DNA damage signalling from the placenta to foetal blood as a potential mechanism for childhood leukaemia initiation

Abstract For many diseases with a foetal origin, the cause for the disease initiation remains unknown. Common childhood acute leukaemia is thought to be caused by two hits, the first in utero and the second in childhood in response to infection. The mechanism for the initial DNA damaging event are unknown. Here we have used in vitro, ex vivo and in vivo models to show that a placental barrier will respond to agents that are suspected of initiating childhood leukaemia by releasing factors that cause DNA damage in cord blood and bone marrow cells, including stem cells. We show that DNA damage caused by in utero exposure can reappear postnatally after an immune challenge. Furthermore, both foetal and postnatal DNA damage are prevented by prenatal exposure of the placenta to a mitochondrially-targeted antioxidant. We conclude that the placenta might contribute to the first hit towards leukaemia initiation by bystander-like signalling to foetal haematopoietic cells

Analysis of T and NK cell subsets in Sicilian population from young to supercentenarian: the role of age and gender

Ageing dramatically affects number and function of both innate and adaptive arms of immune system, particularly T cell subsets, contributing to reduced vaccination efficacy, decreased resistance to infections and increased prevalence of cancer in the older people. In the present paper, we analysed the age-related changes in the absolute number of lymphocytes in 214 Sicilian subjects, and in the percentages of T and NK cells in a sub-cohort of donors. We compared these results with the immunophenotype of the oldest living Italian supercentenarian (111 years old). The results were also sorted by gender. The correlation between number/percentage of cells and age in all individuals and, separately, in males and females, was examined using a simple linear regression analysis. We did not record the increase in the rate of inversion of the CD4/CD8 ratio frequently reported as associated with ageing in literature. Our observation was the direct consequence of a flat average trend of CD4+ and CD8+ T cell percentages in ageing donors, even when gender differences were included. Our results also suggest that CD4+ and CD8+ subsets are not affected equally by age comparing females with males, and we speculated that gender may affect the response to CMV infection. The supercentenarian showed a unique immunophenotypic signature as regards the relative percentages of her T cell subsets, with CD4+ and CD8+ T cell percentages and CD4+ na\uefve T cell values in line with those recorded for the octogenarian subjects. This suggests that the supercentenarian has a na\uefve "younger" T cell profile comparable to that of a >80 year old female

A Phase 1 trial of human telomerase reverse transcriptase (hTERT) vaccination combined with therapeutic strategies to control immune-suppressor mechanisms

The presence of inhibitory immune cells and difficulty in generating activated effector T-cells remain obstacles to development of effective cancer vaccines. We designed a vaccine regimen combining human telomerase reverse transcriptase (hTERT) peptides with concomitant therapies targeting regulatory T-cells (Tregs) and cyclooxygenase-2 (COX2)-mediated immunosuppression. This Phase 1 trial combined an hTERT-derived 7-peptide library, selected to ensure presentation by both HLA class-I and class-II in 90% of patients, with oral low-dose cyclophosphamide (to modulate Tregs) and the COX2 inhibitor celecoxib. Adjuvants were Montanide and topical TLR-7 agonist, to optimise antigen presentation. The primary objective was determination of the safety and tolerability of this combination therapy, with anti-cancer activity, immune response and detection of antigen-specific T-cells as additional endpoints. Twenty-nine patients with advanced solid tumours were treated. All were multiply-pretreated, and the majority had either colorectal or prostate cancer. The most common adverse events were injection-site reactions, fatigue and nausea. Median progression-free survival was 9 weeks, with no complete or partial responses, but 24% remained progression-free for ≥6 months. Immunophenotyping showed post-vaccination expansion of CD4+ and CD8+ T-cells with effector phenotypes. The in vitro re-challenge of T-cells with hTERT peptides, TCR sequencing, and TCR similarity index analysis demonstrated the expansion following vaccination of oligoclonal T-cells with specificity for hTERT. However, a population of exhausted PD-1 + cytotoxic T-cells was also expanded in vaccinated patients. This vaccine combination regimen was safe and associated with antigen-specific immunological responses. Clinical activity could be improved in future by combination with anti-PD1 checkpoint inhibition to address the emergence of an exhausted T-cell population

Dissecting the role of cooperating genetic lesions in acute leukaemia

My thesis investigates cytogenetics and molecular genetics of acute leukaemia. In the cytogenetics part, I aimed to map and characterize recurrently altered regions of the RUNX1 and TET2 genes in myeloid malignancies by fluorescence in situ hybridization (FISH) technique using gene specific in house designed fosmid/BAC probes, and to investigate whether this FISH technique could confirm the presence of cryptic genome lesions that were previously identified by aCGH screening. I developed a sensitive FISH method that confirmed these genome imbalances in all cases with a variety of sizes comparable to aCGH. Consequently the strategy I propose for therapy response monitoring in myeloid malignancies starts with FISH analysis by addressing a selected abnormality depending on patient’s history. In cases where FISH provides evidence for persistent disease, aCGH is recommended to assess the level of genome complexity and evolution of the size of genome loss. Second part of this thesis investigates molecular genetics of acute lymphoblastic leukaemia (ALL). Deletion in the IKZF1 gene is common and prognostic of poor outcome. I aimed to assess the utility of the IKZF1 exons 4-7 deletion (IKZF1 Δ4-7) as a minimal residual disease (MRD) marker in adult BCR-ABL1-negative ALL and to investigate the contexts and mechanisms by which IKZF1 Δ4-7 encoded protein, IK6, contributes to enhanced leukaemogenesis. I showed that IKZF1 Δ4-7 was typically subclonal and instable during the course of disease, signifying that the positive suggestion of IKZF1 Δ4-7 as an MRD marker is not encouraging. Overexpression of IK6 appeared to play a role in higher growth rate, drug resistance and increased DNA instability and this role may be more pronounced in the presence of BCR-ABL1. By contrast, the poor risk phenotype conferred by IK6 expression in BCR-ABL1-negative ALL cannot be elucidated further by this dataset suggesting that alternative co-operating lesions are in action

A phase 1 trial of human telomerase reverse transcriptase (hTERT) vaccination combined with therapeutic strategies to control immune-suppressor mechanisms

The presence of inhibitory immune cells and difficulty in generating activated effector T cells remain obstacles to development of effective cancer vaccines. We designed a vaccine regimen combining human telomerase reverse transcriptase (hTERT) peptides with concomitant therapies targeting regulatory T cells (Tregs) and cyclooxygenase-2 (COX2)-mediated immunosuppression. This Phase 1 trial combined an hTERT-derived 7-peptide library, selected to ensure presentation by both HLA class-I and class-II in 90% of patients, with oral low-dose cyclophosphamide (to modulate Tregs) and the COX2 inhibitor celecoxib. Adjuvants were Montanide and topical TLR-7 agonist, to optimise antigen presentation. The primary objective was determination of the safety and tolerability of this combination therapy, with anti-cancer activity, immune response and detection of antigen-specific T cells as additional endpoints. Twenty-nine patients with advanced solid tumours were treated. All were multiply-pretreated, and the majority had either colorectal or prostate cancer. The most common adverse events were injection-site reactions, fatigue and nausea. Median progression-free survival was 9 weeks, with no complete or partial responses, but 24% remained progression-free for ≥6 months. Immunophenotyping showed post-vaccination expansion of CD4+ and CD8+ T cells with effector phenotypes. The in vitro re-challenge of T cells with hTERT peptides, TCR sequencing, and TCR similarity index analysis demonstrated the expansion following vaccination of oligoclonal T cells with specificity for hTERT. However, a population of exhausted PD-1+ cytotoxic T cells was also expanded in vaccinated patients. This vaccine combination regimen was safe and associated with antigen-specific immunological responses. Clinical activity could be improved in future by combination with anti-PD1 checkpoint inhibition to address the emergence of an exhausted T cell population.</jats:p

How Can We Improve the Vaccination Response in Older People? Part II: Targeting Immunosenescence of Adaptive Immunity Cells

The number of people that are 65 years old or older has been increasing due to the improvement in medicine and public health. However, this trend is not accompanied by an increase in quality of life, and this population is vulnerable to most illnesses, especially to infectious diseases. Vaccination is the best strategy to prevent this fact, but older people present a less efficient response, as their immune system is weaker due mainly to a phenomenon known as immunosenescence. The adaptive immune system is constituted by two types of lymphocytes, T and B cells, and the function and fitness of these cell populations are affected during ageing. Here, we review the impact of ageing on T and B cells and discuss the approaches that have been described or proposed to modulate and reverse the decline of the ageing adaptive immune system

How Can We Improve Vaccination Response in Old People? Part I: Targeting Immunosenescence of Innate Immunity Cells

Vaccination, being able to prevent millions of cases of infectious diseases around the world every year, is the most effective medical intervention ever introduced. However, immunosenescence makes vaccines less effective in providing protection to older people. Although most studies explain that this is mainly due to the immunosenescence of T and B cells, the immunosenescence of innate immunity can also be a significant contributing factor. Alterations in function, number, subset, and distribution of blood neutrophils, monocytes, and natural killer and dendritic cells are detected in aging, thus potentially reducing the efficacy of vaccines in older individuals. In this paper, we focus on the immunosenescence of the innate blood immune cells. We discuss possible strategies to counteract the immunosenescence of innate immunity in order to improve the response to vaccination. In particular, we focus on advances in understanding the role and the development of new adjuvants, such as TLR agonists, considered a promising strategy to increase vaccination efficiency in older individuals