Long-term outcomes of bictegravir/emtricitabine/tenofovir alafenamide as first-line therapy and as switch strategy in virologically suppressed persons with HIV: data from the ICONA cohort.

OBJECTIVES: To assess the effectiveness of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) among people poorly represented in clinical trials and potentially at higher risk of suboptimal response to ART. METHODS: Observational cohort study on persons with HIV (PWH) enrolled in ICONA who started BIC/FTC/TAF as initial therapy or as switching regimen while virologically suppressed. Primary endpoint was time to treatment failure (TF): new AIDS/death or virological failure (VF) or discontinuation for toxicity/failure. Secondary endpoints were time to treatment discontinuation for toxicity (TDT) and to VF. Groups of interest were those aged >50 years, female sex, and advanced HIV disease at first ART start. Probability of the events overall and according to groups and adjusted HR for every endpoint were calculated by Kaplan-Meier curves and Cox regression models. RESULTS: Nine hundred and thirty-three ART-naive and 1655 ART-experienced PWH initiated BIC/FTC/TAF. Over a median follow-up of 69.8 weeks, 89 (9.6%) PWH at their first regimen experienced TF. PWH aged >50 years had 1.83-fold (95% CI: 1.19-2.83) higher risk of TF; PWH with advanced HIV disease had 2.21-fold (95% CI: 1.53-3.82) higher risk; there were no differences in TF according to sex.Over a median follow-up of 146.3 weeks, 109 (6.6%) out of 1655 switching PWH experienced TF; no differences were found in the risk of TF, TDT and VF according to groups of interest. CONCLUSIONS: Overall, BIC/FTC/TAF is well tolerated and virologically effective in the real-world scenario for ART-naive and -experienced PWH. Older ART-naive PWH and those with advanced HIV disease may respond less well as the burden of diseases might compromise treatment efficacy.

IL-1 Receptor Antagonist Anakinra in the Treatment of COVID-19 Acute Respiratory Distress Syndrome: A Retrospective, Observational Study.

The IL-1 receptor antagonist, anakinra, may represent a therapeutic option for acute respiratory distress syndrome (ARDS) associated with coronavirus disease 2019 (COVID-19). In this study, COVID-19 ARDS patients admitted to the Azienda Socio Sanitaria Territoriale of Lecco, Italy, between March 5th to April 15th, 2020, and who had received anakinra off-label were retrospectively evaluated and compared with a cohort of matched controls who did not receive immunomodulatory treatment. The primary end point was survival at day 28. The population consisted of 112 patients (56 treated with anakinra and 56 controls). Survival at day 28 was obtained in 69 patients (61.6%) and was significantly higher in anakinra-treated patients than in the controls (75.0 versus 48.2%, p = 0.007). When stratified by continuous positive airway pressure support at baseline, anakinra-treated patients' survival was also significant compared with the controls (p = 0.008). Univariate analysis identified anakinra usage (odds ratio, 3.2; 95% confidence interval, 1.47-7.17) as a significant survival predictor. This was not supported by multivariate modeling. The rate of infectious-related adverse events was similar between groups. In conclusion, anakinra improved overall survival and invasive ventilation-free survival and was well tolerated in patients with ARDS associated with COVID-19.

Post-neurosurgical Nocardia meningoventriculitis: a case report and review of the literature.

The genus Nocardia consists of a group of gram-positive environmental bacteria. They typically cause lung and brain infections in immunocompromised patients, even though one out of three infected patients have a normally functioning immune system. Being a ubiquitous microorganism, in some cases Nocardia has been associated with nosocomial acquired infections and surgical procedures. A review of the literature in this field follows the case report. A 47-year-old woman underwent an endoscopic third ventriculostomy and a left retro-sigmoid craniotomy for a schwannoma removal. Meningeal symptoms began a week later, in association with C reactive protein rise and leukocytosis. Cerebrospinal fluid (CSF) examination was clear with hypoglycorrhachia, hyperprotidorrachia and polymorphonuclear cells. Cultural exam was negative. At the brain magnetic resonance imaging (MRI) purulent material was described in the occipital ventricular horns. Empirical broad spectrum antibiotic therapy was given for 31 days until the brain MRI showed a resolution of the infection. Ten days later, the patient was admitted to the hospital because of new meningeal symptoms. Cerebrospinal fluid culture and Polymerase-chain reaction (PCR) Multiplex for the most important meningitis viruses and bacteria tested negative. A broad-spectrum antibiotic therapy was started with no benefit; thus, a broad-spectrum antifungal therapy was added with little success on clinical status. Meanwhile, a 16s and 18s rRNA PCR was executed on a previous Cerebrospinal fluid with negative results, excluding bacterial and fungal infections. For this reason, all the therapies were stopped. After a few days, high fever and meningeal signs reappeared. The brain MRI showed a meningoventriculitis. An Ommaya catheter with reservoir was inserted and the drawn CSF resulted in the growth of Nocardia farcinica. Antibiogram-based antibiotic therapy was started with intravenous imipenem and trimethoprim-sulfamethoxazole, showing clinical benefit. The patient was sent home with oral linezolid and amoxicillin/clavulanate for a total of 12 months of therapy. Nocardia rarely causes post-neurosurgical complication in a nosocomial setting. This case shows the difficulty in detecting Nocardia and the importance of the correct microbiological sample and antibiogram-based antibiotic therapy to achieve successful treatment.

Impact of prolonged maraviroc treatment on non-AIDS-related comorbidities in HIV-positive patients: a retrospective cohort study.

OBJECTIVES: This retrospective study evaluates the effect of maraviroc, the first CCR5 receptor antagonist, on non-AIDS-related comorbidity incidence and its impact on inflammatory and lipid parameters. METHODS: Seventy-four HIV patients on maraviroc treatment were compared with 312 patients never exposed to maraviroc (matched for sex, age and CD4 nadir). RESULTS: At baseline (T0), maraviroc patients presented a longer duration of HIV infection, a higher prevalence of comorbidities and a greater frequency of polypharmacy. Non-AIDS-defining disease incidence was lower in the maraviroc group than in the non-maraviroc group (without achieving statistical significance). Except triglycerides (TGL), which dropped only in the maraviroc group, inflammatory and immunological parameters did not significantly change in either group by the end of the study period (T3). At T3, high-sensitivity C-reactive protein (hsCRP) and high-density lipoprotein were inversely correlated in both groups (Spearman's rho: maraviroc -0.30, P = 0.05; non-maraviroc -0.23, P = 0.0003). Only in the non-maraviroc group was the positive correlation between hsCRP and lipids observed both at T0 (hsCRP/low-density lipoprotein (LDL) +0.17, P = 0.004; hsCRP/total cholesterol +0.20, P = 0.0007; hsCRP/TGL +0.12, P = 0.04) and T3 (hsCRP/LDL +0.26, P < 0.0001; hsCRP/total cholesterol +0.24, P = 0.0001; hsCRP/TGL +0.15, P = 0.02). These correlations were not found in the maraviroc group. A significant positive correlation was found at T0 and at T3 between hsCRP and D-dimer in both groups (maraviroc: T0 +0.46, P = 0.0007; T3 +0.41, P = 0.006; non-maraviroc: T0 +0.17, P = 0.02; T3: +0.17, P = 0.017). CONCLUSIONS: These data suggest a possible protective role of maraviroc in the incidence of non-AIDS-related comorbidities in a population with longer-lasting infection and allow us to hypothesize its role in the modulation of lipid-dependent inflammation.

Successful ceftazidime-avibactam treatment of post-surgery Burkholderia multivorans genomovar II bacteremia and brain abscesses in a young lung transplanted woman with cystic fibrosis.

Burkholderia cepacia complex (Bcc) includes several phenotypically similar but genotypically distinct gram-negative bacteria (GNB) that can colonize the respiratory tract of Cystic Fibrosis (CF) patients. Pathogens are difficult to treat due to intrinsic resistance to multiple antibiotics and are associated to a more rapid decline in lung function and to increased mortality, particularly after lung transplantation. For all these reasons, chronic infection by Burkholderia (B) cenocepacia is presently considered a relative or absolute contraindication in almost all lung transplant centres. We report the case of a young adult CF patient chronically colonized by B multivorans genomovar II, with diabetes and end-stage renal disease treated with renal replacement therapy: a few months after lung transplantation, she developed post-surgery B multivorans bacteremia and multiple brain abscesses. This severe infection did not improve despite multiple standard antibiotic regimen. The introduction of ceftazidime-avibactam, a new ß-lactam/ ß-lactamase inhibitor combination resulted in clinical recovery and in radiological and biochemical improvement.

Persistent and severe hypoglycemia associated with trimethoprim-sulfamethoxazole in a frail diabetic man on polypharmacy: A case report and literature review
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OBJECTIVE: Trimethoprim-sulfamethoxazole (co-trimoxazole) is a commonly used broad-spectrum antibiotic, but it can be associated with potentially serious adverse effects, often not recognized by clinicians. This is a relevant problem in elderly patients, who are particularly susceptible to adverse drug reactions. Moreover, multiple medications taken by older people increase the risk for adverse drug reactions and drug-drug interactions. CASE REPORT: We report the case of an 85-year-old man with diabetes mellitus who attended the emergency room with severe hypoglycemia that persisted despite multiple intravenous bolus doses and continuous infusion of glucose. He needed hospital admission to stabilize glycemia. The patient, a nursing home resident, was being treated with co-trimoxazole for an uncomplicated urinary tract infection, but was also taking multiple additional drugs for his co-morbidities. After co-trimoxazole was discontinued, plasma glucose levels slowly stabilized within the normal range. A diagnosis of prolonged and refractory hypoglycemia induced mainly by the antimicrobial agent was made, with additional contribution from multiple other drugs. No further episodes of hypoglycemia occurred during the next 6 months of follow-up. CONCLUSION: This case study illustrates once more the critical importance of prescription appropriateness in elderly patients with multiple morbidities in terms of type and dosage of drugs, in order to avoid serious adverse reactions.
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Antiretroviral therapy in geriatric HIV patients: the GEPPO cohort study.

Background: GEPPO is a prospective observational multi-centric cohort including HIV-infected geriatric patients. We hypothesized that the GEPPO cohort may help characterize antiretroviral (ARV) prescribing criteria used in real life by Italian infectious disease (ID) physicians. Methods: This was a cross-sectional study describing the current ARV regimen in a geriatric HIV population (≥65 years). Antiretroviral strategies were categorized as follows: (i) multidrug regimens (MDRs), which comprised triple or mega ART combinations; (ii) less drug regimens (LDRs), which comprised fewer than three ART compounds. Multi-morbidity (MM) was defined as the presence of three or more non-communicable diseases, and polypharmacy (PP) as the use of five or more medications in chronic use. Four alternative combinations (MM+PP+, MM+PP-, MM-PP+, MM-PP-) were used in logistic regression analyses. Results: A total of 1222 HIV-positive patients were included (median age 70 years). Females composed 16% of the cohort. Median duration of HIV infection was 17 years; 335 population members had been infected for >20 years. MM was present in 64% and PP in 37% of the patients. Treatment consisted of triple therapy in 66.4%, dual therapy in 25.3%, monotherapy in 6.5% and 'mega-ART' with more than three drugs in 1.64% of the patients. In multivariate logistic regression MM and PP were predictive for mono-dual, NRTI-sparing and tenofovir disoproxil fumarate (TDF)-sparing combinations. Female gender and age were predictors of unboosted ARV regimens. Conclusions: High prevalence of non-conventional ARV regimens in elderly HIV patients suggests that clinicians try to tailor ARV regimens according to age, HIV duration, MM and PP.

Hydroxychloroquine drastically reduces immune activation in HIV-infected, antiretroviral therapy-treated immunologic nonresponders.

Despite optimal suppression of HIV replication, restoration of CD4(+) T cells is not always achieved in antiretroviral therapy-treated individuals. Defective CD4 recovery in immunologic nonresponders is possibly associated with TLR-mediated immune activation driven by alterations of gut permeability. Hydroxychloroquine (HCQ) reduces endosomal TLR signaling; thus, we verified whether HCQ could dampen immune activation and be associated with an increase in CD4(+) T cells. To this end, we enrolled in a prospective study 20 HIV-infected immunologic nonresponders (CD4 count < 200 cells/mL or CD4 increase < 5% in the last 12 months) who received 400 mg/day HCQ for 6 months. HCQ had a notable impact on immune activation as shown by significant modifications of the following parameters: (1) reduced plasma lipopolysaccharide; (2) decreased TLR4-expressing CD14(+) cells, TLR4-mediated signal transduction, and mRNA synthesis; (3) reduced percentages of activated CD4(+) (CD4(+)/Ki67(+)) and CD14(+) (CD14(+)/CD69(+)) cells; (4) increased T-regulatory cells (Tregs), naive Tregs, and TLR4-expressing Tregs; (5) augmented plasmacytoid dendritic cells and reduced IFNα-secreting plasmacytoid dendritic cells; and (6) reduced IL-6 and TNFα production. HCQ-induced immune modulation was associated with increased percentages of circulating CD4(+) T cells and was mostly retained 2 months after therapy interruption. HCQ reduces lipopolysaccharide/TLR-mediated immune activation; this compound could be a useful immunomodulant in HIV-infected patients. This study is registered at EutraCT as 2009-012499-28 with study number HLS01/2009-1-16-03-2009.

Surgical site infections in liver transplantation in the era of multidrug-resistant bacteria.

BACKGROUND: Surgical site infection (SSI) is the major complication in orthotopic liver transplantation (LT). It is of prime importance to assess the incidence of infections in liver transplants and to analyze the risk factors associated with morbidity and mortality. METHODS: Between 2014 and 2019, we performed a retrospective cohort study at the Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. The liver transplant procedure and its related infections were examined in 4 timepoints, both prior and post-surgery. Multiple random-intercept Poisson regression models with robust variance were fitted to calculate the adjusted risk ratios (RR) and the 95% confidence intervals (CI) according to selected recipient and donor variables. RESULTS: We included in the analysis 249 transplants (in 241 patients). The SSIs (mostly due to S. aureus, E. faecium, and K. pneumoniae) were 7 (2.8%) in the days following LT, increasing to 61 (24.5%) within the first month after LT, and declining to 35 (14.1%) between 31 and 60 days, and to 19 (7.6%) afterwards. The factors associated with increased risk of infection were age (RR=1.17 per 10 years, CI: 0.99-1.38), BMI (RR=1.04 per BMI Unit, CI: 0.99-1.08), donor age (RR=0.88 per 10 years, CI: 0.78-0.98), re-interventions (30 infections, RR=2.02, CI: 1.21-3.38) and the Roux-en-Y approach (25 infections, RR=2.75, CI: 1.47-5.15). CONCLUSIONS: The risk of infection occurred mainly in the first two months after LT. Important determinants were age and BMI, donor age, reinterventions, and Roux-en-Y procedure. Our study suggests that these factors should be assessed when performing LT.

Monitoring cognitive and psychological alterations in COVID-19 patients: A longitudinal neuropsychological study.

BACKGROUND: SARS-COV-2 infection has been associated to long-lasting neuropsychiatric sequelae, including cognitive deficits, that persist after one year. However, longitudinal monitoring has been scarcely performed. Here, in a sample of COVID-19 patients, we monitor cognitive, psychological and quality of life-related profiles up to 22 months from resolution of respiratory disease. METHODS: Out of 657 COVID-19 patients screened at Manzoni Hospital (Lecco, Italy), 22 underwent neuropsychological testing because of subjective cognitive disturbances at 6 months, 16 months, and 22 months. Tests of memory, attention, and executive functions were administered, along with questionnaires for depressive and Post-traumatic stress disorder (PTSD) symptoms, psychological well-being and quality of life. Cross-sectional descriptives, correlational, as well as longitudinal analyses considering COVID19-severity were carried out. A preliminary comparison with a sample of obstructive sleep apneas patients was also performed. RESULTS: Around 50% of COVID-19 patients presented with cognitive deficits at t0. The most affected domain was verbal memory. Pathological scores diminished over time, but a high rate of borderline scores was still observable. Longitudinal analyses highlighted improvements in verbal and non-verbal long term memory, as well as attention, and executive functioning. Depression and PTSD-related symptoms were present in 30% of patients. The latter decreased over time and were associated to attentional-executive performance. CONCLUSIONS: Cognitive dysfunctions in COVID-19 patients may extend over 1 year, yet showing a significant recovery in several cases. Cognitive alterations are accompanied by a significant psychological distress. Many patients displaying borderline scores, especially those at higher risk of dementia, deserve clinical monitoring.

Real-life safety of Emtricitabine/Tenofovir Alafenamide/Bictegravir.

INTRODUCTION: Integrase strand transfer inhibitors (INSTI) are one of the most prescribed drug classes for the treatment of HIV infection worldwide. Emtricitabine/Tenofovir Alafenamide/ Bictegravir (FTC/TAF/BIC) has been evaluated in randomized clinical trials; few studies have verified tolerability and safety in clinical practice. Our aim was to investigate the metabolic and hepatic safety in a real-life setting of FTC/TAF/BIC. MATERIALS AND METHODS: Consecutive people living with HIV infection (PLWH) enrolled in the SCOLTA project, switching to or initiating their first antiretroviral treatment with FTC/TAF/BIC were included. PLWH with HBV co-infection were excluded. Metabolic and hepatic variables were collected at T0 and T1, were defined as baseline and 6-month follow-up respectively, and their modifications were analysed using the paired t-test and the analysis of variance. RESULTS: Five hundred and thirty-nine PLWH with at least one follow-up visit were included in the analysis. Mean age was 48 years (±12.1), 74% were male, 16.1% were naïve to antiretrovirals (ART). At T1, ART-experienced PLWH showed a significant reduction of total cholesterol (TC) and triglycerides, and a slight increase in blood glucose (BG) and ALT. On the contrary, in ART-naïve PLWH blood lipids significantly increased, although with an unaffected TC/high density lipoprotein (HDL)-c ratio, while alanine aminotransferase (ALT) decreased significantly, mainly in those with altered baseline level. The treatment interruptions were 45 (8.4%) over the whole observation period, 13 (2.4%) due to AEs. The most frequent AEs were related to the central nervous system (6 events of depression, insomnia, headache, agitation) and 3 PLWH discontinued the regimen because of grade 1-2 weight gain. CONCLUSIONS: In ART-experienced PLWH switching to FTC/TAF/BIC a significant improvement of lipid profile occurred but with significant BG and ALT variation without clinical relevance. In ART-naïve PLWH, blood lipids increased even though lipid profile did not worsen, and a trend towards normalization of liver enzymes was suggested. FTC/TAF/BIC is well tolerated in the real life setting.

SARS-CoV-2 mRNA Vaccine Response in People Living with HIV According to CD4 Count and CD4/CD8 Ratio.

BACKGROUND: Our aim was to estimate the rates of not achieving a robust/above-average humoral response to the COVID-19 mRNA vaccine in people living with HIV (PLWH) who received ≥2 doses and to investigate the role of the CD4 and CD4/CD8 ratio in predicting the humoral response. METHODS: We evaluated the humoral anti-SARS-CoV-2 response 1-month after the second and third doses of COVID-19 mRNA vaccine as a proportion of not achieving a robust/above-average response using two criteria: (i) a humoral threshold identified as a correlate of protection against SARS-CoV-2 (<90% vaccine efficacy): anti-RBD < 775 BAU/mL or anti-S < 298 BAU/mL, (ii) threshold of binding antibodies equivalent to average neutralization activity from the levels of binding (nAb titer < 1:40): anti-RBD < 870 BAU/mL or anti-S < 1591 BAU/mL. PLWH were stratified according to the CD4 count and CD4/CD8 ratio at first dose. Logistic regression was used to compare the probability of not achieving robust/above-average responses. A mixed linear model was used to estimate the mean anti-RBD titer at various time points across the exposure groups. RESULTS: a total of 1176 PLWH were included. The proportions of participants failing to achieve a robust/above-average response were significantly higher in participants with a lower CD4 and CD4/CD8 ratio, specifically, a clearer gradient was observed for the CD4 count. The CD4 count was a better predictor of the humoral response of the primary cycle than ratio. The third dose was pivotal in achieving a robust/above-average humoral response, at least for PLWH with CD4 > 200 cells/mm3 and a ratio > 0.6. CONCLUSIONS: A robust humoral response after a booster dose has not been reached by 50% of PLWH with CD4 < 200 cells mm3. In the absence of a validated correlate of protections in the Omicron era, the CD4 count remains the most solid marker to guide vaccination campaigns in PLWH.

Changing of fecal flora and clinical effect of L. salivarius LS01 in adults with atopic dermatitis.

GOAL: To evaluate cytokine stimulation with 3 strains of Lactobacillus salivarius in vitro and to assess changes in intestinal microflora and clinical improvements in adults with atopic dermatitis (AD) induced by the strain showing the best immunomodulatory features. BACKGROUND: AD is a common skin disease in children and adults. It is characterized by chronic inflammation, eczema, and increasing intestinal permeability. Various studies have shown that patients with AD presented some modifications in the intestinal microbiota composition; as a result, intestinal microflora is thought to have a pivotal role in this disease. METHODS: Thirty-eight patients aged from 18 to 46 years with moderate/severe AD were recruited. Subjects were randomized in a double-blind placebo-controlled study to receive active treatment with L. salivarius LS01: probiotic (n=19) or placebo (n=19). Cytokine production was determined by means of specific quantitative enzyme-linked immunosorbent assays. Intestinal bacterial groups were quantified using conventional culture techniques, whereas L. salivarius LS01 was identified using polymerase chain reaction and pulse field gel electrophoresis. RESULTS: L. salivarius LS01 showed the best immunomodulatory features and it was chosen for the second phase of the study. AD subjects showed a reduction in their SCORAD score after probiotic treatment and a significant decrease in the staphylococci load compared with the placebo group. Moreover, L. salivarius LS01 showed the ability to reduce the production of Th2 cytokines, maintaining the production of Th1 cytokines stable. CONCLUSIONS: Treatment with the L. salivarius LS01 strain seems to positively modify clinical and immunologic status and dermatology life quality in a group of adults affected by moderate/severe AD, leading to a rebalancing of altered intestinal microbiota.

Probiotics reduce gut microbial translocation and improve adult atopic dermatitis.

BACKGROUND: It has been suggested that probiotics modulate atopic dermatitis (AD) progression, but no data are actually available on their mechanisms of action and on their ability to act as immunomodulators in this pathology. OBJECTIVE: The aim of this randomized double-blinded active treatment versus placebo study was to evaluate clinical efficacy of an intake of a combination of 2 probiotics (Lactobacillus salivarius LS01 and Bifidobacterium breve BR03) for the treatment of adult AD patients. METHODS: Forty-eight patients were enrolled in the study (randomization ratio 2:1) and treated with a combination (LS01 and BR03) or placebo (maltodextrin) for 12 weeks. Clinical efficacy was assessed from baseline by changes in the SCORAD index and DLQ index improvement. Analysis on the gut permeability barrier, immunologic parameters, and changes in fecal microbiota and recovery of probiotics were performed at baseline, at the end of therapy, and 2 months later. RESULTS: Patients receiving probiotics showed a significant improvement in clinical parameters (SCORAD, P<0.0001 and DLQ index, P=0.021) from baseline. The probiotics reduced microbial translocation (P=0.050), immune activation (P<0.001), improved T-helper cell (Th)17/regulatory T cell (Treg) (P=0.029) and Th1/Th2 (P=0.028) ratios. None of these changes were observed in the placebo group. CONCLUSIONS: Our results suggest that this specific mixture of probiotics (LS01 and BR03 strains) may induce beneficial effects for clinical and immunologic alterations in adult AD. This combination could be considered as adjuvant therapy for the treatment of AD in adult patients.

Immunological effects of sublingual immunotherapy: clinical efficacy is associated with modulation of programmed cell death ligand 1, IL-10, and IgG4.

Sublingual immunotherapy (SLIT) is an alternate route of administration of allergen-specific immunotherapy with an improved safety profile; to clarify the immune mechanisms elicited by this therapy, we analyzed the clinical and immunologic effects of SLIT in patients with a clinical history of ragweed sensitization. To analyze possible difference among immunotherapeutic protocols, we also compared patients receiving preseasonal, seasonal, or prolonged sublingual therapy (≥ 3 y); patients receiving symptomatic therapy alone were enrolled as well in the study. Clinical and immunological parameters were measured twice in and out of the pollination period. Clinical benefits, as measured by the visual analog scale for symptoms and for use of drugs, were evident in all three groups of individuals receiving immunotherapy, but were significantly better in patients undergoing prolonged SLIT. Immunologically, SLIT resulted in increased IL-10 production, programmed cell death ligand 1 expression, and concentration of allergen-specific IgG4, as well as in the reduction of CD80 and CD86 expression and IL-4 production. SLIT, thus, is associated with modulation of programmed cell death ligand 1 expression and IL-10 synthesis and favors the production of allergen-specific IgG4. These effects are evident from the first pollen season, independently from therapeutic regimen (preseasonal or seasonal) even if a prolonged treatment is necessary to obtain full clinical efficacy. A more detailed understanding of the interaction of allergen and APCs within the oral mucosa will allow improved targeting of allergy vaccine.