Trained Immunity-Based Vaccine in B Cell Hematological Malignancies With Recurrent Infections: A New Therapeutic Approach

Trained immunity inducers in cancer immunotherapy

While most of the cancer immunotherapy strategies engage adaptive immunity, especially tumor-associated T cells, the small fraction of responding patients and types of cancers amenable, and the possibility of severe adverse effects limit its usage. More effective and general interventions are urgently needed. Recently, a de facto innate immune memory, termed 'trained immunity', has become a new research focal point, and promises to be a powerful tool for achieving long-term therapeutic benefits against cancers. Trained immunity-inducing agents such as BCG and fungal glucan have been shown to be able to avert the suppressive tumor microenvironment (TME), enhance T cell responses, and eventually lead to tumor regression. Here, we review the current understating of trained immunity induction and highlight the critical roles of emergency granulopoiesis, interferon γ and tissue-specific induction. Preclinical and clinical studies that have exploited trained immunity inducers for cancer immunotherapy are summarized, and repurposed trained immunity inducers from other fields are proposed. We also outline the challenges and opportunities for trained immunity in future cancer immunotherapies. We envisage that more effective cancer vaccines will combine the induction of trained immunity with T cell therapies.

Heat-killed Mycobacterium tuberculosis induces trained immunity in vitro and in vivo administered systemically or intranasally

Trained immunity (TI) represents a memory-like process of innate immune cells. TI can be initiated with various compounds such as fungal β-glucan or the tuberculosis vaccine, Bacillus Calmette-Guérin. Nevertheless, considering the clinical applications of harnessing TI against infections and cancer, there is a growing need for new, simple, and easy-to-use TI inducers. Here, we demonstrate that heat-killed Mycobacterium tuberculosis (HKMtb) induces TI both in vitro and in vivo. In human monocytes, this effect represents a truly trained process, as HKMtb confers boosted inflammatory responses against various heterologous challenges, such as lipopolysaccharide (Toll-like receptor [TLR] 4 ligand) and R848 (TLR7/8 ligand). Mechanistically, HKMtb-induced TI relies on epigenetic mechanisms in a Syk/HIF-1α-dependent manner. In vivo, HKMtb induced TI when administered both systemically and intranasally, with the latter generating a more robust TI response. Summarizing, our research has demonstrated that HKMtb has the potential to act as a mucosal immunotherapy that can successfully induce trained responses.

Do bacterial vaccines/adjuvants prevent wheezing episodes in children?

PURPOSE OF REVIEW

To discuss recently discovered mechanisms of action of some bacterial vaccines that may account for their clinical benefit in the prevention of recurrent wheezing and asthma exacerbations in infants and early childhood.

RECENT FINDINGS

Trained immunity has been shown to confer innate immune cells with a quite long-term nonspecific protection against a broad spectrum of pathogens. Inducers of trained immunity include some bacterial vaccines. Trained immunity-based vaccines (TIbV) of bacterial origin have the capability to induce nonspecific responses to a variety of pathogens, including respiratory viruses, in addition to their nominal bacterial antigens. Clinical data, from epidemiological surveys to well designed randomized clinical trials, indicate that TIbV formulated with bacteria prevent respiratory tract infections of viral cause, such as those associated with recurrent wheezing or asthma exacerbation, in children. Administration of these vaccines by the mucosal route may be important for their outcome in respiratory infections.

SUMMARY

Mucosal bacterial immunotherapy, including certain TIbV, confer protection against a broad spectrum of pathogens, such as viruses, through a mechanism mediated by trained immunity. Clinical studies on the use of these preparations against recurrent wheezing reflect these mechanistic effects. These findings open a new avenue for the development of new strategies for this condition.

Association of Procalcitonin with the Patient’s Infection Characteristics and Prognosis after Hematopoietic Stem Cell Transplantation

Objective

To study whether procalcitonin (PCT) is an important indicator of infection with or without agranulocytosis and to reveal whether PCT can distinguish between infected sites and affect prognosis after hematopoietic stem cell transplantation (HSCT).

Method

In the present study, 682 patients with HSCT were enrolled, and their clinical characteristics were noted. Their blood culture and inflammatory and biochemical indicators were studied. The patients were divided into respective groups according to the degree of agranulocytosis, type of bacterial infection, infected sites, and prognosis.

Results

The PCT, CRP, and D-dimer levels were significantly improved in patients with positive blood culture results compared to the case for those with negative blood culture results. The PCT level was the highest in the gram-negative group. The levels of PCT and D-dimer were significantly elevated in patients with infection and agranulocytosis after HSCT compared to those in the nonagranulocytosis cohort. Interestingly, no significant difference in the PCT level was observed among any of the eight foci. Lower PCT levels were associated with higher survival in patients with infection after HSCT.

Conclusion

Among patients that underwent HSCT, PCT levels were significantly elevated in those with infection and agranulocytosis, with the levels being specifically high in the gram-negative group. Moreover, lower PCT levels were associated with higher survival in patients with infection after HSCT.

Combined Immune Defect in B-Cell Lymphoproliferative Disorders Is Associated with Severe Infection and Cancer Progression

B cell chronic lymphoproliferative diseases (B-CLPD) are associated with secondary antibody deficiency and other innate and adaptive immune defects, whose impact on infectious risk has not been systematically addressed. We performed an immunological analysis of a cohort of 83 B-CLPD patients with recurrent and/or severe infections to ascertain the clinical relevance of the immune deficiency expression. B-cell defects were present in all patients. Patients with combined immune defect had a 3.69-fold higher risk for severe infection (p = 0.001) than those with predominantly antibody defect. Interestingly, by Kaplan–Meier analysis, combined immune defect showed an earlier progression of cancer with a hazard ratio of 3.21, than predominantly antibody defect (p = 0.005). When B-CLPD were classified in low-degree, high-degree, and plasma cell dyscrasias, risk of severe disease and cancer progression significantly diverged in combined immune defect, compared with predominantly antibody defect (p = 0.001). Remarkably, an underlying primary immunodeficiency (PID) was suspected in 12 patients (14%), due to prior history of infections, autoimmune and granulomatous conditions, atypical or variegated course and compatible biological data. This first proposed SID classification might have relevant clinical implications, in terms of predicting severe infections and cancer progression, and might be applied to different B-CLPD entities.

New drugs under development for COPD

The characteristic features of chronic obstructive pulmonary disease (COPD) include inflammation and remodelling of the lower airways and lung parenchyma together with activation of inflammatory and immune processes. Due to the increasing habit of cigarette smoking worldwide COPD prevalence is increasing globally. Current therapies are unable to prevent COPD progression in many patients or target many of its hallmark characteristics which may reflect the lack of adequate biomarkers to detect the heterogeneous clinical and molecular nature of COPD. In this chapter we review recent molecular data that may indicate novel pathways that underpin COPD subphenotypes and indicate potential improvements in the classes of drugs currently used to treat COPD. We also highlight the evidence for new drugs or approaches to treat COPD identified using molecular and other approaches including kinase inhibitors, cytokine- and chemokine-directed biologicals and small molecules, antioxidants and redox signalling pathway inhibitors, inhaled anti-infectious agents and senolytics. It is important to consider the phenotypes/molecular endotypes of COPD patients together with specific outcome measures to target new therapies to particular COPD subtypes. This will require greater understanding of COPD molecular pathologies and a focus on biomarkers of predicting disease subsets and responder/non-responder populations.

B-cell haematological malignancies and SARS-CoV-2 infection: Could immunological interventions influence the outcome?

B cell haematological malignancies (HMs) have been described as the worst cancer type for concomitant COVID-19 in terms of mortality, with rates up to 65%. This risk factor for COVID-19 cannot only be explained by comorbidities and advanced age of patients, but aggravated by secondary immunodeficiency (SID). We aimed at evaluating the impact of COVID-19 on 86 HM patients with concomitant SID from a single centre. Only 14 HM patients of 86 (16.28%) patients suffered COVID-19, with mortality rate of 7%. When we considered patients according to B-cell defect only or multiple immune defect overlap (B-T-cell/NK cells/complement), patients with immune defect overlap presented 5.30-fold higher risk of COVID-19 than only B cell defect (95% CI, 1.67-17.0) (p = 0.004). Seven (50%) patients were on active IgRT; while five (36%) had received prior mucosal vaccines for respiratory infections. Our results show that modelling SID in HM may contribute to better prediction of infectious risk and to prompt more targeted and timely preventive therapies.

Sublingual Bacterial Vaccination Reduces Recurrent Infections in Patients With Autoimmune Diseases Under Immunosuppressant Treatment

Introduction

Conventional or biologic disease-modifying anti-rheumatic drugs (DMARDs) are the mainstay of treatment for systemic autoimmune disease (SAD). Infectious complications are a major concern in their use.

Objective

To evaluate the clinical benefit of sublingual mucosal polybacterial vaccines (MV130 and MV140), used to prevent recurrent respiratory and urinary tract infections, in patients with SAD and secondary recurrent infections following conventional or biologic DMARDs.

Methods

An observational study in SAD patients with recurrent respiratory tract infections (RRTI) and/or recurrent urinary tract infections (RUTI) was carried out. All patients underwent mucosal (sublingual) vaccination with MV130 for RRTI or with MV140 for RUTI daily for 3 months. Clinical evaluation was assessed during 12 months of follow-up after the first dose, i.e., 3 months under treatment and 9 months once discontinued, and compared with the previous year.

Results

Forty-one out of 55 patients completed 1-year follow-up. All patients were on either conventional or biologic DMARDs. A significant decrease in the frequency of RUTI (p<0.001), lower respiratory tract infections (LRTI) (p=0.009) and upper respiratory tract infections (URTI) (p=0.006) at 12-mo with respect to the previous year was observed. Antibiotic prescriptions and unscheduled medical visits decreased significantly (p<0.020) in all groups. Hospitalization rate also declined in patients with RRTI (p=0.019). The clinical benefit demonstrated was concomitant to a significant increase in both anti-S. pneumoniae IgA and IgG antibodies following MV130 vaccination.

Conclusions

Sublingual polybacterial vaccines prevent recurrent infections in patients with SAD under treatment with immunosuppressant therapies, supporting a broad non-specific anti-infectious effect in these patients.