Our results indicate that lysates derived from heat-shocked tumor cells are an optimal source of tumor-associated Ags, which are crucial for the generation of DCs with improved Ag cross-presentation capacity and clinically effective immunogenicity.

Toll-like receptor 4 (TLR4) is expressed on dendritic cells (DCs), sensing environmental danger molecules that induce their activation and maturation. Recently, we reported a method for the production of therapeutic DCs against melanoma, called tumor antigen-presenting cells (TAPCells), using a heat-shocked allogeneic melanoma cell lysate (TRIMEL) as an activation factor and antigen provider. Since TRIMEL contains endogenous TLR4 ligands, we evaluated the role of TLR4 in TAPCells differentiation by antibody neutralization and the association of a Tlr4 polymorphism (896A/G) (Asp299Gly), determined by PCR-RFLP, with the in vitro activation capacity and the clinical outcome of TAPCells-vaccinated patients. Antibody blocking of monocyte TLR4 inhibited surface expression, determined by flow cytometry, of the major histocompatibility complex class I, CCR7, CD80, CD83 and CD86 on TAPCells, reduced interleukin (IL)-6 and tumor necrosis factor -α gene expression evaluated by qRT-PCR, and also inhibited the TAPCells-mediated interferon-γ (IFN-γ) secretion of melanoma-specific CD8(+) T cells determined by ELISpot (p < 0.01). Moreover, CD8(+) T-cell activation capacity was significantly reduced in TAPCells bearing the TLR4 Asp299Gly receptor (p < 0.05). Finally, TAPCells-vaccinated stage-IV melanoma patients bearing the Tlr4 896G allele showed a shortened post-therapy median survival rate compared with those carrying the Tlr4 896A allele (p < 0.05; log-rank test). Our results indicate that TLR4 is a key receptor for the tumor lysate-mediated in vitro generation of clinically efficient antigen-presenting cells. Further analysis of patients included in different vaccine protocols is necessary for definitively establishing a role for TLR4 polymorphism in clinical responses.

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To evaluate the effectiveness of an integrated emergency department (ED)/hospital at home (HH) medical care model in mild COVID-19 pneumonia and evaluate baseline predictors of major outcomes and potential savings. Retrospective cohort study with patients evaluated for COVID-19 pneumonia in the ED, from March 3 to April 30, 2020. All of them were discharged home and controlled by HH. The main outcomes were ED revisit and the need for deferred hospital admission (protocol failure). Outcome predictors were analyzed by simple logistic regression model (OR; 95% CI). Potential savings of this medical care model were estimated. Of the 377 patients attended in the ED, 109 were identified as having mild pneumonia and were included in the ED/HH medical care model. Median age was 50.0 years, 52.3% were males and 57.8% had Charlson index ≥ 1. The median HH stay was 8 (IQR 3.7–11) days. COVID-19-related ED revisit was 19.2% ( n = 21) within 6 days (IQR 3–12.5) after discharge from ED. Overall protocol failure (deferred hospital admission) was 6.4% ( n = 7), without ICU admission. The ED/HH model provided potential cost savings of 77% compared to traditional stay, due to the costs of home care entails 23% of the expenses generated by a conventional hospital stay. 789 days of hospital stay were avoided by HH, rather than hospital admission. An innovative ED/HH model for selected patients with mild COVID-19 pneumonia is feasible, safe and effective. Less than 6.5% of patients requiring deferred hospital admission and potential savings were generated due to hospitalization. Supplementary Information The online version contains supplementary material available at 10.1007/s11739-021-02661-8.