Quadrivalent Live-Attenuated Influenza Vaccine in Milan preschools: an Italian experience of school-located flu vaccination within the 2022-2023 season.

BACKGROUND: In Italy, since the 2020-2021 flu season, the flu vaccine recommendation was extended to all children aged 6 months to 6 years and quadrivalent Live-Attenuated Influenza Vaccine (qLAIV) was introduced. Since school-aged children are important carriers of annual influenza epidemics, a school-based influenza vaccination program may potentially increase vaccine uptake. Recent studies, conducted in the UK and the US, show that school-based vaccination can reach higher percentage of paediatric vaccination coverage compared to children vaccinated in other settings. METHODS: During 2022-2023 flu season in 9 preschools located in Milan healthcare personnel vaccinated children with qLAIV at the end of a school day. A Google Form questionnaire was administered to preschoolers' parents of all preschools within the Municipality of Milan. RESULTS: In the preschools engaged in the vaccination program, 233 out of 1939 children were vaccinated (12%). Among these, 61 (26.2%) had never been vaccinated for influenza before. Vaccination coverage was 11.5% for Italian children and 14.3% for children coming from an immigrant background. We collected 3659 questionnaire responses, divided according to study participation status (371 from preschools that participated in the vaccination program and 3288 from other preschools in Milan). 57% of the families who answered to the questionnaire vaccinated their children for flu. qLAIV accounted for 85.6% of vaccinations. We observed a statistically significant difference in the percentage of vaccinated children between those attending a school participating in the project (67.9%) and children attending other schools (56%) (p < 0.001). Vaccination was administered by family pediatricians (48.9%), in vaccination centers (34.8%), in vaccine hubs (11.3%), in schools (2.6%), by private pediatricians (1.6%) and in other settings (0.7%). Focusing on the responses from families whose children attend schools participating in the vaccination program, 21.8% stated that the vaccination was provided in school. CONCLUSION: According to our experience, in Italy, at the moment, only the cooperation between health providers and alternative settings, including schools, may expand flu vaccination coverage. In particular, schools are to be considered a place to inform and reach out to families, useful to increase vaccination coverage.

Preschool-located influenza vaccination and influenza-like illness surveillance: an Italian pilot experience.

BACKGROUND: We describe the first school-located influenza vaccination campaign with quadrivalent live-attenuated influenza vaccine (LAIV) among pre-school children in Italy, coupled with an innovative school-centred influenza-like illnesses (ILIs) surveillance using a self-sampling non-invasive saliva collection method. METHODS: The pilot study was proposed during the 2021/2022 influenza season to fifteen pre-schools in the Milan municipality. LAIV was offered directly in school to all healthy children without contraindications. ILI differential diagnosis was conducted by real-time RT-PCR for influenza A/B and SARS-CoV-2. RESULTS: Five pre-schools were involved in the pilot project and overall, 135 families (31.2%) participated in the study, adhering to both surveillance and vaccination; 59% of families had an immigrant background. No pupil experienced adverse reactions after vaccination. Nineteen saliva samples were collected from sixteen children (11.8%). Six samples (31.6%) tested positive for SARS-CoV-2; none was positive for influenza A/B. CONCLUSIONS: The participation in the immunisation campaign was good, considering possible absences due to COVID-19 pandemic, and the intranasal administration was well tolerated and helped to overcome parental hesitancy. Saliva sampling represented a useful tool to reduce children's stress and increase parents' compliance. The high participation of families with an immigrant background suggests that school-based interventions can represent an effective strategy to overcome socioeconomic and cultural barriers.

The impact of adiposity indices on lung function in children with respiratory allergic diseases.

INTRODUCTION: The effect of obesity on lung function in children stratified by asthma status is not fully elucidated. We evaluated the impact of adiposity indices, including Body Mass Index (BMI) and estimated fat mass (eFT), on lung changes in asthmatic and non-asthmatic children with rhinitis. PATIENTS AND METHODS: We performed a retrospective review of 400 pediatric patients, classified into an asthma group (n = 200) and a no-asthma group (n = 200). According to the BMI z-score all subjects were classified into normal-weight patients (NW; -2 ≤ BMI z-score <1) and overweight patients/patients with obesity (OW/OB; BMI z-score ≥1). Lung function parameters were measured by spirometry. BMI and eFM were considered as adiposity indices. RESULTS: Excess weight/obesity was present in 37 % of patients. The OW/OB group showed higher basal forced expiratory vital capacity (FVC) and lower forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio compared to the NW group (p ≤ 0.01). FVC and FEV1 were correlated with the BMI z-score, and FEV1/FVC with eFT (p ≤ 0.01). No differences were noted between the NW and the OW/OB groups in terms of respiratory parameters except for FVC (p < 0.01). In the OW/OB group, asthma patients were significantly different based on FEV1, FEV1/FVC, and forced expiratory flow at 25-75 % of FVC (FEF25/75) (p < 0.01). The BMI z-score was correlated with FVC and FEV1 in both the no-asthma and asthma groups (p ≤ 0.01 and p ≤ 0.05, respectively), while eFM was correlated with FEV1/FVC (p = 0.007) in the asthma group only. CONCLUSION: Obesity seems to have a significant impact on lung function in children with respiratory allergic diseases. BMI and eFM may be used to evaluate the impact of adiposity on lung function.

Nasal spray live attenuated influenza vaccine: the first experience in Italy in children and adolescents during the 2020-21 season.

BACKGROUND: In Italy only recently, for the 2020-21 season, has the flu vaccination been extended to all children. A quadrivalent live attenuated influenza vaccine (qLAIV) was administered to children aged 2-17 years for the first time. We registered the number and severity of adverse reactions to (Fluenz Tetra™) and the factors influencing them, evaluated uniformity of access to care and assessed the degree of satisfaction with the vaccination of both parents and health care providers, in order to improve the 2021-22 vaccination program. METHODS: On vaccination day, a questionnaire was given out to collect information about the children and their parents. Between 1 and 3 months later, the parents were contacted to record any adverse reactions following (Fluenz Tetra™) and rate the degree of satisfaction. RESULTS: We received data of 3226 children from 2152 families. Adverse events were reported in 24.8% of children: 80.6% mild, 18.1% moderate and 1.3% significant. The most common were rhinitis (52.5%) and fever (24.4%). Statistical analysis performed with a multiple regression model, showed that children aged 2-5 years have an increased risk of adverse events compared to both 6-10 years old (aRR 1.7, 95% CI 1.5-1.9, p < 0. 001) and 11-17 years old (aRR 1.5, 95% CI 1-2.2, p = 0.051). Most families chose to vaccinate their children to protect them and because they were concerned about Covid19. The main channel through which parents became aware of a new flu vaccination was word-of-mouth (39.8%), which occurred mostly among parents of the same school group, followed by information from the child's doctor (30.6%), the Internet (26.9%), personal research (15%), newspapers (4%), telecommunications (7.5%) and other (2.6%). Most parents (83.3%) were very satisfied and intend to vaccinate their children with qLAIV again (83.8%). The majority of operators (93%) considered the experience as excellent and are willing to repeat it (94.6%). CONCLUSION: (Fluenz Tetra™) proved to be easy to administer and the degree of satisfaction was high among both health workers and parents. Considering its substantial safety profile especially in school-age children and adolescents, all these aspects make the nasal qLAIV optimal for widespread immunization. Schools offer the best setting to reach more families and physicians should be actively involved.

RelB activation in anti-inflammatory decidual endothelial cells: a master plan to avoid pregnancy failure?

It is known that excessive inflammation at fetal-maternal interface is a key contributor in a compromised pregnancy. Female genital tract is constantly in contact with microorganisms and several strategies must be adopted to avoid pregnancy failure. Decidual endothelial cells (DECs) lining decidual microvascular vessels are the first cells that interact with pro-inflammatory stimuli released into the environment by microorganisms derived from gestational tissues or systemic circulation. Here, we show that DECs are hypo-responsive to LPS stimulation in terms of IL-6, CXCL8 and CCL2 production. Our results demonstrate that DECs express low levels of TLR4 and are characterized by a strong constitutive activation of the non-canonical NF-κB pathway and a low responsiveness of the canonical pathway to LPS. In conclusion, DECs show a unique hypo-responsive phenotype to the pro-inflammatory stimulus LPS in order to control the inflammatory response at feto-maternal interface.

NF-κB pathways in hematological malignancies.

The nuclear factor κB or NF-κB transcription factor family plays a key role in several cellular functions, i.e. inflammation, apoptosis, cell survival, proliferation, angiogenesis, and innate and acquired immunity. The constitutive activation of NF-κB is typical of most malignancies and plays a major role in tumorigenesis. In this review, we describe NF-κB and its two pathways: the canonical pathway (RelA/p50) and the non-canonical pathway (RelB/p50 or RelB/p52). We then consider the role of the NF-κB subunits in the development and functional activity of B cells, T cells, macrophages and dendritic cells, which are the targets of hematological malignancies. The relevance of the two pathways is described in normal B and T cells and in hematological malignancies, acute and chronic leukemias (ALL, AML, CLL, CML), B lymphomas (DLBCLs, Hodgkin's lymphoma), T lymphomas (ATLL, ALCL) and multiple myeloma. We describe the interaction of NF-κB with the apoptotic pathways induced by TRAIL and the transcription factor p53. Finally, we discuss therapeutic anti-tumoral approaches as mono-therapies or combination therapies aimed to block NF-κB activity and to induce apoptosis (PARAs and Nutlin-3).

RelB/p50 regulates TNF production in LPS-stimulated dendritic cells and macrophages.

Dendritic cells (DCs) and macrophages are effective antigen-presenting cells, and DCs, once matured, have the ability to potently activate naïve T cells. While the canonical p65/p50 NF-κB pathway seems to have an important role during LPS-stimulation of these cells, the specific contribution of the non-canonical RelB/p50 subunits is not clear yet. We aimed to investigate the relevance of this pathway in DCs and macrophages by using replication-deficient adenoviruses overexpressing RelB and p50 subunits to test their effect on cytokine production. In both cells, after LPS treatment, overexpression of RelB and p50 inhibited the production of some pro-inflammatory cytokines e.g., TNF, but not of others e.g. IL6. Anti-inflammatory IL10 was not affected. Moreover, when overexpressing p50 alone, IL10 was increased in LPS-activated macrophages. We thus demonstrated that the dimer RelB/p50 rather than the p50/p50 complex inhibits TNF production in LPS-stimulated DCs and macrophages. This implies that the non-canonical RelB/p50 could modulate the canonical p65/p50 pathway.

NF-κB as a target for modulating inflammatory responses.

The inflammatory response is of major importance in host defence, but is involved in all acute and chronic diseases. Multiple inflammatory cells and molecules are involved. Among the latter, the Nuclear Factor -κB (NF-κB) has been found to be most important and present in all cell types. NF-B regulates the expression of a large number of genes involved in inflammation. NF-κB plays a key role in the orchestration of the multifaceted inflammatory response, not only in the first pro-inflammatory phase, but also later in the regulation of the resolution of inflammation, when anti-inflammatory genes are expressed and apoptosis is induced. The review describes NF-κB and its two pathways: the canonical, mediated by the p65 and p50 subunits, and the non-canonical, mediated by the subunits RelB, p52 and p50. The relevance of the kinases and interactions leading to NF-κB activation is considered in different primary cells (i.e. macrophages, dendritic cells, fibroblasts, cells from inflammatory tissues), together with the response induced and the ligand involved. Then we overview the different steps to NF-B activation that can be targeted (IKKs, IκBα or NF-κB subunits themselves) with various technologies available i.e. small molecules peptides or nucleic acids. A rationale is provided for possible targets to consider, in the light that NF-κB signaling pathways regulates both pro-inflammatory and anti-inflammatory responses. The possibility of using NF-κB targeted dendritic cells in immunotherapy is considered.

The MDM2 inhibitor Nutlin-3 modulates dendritic cell-induced T cell proliferation.

Nutlin-3, a small molecule inhibitor of the MDM2/p53 interaction, has been recently taken into consideration as a promising therapeutic tool for tumor treatment based on its ability to stabilize and activate the p53 transcription factor pathway. Since Nutlin-3 displays non cell-autonomous tumor-suppressor activities, we wanted to investigate its effect on dendritic cell functions, given the central role of these cells in the modulation of the immune response. We found that Nutlin-3 alone slightly affected the levels of major histocompatibility complex and costimulatory molecules and significantly promoted the ability of dendritic cells to stimulate T cells in the mixed lymphocyte reaction. Taken together, our findings suggest that the ability of Nutlin-3 to modulate dendritic cell functions and therefore lymphocyte proliferation might represent an additional important mechanism by which Nutlin-3 exerts its non cell-autonomous tumor-suppression function.

RelB/p50 regulates CCL19 production, but fails to promote human DC maturation.

DC, when fully matured are the APC best able to activate naïve T cells. Recently, we demonstrated using adenoviruses overexpressing IkappaBalpha and proteosome inhibitors that NF-kappaB is involved in DC activation, but the role of the individual subunits is still not clear. We investigated the role of the NF-kappaB subunits RelB and p50 in human DC activation using adenoviral vectors expressing RelB or p50. Nuclear RelB, in the form of RelB/p50, was active only in DC infected with both viruses, this induced the production of the soluble homeostatic chemokine CCL19, but not other homeostatic chemokines, particularly in LPS-matured DC. However, RelB/p50 did not affect the expression of costimulatory and antigen-presenting molecules, and increased the allogeneic mixed lymphocyte reaction only in LPS-matured DC. This enhanced mixed lymphocyte reaction is most likely due to enhanced CCL19 production, which sustains the interaction between mature DC and naïve T cells. In conclusion, we demonstrated that RelB/p50 was active only in DC expressing both RelB and p50, and induced CCL19 production, but not DC maturation.

Safe administration of an inactivated virosomal adjuvanted influenza vaccine in asthmatic children with egg allergy.

In order to evaluate whether the virosomal adjuvanted influenza vaccine that has been shown to have the lowest egg protein content (Inflexal V, Berna Biotech) could be administered to children with even severe egg allergy without any risk of allergic reactions, we used epicutaneous skin testing with the undiluted vaccine in 88 asthmatic children (44 with and 44 without egg allergy), none of whom had a positive response. They were then vaccinated with the whole dose of Inflexal V intramuscularly in a one-dose protocol, and the occurrence of any immediate or delayed adverse events were actively monitored for 28 days. The results showed the safety of the administration, and demonstrated that Inflexal V can be safely given without performing a vaccine skin test in children with any kind of egg allergy.

Evidence that elastase is the TNF-R75 shedding enzyme in resting human polymorphonuclear leukocytes.

We previously showed that a metalloprotease and a serine protease mediate shedding of the TNF-R75 (75-kDa tumor necrosis factor receptor) in neutrophils. Here we show that elastase is the TNF-R75 solubilizing serine protease. Release of the TNF-R75 by resting cells was almost totally inhibited by the serine protease inhibitor diisopropylfluorophosphate (DFP), by two synthetic, chemically unrelated, elastase-specific inhibitors and by alpha1-protease inhibitor. Release after TNF or FMLP (N-formyl-L-methionyl-L-leucyl-L-phenylalanine) stimulation was blocked by DFP and a metalloprotease inhibitor used in combination. Supernatants from resting neutrophils contained a 28-kDa fragment of the receptor, compatible with that generated by elastase, whose appearance was inhibited by DFP. Upon FMLP stimulation, the release of 28-kDa and 40-kDa fragments was observed, which was inhibited by DFP and a metalloprotease inhibitor, respectively. We conclude that elastase is the TNF-R75 sheddase of resting neutrophils and that it contributes to shedding of this receptor in stimulated cells.