very young children who would benefit most are missing. We initiated a prospective pilot study investigating the safety, immunomodulatory, and sensitization‐preventive effect of sublingual immunotherapy (SLIT) in mono/oligoclonally sensitized, clinically asymptomatic children 2–5 yr of age.

Cryopreservation of Monocytes Is Superior to Cryopreservation of Immature or Semi-mature Dendritic Cells for Dendritic Cell-based Immunotherapy

Cryopreservation of immature or mature dendritic cells (DC) has been proposed as a suitable method to gain large numbers of DC for immunotherapeutic trials against cancer. However, clinical studies using cryopreserved DC have demonstrated only limited success so far. The aim of this study was to investigate whether cryopreservation of monocytes elicits more potent DC and whether these DC are comparable to freshly generated DC preparations. Monocytes, either separated immunomagnetically or by means of leukapheresis and elutriation, were differentiated into DC and cryopreserved at various developmental stages. DC preparations were analyzed regarding recovery, viability, phenotype, and functional properties. In contrast to DC frozen at their immature or semi-mature state, generation of DC from cryopreserved monocytes elicited viability values comparable with freshly generated DC. Furthermore, using frozen monocytes for DC differentiation revealed improved expression of DC surface markers and interleukin-12p70 secretion as compared with DC generated from frozen immature or frozen semi-mature DC. Impaired phenotypical appearance of the latter DC variants was further substantiated by functional analysis. T-cells cocultured with these DC showed decreased expression of interferon-γ and granzyme B, and lowered proliferation when compared with T-cells cocultured with DC generated from frozen monocytes or DC generated from freshly isolated monocytes. Induction of regulatory T-cell populations was negligible among all investigated DC preparations. These findings may further improve DC-based immunotherapeutical protocols. Cryopreservation of unchallenged monocytes enables targeted therapy by loading DC with varying antigenic compositions in case of tumor escape during treatment.

Allogeneic tumor lysate can serve as both antigen source and protein supplementation for dendritic cell culture

BackgroundRecent preclinical and clinical evidence suggests the use of allogeneic tumor as a source of antigen for DC-based immunotherapy against cancer. We hypothesized that addition of allogeneic tumor lysate to monocyte-derived DC culture could serve a dual purpose: (1) antigen source and (2) protein supplementation of DC culture media. Protein supplementation whether of known origin (human serum/plasma, fetal bovine serum, human serum albumin) or undeclared origin (“serum-free” media) is a source of variability and bias. We addressed the question whether protein supplementation can be omitted in the presence of allogeneic tumor lysate.Materials and methodsHuman DC cultured in the presence of lysate from medullary thyroid carcinoma (MTC) cell line SHER-I (TuLy-DC) and DC pulsed with the same lysate but cultured in the presence of FBS (FBS-DC) were assessed for morphology, phenotype, maturation and functional properties.ResultsIn comparison of FBS-DC/TuLy-DC no significant differences in morphology, phenotype and maturation could be detected. Both culture conditions produced CD1ahigh, CD14low DC with high expression of costimulatory molecules and CD83 upon stimulation. TuLy-DC gave significantly better yields and produced more IL12p70. DC showed high (allo)stimulatory capacity toward T-cells. TuLy-DC induced more intracellular IFNγ in CD8+T-cells of vaccinated MTC patients. Both types of DC induced killing of SHER-I after short in vitro restimulation.Summary and conclusionTumor lysate from SHER-I can substitute for further protein supplementation in DC culture. Allogeneic tumor lysates should be taken into consideration as both source of antigen and protein supplementation in monocyte-derived DC culture.

Development of a personalized cellular ex-vivo cbl-b silencing cancer immunotherapy

Background The E3 ubiquitin ligase cbl-b has been identified as an important gatekeeper limiting T cell activation. Concordantly, the immune system of cbl-b deficient mice can effectively fight tumors, thereby validating cbl-b as an excellent target to enhance anti-tumor immune activity. We have recently shown in proof-of-concept experiments that transfer of transiently cbl-b silenced murine T cells had efficacy to enhance the anti-tumor immune response in mouse models. Methods A design algorithm was used to screen for siRNAs that are highly effective to silence cbl-b, and the optimized siRNA was produced at a GMP manufacturer. PBMCs were isolated from healthy donors or cancer patients, transfected with siRNA by electroporation and immune cell phenotype and activation was determined by FACS and ELISA. For enhancement of DC vaccination responses, PBMCs were ex vivo silenced, and co-administrated with the DC preparations intranodally to the cancer patient. Results We have established a highly efficient transfection protocol using a commercial electroporation device enabling us to simultaneously transfect T, B, NK cells and monocytes with minimal cell damage. Using this protocol, we have identified a siRNA that was able to shut down cbl-b expression for more than 7 days in stimulated human T cells, resulting in strong enhancement of T cell activation, cytokine production and proliferation. Moreover, simultaneous silencing of cbl-b in all immune cells of the PBMCs yielded additional advantages, most notably enhancing NK cell reactivity against tumor cell and IL-2 stimulation. Silencing of cancer patient PBMCs yielded similar results ex vivo and intranodal transfer of autologous cbl-b silenced cells together with activated DCs to patients with advanced cancers was feasible and well tolerated. Conclusions To enable the clinical implementation of a cbl-b ex vivo silencing treatment, we have established and tested a protocol that can be easily performed on any clinical unit that applies adoptive cell therapies to patients. Based on these results, a Phase I trial for the systemic administration of cbl-b silenced PBMCs to patients with advanced cancers is presently being set up.

Improvement of a dendritic cell-based tumour vaccine by an influenza virus.

Background  Induction of cytotoxic T cells by dendritic cells (DCs) is a promising approach to tumour‐immunotherapy. A standardized effective preparation of DCs remains a challenge for clinical application.

Treatment of a cancer patient by an adoptive cell therapy protocol combining DC vaccination with cbl-b ex vivo silencing

Meeting abstracts The E3 ubiquitin ligase cbl-b has been identified as a key intracellular checkpoint limiting T and NK cell activation. Concordantly, blockade of cbl-b function by genetic deletion strongly enhances anti-tumor immune responses, thereby validating cbl-b as target for immunotherapy.