Immune cells undergo different metabolic pathways or immunometabolisms to interact with various antigens. Immunometabolism links immunological and metabolic processes and is critical for innate and adaptive immunity. Although metabolic reprogramming is necessary for cell differentiation and proliferation, it may mediate the imbalance of immune homeostasis, leading to the pathogenesis and development of some diseases, such as autoimmune diseases. Here, we discuss the effects of metabolic changes in autoimmune diseases, exerted by the leading actors of innate immunity, and their role in autoimmunity pathogenesis, suggesting many immunotherapeutic approaches.

Background:The pathogenesis of pSS relies on a complex interplay between both innate and adaptive immune responses in which B cells play a pivotal role. Their chronic aberrant hyperactivation may drive clonal escape and consequent lymphomagenesis [1]. In the last few years, B cells have emerged as potential effector cells, able to release a wide range of cytokines that actively contribute to shape the microenvironment they act in. Recently, IL-40, a novel B cell associated cytokine encoded by an uncharacterized gene (C17orf99; chromosome 17 open reading frame 99) was described. Naïve B cells can express IL-40 at both tissue and peripheral level and the stimulation of B cells with IL-4 and TGF-β significantly increases IL-40 release. In addition, human B cells lymphomas are able to constitutively produce IL-40 [2]. Taking into account this emerging evidence and considering the well-known role of IL-4 and TGF-β in pSS pathogenesis, as well as the association with lymphomas, we decided to focus our attention on IL-40 in pSS patients.Objectives:The aim of the present study was to investigate IL-40 expression in the salivary glands of patients affected by pSS and pSS-associated non-Hodgkin’s lymphoma (NHL).Methods:Minor salivary gland biopsies were obtained from 22 patients with pSS and 12 patients with non-specific chronic sialoadenitis (nSCS), included as controls. Paraffine-embedded samples of parotid glands from patients with a previous diagnosis of pSS-associated NHL (n=10) were selected from the biopsy bank of the Pathology Unit of the Ospedale Cervello (Palermo, Italy). Quantitative gene expression analysis by TaqMan real-time PCR and immunohistochemistry (IHC) for IL-40, IL-4, TGF-β1 was performed on salivary glands from patients and controls. The cellular sources of IL-40 among infiltrating inflammatory cells were determined by fluorescence-activated cell sorting (FACS) analysis and immunofluorescence (IF). Serum IL-40 levels were measured by ELISA in both patients (n=10) and controls (n=9).Results:IL-40 was significantly increased at both protein and mRNA level in the inflamed salivary glands of patients with pSS where a positive strong correlation between the IL-40 mRNA levels and the focus score (FS) was evidenced. The expression of IL-40 in parotid glands of pSS-associated NHL was also markedly increased (Figure 1). IL-40 expression correlated with the presence of IL-4 and TGF-β; both cytokines were significantly increased in pSS at mRNA and protein level. Among infiltrating immune cells, CD19+ B cells resulted the major source of IL-40. However, we identified CD4+, CD8+ T cells and CD68+ macrophages as additional producers of IL-40 in both FACS and IF analysis. The ELISA test also showed a significant increase of serum IL-40 concentration in pSS patients (p value = 0.0190), compared to controls.Conclusion:Our preliminary results suggest that IL-40 may play a role in the pathogenesis of pSS and pSS-associated NHL. To the best of our knowledge, this is the first demonstration of the overexpression of this cytokine in salivary gland tissue and sera in pSS. Moreover, we demonstrated that IL-40 is produced by several cellular types, such as T cells and macrophages, and is not exclusively released by B cells. Further studies are necessary to clarify IL-40 pathways and functions in order to unravel IL-40 possible role in pSS development.References:[1]Mariette X, Criswell LA. Primary Sjogren’s Syndrome. N Engl J Med. 2018;379(1):97.[2]Catalan-Dibene J, Vazquez MI, Luu VP, Nuccio SP, Karimzadeh A, Kastenschmidt JM, et al. Identification of IL-40, a Novel B Cell-Associated Cytokine. J Immunol. 2017;199(9):3326-35.Figure 1.IL-40 overexpression in pSS and pSS-associated lymphoma A, Salivary gland biopsies stained for IL-40 showing a marked increase in IL-40 expression in presence of higher focus score. B, Parotid gland specimens of pSS-associated lymphoma showing intense staining for IL-40.Disclosure of Interests:Chiara Rizzo: None declared, Marianna Lo Pizzo: None declared, Leila Mohammadnezhad: None declared, Vincenzo Luca Lentini: None declared, Diana Di Liberto: None declared, Giulia Grasso: None declared, Piero Ruscitti Consultant of: Pfizer, Novartis, Celgene, Abbvie, Roche, Lilly, Rorberto Giacomelli Consultant of: Pfizer, Novartis, Celgene, Abbvie, Roche, Lilly, francesco ciccia Consultant of: Pfizer, Novartis, Celgene, Abbvie, Roche, Lilly, Giuliana Guggino Consultant of: Pfizer, Novartis, Celgene, Abbvie, Roche, Lilly

Inflammatory bowel disease (IBD) is an increasingly urgent medical problem that strongly impairs quality of life for patients. A global rise in incidence has been observed over the last few decades, with the highest incidence rates recorded in North America and Europe. Still, an increased incidence has been reported in the last ten years in newly industrialized countries in Asia, including China and India, both with more than one billion inhabitants. These data underline that IBD is an urgent global health problem. In addition, it is estimated that between 20% and 30% of IBD patients will develop colorectal cancer (CRC) within their lifetime and CRC mortality is approximately 50% amongst IBD patients. Although the exact etiology of IBD is still being defined, it is thought to be due to a complex interaction between many factors, including defects in the innate and adaptive immune system; microbial dysbiosis, i.e., abnormal levels of, or abnormal response to, the gastrointestinal microbiome; a genetic predisposition; and several environmental factors. At present, however, it is not fully understood which of these factors are the initiators of inflammation and which are compounders. The purpose of this review is to analyze the complex balance that exists between these elements to maintain intestinal homeostasis and prevent IBD or limit adverse effects on people’s health.

The immune system, smartly and surprisingly, saves the exposure of a particular pathogen in its memory and reacts to the pathogen very rapidly, preventing serious diseases.Immunologists have long been fascinated by understanding the ability to recall and respond faster and more vigorously to a pathogen, known as “memory”.T-cell populations can be better described by using more sophisticated techniques to define phenotype, transcriptional and epigenetic signatures and metabolic pathways (single-cell resolution), which uncovered the heterogeneity of the memory T-compartment. Phenotype, effector functions, maintenance, and metabolic pathways help identify these different subsets. Here, we examine recent developments in the characterization of the heterogeneity of the memory T cell compartment. In particular, we focus on the emerging role of CD8+ TRM and TSCM cells, providing evidence on how their immunometabolism or modulation can play a vital role in their generation and maintenance in chronic conditions such as infections or autoimmune diseases.