The mechanisms responsible for the evolution of steatosis toward non-alcoholic steato-hepatitis (NASH) and fibrosis are not completely defined. This study evaluated the role of CD4⁺ T-helper (Th) cells in this process. We analyzed the infiltration of different subsets of CD4⁺Th cells in C57BL/6 mice fed with a methione-choline deficient (MCD) diet, which is a model reproducing all phases of human NASH progression. There was an increase in Th17 cells at the beginning of NASH development and at the NASH/fibrosis transition, whereas levels of Th22 cells peaked between the first and the second expansion of Th17 cells. An increase in the production of IL-6, TNFa, TGFβ and CCL20 accompanied the changes in Th17/22 cells. Livers of IL-17^-/^- mice were protected from NASH development and characterized by an extensive infiltration of Th22 cells. In vitro , IL-17 exacerbated the JNK-dependent mouse hepatocyte lipotoxicity induced by palmitate. IL-22 prevented lipotoxicity through phosphatidylinositol-3-kinase-mediated inhibition of JNK but did not play a protective role in the presence of IL-17, which upregulated the phosphatidylinositol-3-kinase/Akt inhibitor PTEN. Consistently, livers of IL-17^-/^- mice fed with the MCD diet displayed decreased activation of JNK, reduced expression of PTEN and increased phosphorylation of Akt compared to livers of wild type mice. Hepatic infiltration of Th17 cells is critical for NASH initiation and development of fibrosis in mice, and reflects an infiltration of Th22 cells. Th22 cells are protective in NASH, but only in the absence of IL-17. These data strongly support the potentiality of clinical applications of IL-17 inhibitors that can prevent NASH by both abolishing the lipotoxic action of IL-17 and allowing IL-22-mediated protection.

Pancreatic ductal adenocarcinoma (PDA) is an aggressive tumor, and patients typically present with late-stage disease; rates of 5-year survival after pancreaticoduodenectomy are low. Antibodies against α-enolase (ENO1), a glycolytic enzyme, are detected in more than 60% of patients with PDA, and ENO1-specific T cells inhibit the growth of human pancreatic xenograft tumors in mice. We investigated whether an ENO1 DNA vaccine elicits antitumor immune responses and prolongs survival of mice that spontaneously develop autochthonous, lethal pancreatic carcinomas. We injected and electroporated a plasmid encoding ENO1 (or a control plasmid) into Kras(G12D)/Cre (KC) mice and Kras(G12D)/Trp53(R172H)/Cre (KPC) mice at 4 weeks of age (when pancreatic intraepithelial lesions are histologically evident). Antitumor humoral and cellular responses were analyzed by histology, immunohistochemistry, enzyme-linked immunosorbent assays, flow cytometry, and enzyme-linked immunosorbent spot and cytotoxicity assays. Survival was analyzed by Kaplan-Meier analysis. The ENO1 vaccine induced antibody and a cellular response and increased survival times by a median of 138 days in KC mice and 42 days in KPC mice compared with mice given the control vector. On histologic analysis, the vaccine appeared to slow tumor progression. The vaccinated mice had increased serum levels of anti-ENO1 immunoglobulin G, which bound the surface of carcinoma cells and induced complement-dependent cytotoxicity. ENO1 vaccination reduced numbers of myeloid-derived suppressor cells and T-regulatory cells and increased T-helper 1 and 17 responses. In a genetic model of pancreatic carcinoma, vaccination with ENO1 DNA elicits humoral and cellular immune responses against tumors, delays tumor progression, and significantly extends survival. This vaccination strategy might be developed as a neoadjuvant therapy for patients with PDA.

Pancreatic Ductal Adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by rapid progression, invasiveness and resistance to treatment. We have previously demonstrated that most PDAC patients have circulating antibodies against the glycolytic enzyme alpha-enolase (ENO1), which correlates with a better response to therapy and survival. ENO1 is a metabolic enzyme, also expressed on the cell surface where it acts as a plasminogen receptor. ENO1 play a crucial role in cell invasion and metastasis by promoting plasminogen activation into plasmin, a serine-protease involved in extracellular matrix degradation. The aim of this study was to investigate the role of ENO1 in PDAC cell invasion. We observed that ENO1 was expressed on the cell surface of most PDAC cell lines. Mouse anti-human ENO1 monoclonal antibodies inhibited plasminogen-dependent invasion of human PDAC cells, and their metastatic spreading in immunosuppressed mice was inhibited. Notably, a single administration of Adeno-Associated Virus (AAV)-expressing cDNA coding for 72/1 anti-ENO1 mAb reduced the number of lung metastases in immunosuppressed mice injected with PDAC cells. Overall, these data indicate that ENO1 is involved in PDAC cell invasion, and that administration of an anti-ENO1 mAb can be exploited as a novel therapeutic option to increase the survival of metastatic PDAC patients.

Th1 and Th17 cells have been considered as effectors in mouse EAE and in the human counterpart, MS. Recently, IL-22, a Th17-related, proinflammatory cytokine, has been associated with a new Th cell subset, defined as Th22, involved in chronic inflammatory conditions, such as psoriasis; the role of IL-22 in MS has not yet been elucidated. Here, we report that similar to Th17 cells, the number of Th22 cells increased in the PB and the CSF of RR MS patients, especially during the active phases of the disease. However, as opposed to Th17 cells, the expansion of Th22 cells occurred before the active phases of the disease. Th22 cells were found to be specific for the autoantigen MBP and also expressed high levels of CCR6 and T-bet, as for Th17 cells, indicating that Th22 self-reactive cells could have CNS-homing properties and be pathogenic in active RRMS patients. Conversely to Th17 cells, Th22 cells displayed lower levels of IFNAR1 and were insensitive to IFN-β inhibition. These data suggest that expansion of Th22 cells in MS could be one of the factors that critically influence resistance to IFN-β therapy.

Objective: To analyze changes in T-helper (Th) subsets, T-regulatory (Treg) cell percentages and function, and mRNA levels of immunologically relevant molecules during a 24-month follow-up after alemtuzumab treatment in patients with relapsing-remitting multiple sclerosis (RRMS). Methods: Multicenter follow-up of 29 alemtuzumab-treated patients with RRMS in the Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis (CARE-MS) I and CARE-MS II trials. Peripheral blood (PB) samples were obtained at months 0, 6, 12, 18, and 24. We evaluated (1) mRNA levels of 26 immunologic molecules (cytokines, chemokines, chemokine receptors, and transcriptional factors); (2) Th1, Th17, and Treg cell percentages; and (3) myelin basic protein (MBP)–specific Treg suppressor activity. Results: We observed 12 relapses in 9 patients. mRNA levels of the anti-inflammatory cytokines interleukin (IL)–10, IL-27, and transforming growth factor–β persistently increased whereas those of proinflammatory molecules related to the Th1 or Th17 subsets persistently decreased after alemtuzumab administration throughout the follow-up period. PB CD4+ cell percentage remained significantly lower than baseline while that of Th1 and Th17 cells did not significantly change. A significant increase in Treg cell percentage was observed at month 24 and was accompanied by an increase in Treg cell suppressive activity against MBP-specific Th1 and Th17 cells. Conclusions: The long-lasting therapeutic benefit of alemtuzumab in RRMS may involve a shift in the cytokine balance towards inhibition of inflammation associated with a reconstitution of the PB CD4+ T-cell subsets that includes expansion of Treg cells with increased suppressive function.

Natalizumab is a monoclonal antibody highly effective in the treatment of relapsing remitting multiple sclerosis (RRMS) patients. Despite its effectiveness, there are growing concerns regarding the risk of progressive multifocal leukoencephalopathy (PML), a brain infection caused by John Cunningham virus (JCV), particularly after 24 doses and in patients who previously received immunosuppressive drugs. Long-term natalizumab treated, immunosuppressive-pretreated, and JCV antibody-positive patients are asked to rediscuss natalizumab continuation or withdrawal after 24 doses. Until now, there has not been a clear strategy that should be followed to avoid PML risk and in parallel reduce clinical and radiological rebound activity. In this review, we analyzed the results of clinical trials and case reports in relation to the following situations: natalizumab continuation, natalizumab discontinuation followed by full therapeutic suspension or switch to other first or second line MS treatments. Quitting all MS treatment after natalizumab increases MS activity occurrence. The results regarding the therapeutic switch are not homogeneous, so at the moment there are no established guidelines regarding natalizumab treatment after 24 administrations; the choice is currently based on the professional experience of the neurologist, and on patients’ clinical features and preferences.