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.

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.

IKZF1 alterations are not associated with outcome in 498 adults with B-precursor ALL enrolled in the UKALL14 trial.

IKZF1 deletions (ΔIKZF1) are commonly detected in B-precursor acute lymphoblastic leukemia (ALL; B-ALL) and are widely assumed to have a significant impact on outcome. We compared the ability of multiplex ligand-dependent probe amplification (MLPA) and polymerase chain reaction (PCR) to detect ΔIKZF1 and to determine the impact on event-free survival of patients with precursor B-ALL aged 23 to 65 years recruited to the completed trial UKALL14 (ISRCTN 66541317). From 655 recruits with BCR-ABL1+ and BCR-ABL1- B-ALL, all available diagnostic DNA samples (76% of the recruited population) were screened by multiplex end point PCR covering 4 deletions: dominant-negative (DN) Δ4-7 or the loss of function Δ2-7, Δ4-8, and Δ2-8 (n = 498), MLPA (n = 436), or by both (n = 420). Although patients with BCR-ABL1- ΔIKZF1 were more likely to have minimal residual disease at the end of induction, we did not find any impact of ΔIKZF1 (including subgroup analysis for DN or loss-of-function lesions) or the IKZF1plus genotype on event-free, overall survival, or relapse risk by univariable or multivariable analyses. Consistent with the technical approach, MLPA not only detected a wider range of deletions than PCR but also failed to detect some PCR-detected lesions. The main difference between our study and others reporting an association between ΔIKZF1 and outcome is the older age of participants in our population. The impact of ΔIKZF1 in ALL may be less marked in an older population of patients. Our study underscores the need for analyses in large, harmonized data sets. This trial was registered at www.clinicaltrials.gov as #NCT01085617.

Analysis of T and NK cell subsets in the 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 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 natural killer (NK) cells in a subcohort of donors. We compared these results with the immunophenotype of the oldest living Italian supercentenarian (aged 111 years). 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 being 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 cytomegalovirus (CMV) infection. The supercentenarian showed a unique immunophenotypic signature regarding the relative percentages of her T cell subsets, with CD4+ and CD8+ T cell percentages and CD4+ naive T cell values in line with those recorded for the octogenarian subjects. This suggests that the supercentenarian has a naive 'younger' T cell profile comparable to that of a >80-year-old female.

Triggering of Toll-like Receptors in Old Individuals. Relevance for Vaccination.

Aging is characterized by a general decline in a range of physiological functions, with a consequent increase in the risk of developing a variety of chronic diseases and geriatric syndromes. Additionally, increasing age is accompanied by a progressive decline in both innate and acquired immune system, referred to as immunosenescence. This impaired ability to mount an efficient immune response after exposure to microorganisms or vaccines represents a major challenge in acquiring protection against pathogens in aging. Therefore, there is still a great need for vaccines that are tailored to optimally stimulate the aged immune system, thus promoting more successful aging. Various strategies can be used to improve vaccine efficacy in old people. Despite this, metaanalyses have clearly shown that the magnitude of protection obtained remains lower in older adults. Recent studies show that stimulation of Toll-like receptors, using stimulatory ligands, can enhance vaccine efficacy by a number of mechanisms, including the activation of innate immune cells and the consequent production of inflammatory cytokines. Therefore, a possible strategy for more effective vaccination in the older population is the triggering of multiple TLRs, using a combined adjuvant for the synergistic activation of cellular immunity. Preliminary in vitro data suggest that in humans the presence of multiple TLR agonists can result in the greater stimulation of antigen-specific immune responses in immune cells both in the young healthy and in the immune senescent older donors. These data suggest that appropriately selected combinations of TLR agonists could enhance the efficacy of vaccination mediated immunity in older people.

Immunosenescence and Its Hallmarks: How to Oppose Aging Strategically? A Review of Potential Options for Therapeutic Intervention.

Aging is accompanied by remodeling of the immune system. With time, this leads to a decline in immune efficacy, resulting in increased vulnerability to infectious diseases, diminished responses to vaccination, and a susceptibility to age-related inflammatory diseases. An age-associated immune alteration, extensively reported in previous studies, is the reduction in the number of peripheral blood naïve cells, with a relative increase in the frequency of memory cells. These two alterations, together with inflamm-aging, are considered the hallmarks of immunosenescence. Because aging is a plastic process, it is influenced by both nutritional and pharmacological interventions. Therefore, the role of nutrition and of immunomodulation in immunosenescence is discussed, due to the multifactorial influence on these hallmarks. The close connection between nutrition, intake of bioactive nutrients and supplements, immune function, and inflammation demonstrate the key role of dietary strategies as regulators of immune response and inflammatory status, hence as possible modulators of the rate of immunosenescence. In addition, potential options for therapeutic intervention are clarified. In particular, the use of interleukin-7 as growth factor for naïve T cells, the function of checkpoint inhibitors in improving T cell responses during aging and, the potential of drugs that inhibit mitogen-activated protein kinases and their interaction with nutrient signaling pathways are discussed. Finally, it is suggested that the inclusion of appropriate combinations of toll-like receptor agonists may enhance the efficacy of vaccination in older adults.

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

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.

Mouse xenograft modeling of human adult acute lymphoblastic leukemia provides mechanistic insights into adult LIC biology.

The distinct nature of acute lymphoblastic leukemia (ALL) in adults, evidenced by inferior treatment outcome and different genetic landscape, mandates specific studies of disease-initiating mechanisms. In this study, we used NOD/LtSz-scid IL2Rγ null(c) (NSG) mouse xenotransplantation approaches to elucidate leukemia-initiating cell (LIC) biology in primary adult precursor B (pre-B) ALL to optimize disease modeling. In contrast with xenografting studies of pediatric ALL, we found that modification of the NSG host environment using preconditioning total body irradiation (TBI) was indispensable for efficient engraftment of adult non-t(4;11) pre-B ALL, whereas t(4;11) pre-B ALL was successfully reconstituted without this adaptation. Furthermore, TBI-based xenotransplantation of non-t(4;11) pre-B ALL enabled detection of a high frequency of LICs (<1:6900) and permitted frank leukemic engraftment from a remission sample containing drug-resistant minimal residual disease. Investigation of TBI-sensitive stromal-derived factor-1/chemokine receptor type 4 signaling revealed greater functional dependence of non-t(4;11) pre-B ALL on this niche-based interaction, providing a possible basis for the differential engraftment behavior. Thus, our studies establish the optimal conditions for experimental modeling of human adult pre-B ALL and demonstrate the critical protumorogenic role of microenvironment-derived SDF-1 in regulating adult pre-B LIC activity that may present a therapeutic opportunity.