Background: Sepsis remains a major cause of morbidity and mortality in both developed and limited-resource countries. Despite over a century of research, accurate biomarkers for reliable diagnosis and prognosis in critically ill patients have yet to be established. Methods: This multicenter retrospective observational study aims to evaluate serum levels of Calprotectin, Azurocidin, cytokines, chemokines, procalcitonin (PCT) and C-Reactive Protein (CRP) in 15 healthy volunteers (controls), 15 non-infectious SIRS patients, 92 alive septic patients (Sepsis_A) and 29 dead septic patients (Sepsis_D). Results: Most biomarkers showed significantly higher serum concentrations in septic patients compared with controls, with IL-4 being increased only in the Sepsis_D group. In addition, several markers, including Calprotectin, Azurocidin, IL-6, IL-8, IL-10, TNF-α, and IL-35, were progressively elevated from SIRS to Sepsis_A and Sepsis_D cohorts, reflecting disease severity. All biomarkers showed good diagnostic performance for predicting Gram-negative bacteremia, although their accuracy in discriminating survivors from non-survivors was relatively low. Conclusions: In conclusion, calprotectin, azurocidin, IL-8, TNF-α, and IL-35 may assist clinicians in identifying Gram-negative bacteremia in septic patients; however, their prognostic value appears to be limited.

Concomitant immunity (CI) can be viewed as an example of coevolution between the microorganisms and their long-lived hosts. Such an ecological trade-off may be advantageous to both the microbe and the host, as it allows protozoa and helminths to maintain their genetic features while providing the host, particularly mammals, with long-standing protection against reinfection by the same microbe. In Leishmania infection, CI is the mechanism whereby parasites remain at low-level infection in the host, which develops a strong immune reaction that protects against reinfection. Mechanistically, several CD4 ⁺ T cell populations seem to be involved in such fine immune responses. While immunity against Leishmania , Plasmodium , Taenia , Schistosoma , and Echinococcus is well known, the mechanisms of CI involving these pathogens have been poorly studied. Finally, the phenomenon of CI should be carefully assessed in the design of novel vaccine preparations. Graphical Abstract

The purpose of this review is to address some of the latest aspects regarding molecular features, pathogenic mechanisms, and immune system response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), based on recent publications in this field from March 2020 to May 2021. Interpretation keys for periodic re-emergence of coronavirus infections and other lethal viral pandemics are suggested. Antibody-dependent enhancement (ADE) and other potential mechanisms of immune system deception are put forward. Therefore, vaccine development must take into account ADE and other unwanted side effects of immune-based medical intervention. Features reported in our review will allow both clinicians and basic science researchers to take home ideas to improve their knowledge about SARS-CoV-2.

Acute interstitial nephritis (AIN) due to helminths is a rare cause of acute kidney injury (AKI). Helminthiases often progresses insidiously, making diagnosis difficult. This was the case of a 72-year-old man, who presented with renal failure, itching and diarrhoea. Urinalysis revealed leukocyturia, microhaematuria and mild proteinuria. A full blood count revealed leucocytosis with eosinophilia. A stool parasitological examination revealed fertilised eggs of Ascaris lumbricoides. Tubulointerstitial nephropathy secondary to A. lumbricoides infection was suspected. A percutaneous renal biopsy was not performed since the patient refused the anti-platelet therapy discontinuation. Mebendazole, albendazole and prednisone therapy was administered. After worm eradiation and discharge, recovery from the parasitosis, absence of pruritus and eosinophilia, and progressive improvement of renal function were observed, strongly suggesting a causal relationship between Ascaris infection and AIN. Parasite infection should be considered in the differential diagnosis of unexplained renal failure because early diagnosis and treatment are necessary to avoid irreversible complications.

The host response to helminth infections is characterized by systemic and tissue-related immune responses that play a crucial role in pathological diseases. Recently, experimental studies have highlighted the role of regulatory T (Tregs) and B (Bregs) cells with secreted cytokines as important markers in anti-schistosomiasis immunity. We investigated the serical levels of five cytokines (TNFα, IFN-γ, IL-4, IL-10 and IL-35) in pre- and post-treatment samples from chronic Schistosoma infected patients to identify potential serological markers during follow-up therapy. Interestingly, we highlighted an increased serum level of IL-35 in the pre-therapy samples (median 439 pg/mL for Schistosoma haematobium and 100.5 pg/mL for Schistsoma mansoni infected patients) compared to a control group (median 62 pg/mL and 58 pg/mL, respectively, p ≤ 0.05), and a significantly lower concentration in post-therapy samples (181 pg/mL for S. haematobium and 49.5 pg/mL for S. mansoni infected patients, p ≤ 0.05). The present study suggests the possible role of IL-35 as a novel serological biomarker in the evaluation of Schistosoma therapy follow-up.