IFN-α-based treatment of patients with chronic HCV show increased levels of cells with myeloid-derived suppressor cell phenotype and of IDO and NOS.

INTRODUCTION: Hepatitis C virus (HCV) infection causes chronic hepatitis, which is often associated with suppressed anti-HCV immune responses. We have recently reported accumulation of myeloid-derived suppressor cells (MDSCs) and suppressed immunity in cancer patients. AIM: The main aim of this study was to determine whether chronic HCV patients harbor high of MDSCs in general and in nonresponders to IFN-based therapy in particular as well as to analyze the immune suppressive molecules. METHODS: Peripheral blood samples withdrawn from 154 patients with chronic HCV infection and were categorized into responders and nonresponders based on viral titer upon IFN-α treatment. RESULTS: The relative and absolute numbers of MDSCs defined as Lin-/HLA-DR-/CD33+/CD11b+ increased in all HCV patients, where they were higher in nonresponders than in responders. Additionally, the levels of MDSCs after 4-6 months of treatment in responders were lower than during the course of treatment. The responders also showed higher levels of IL-2 coincided with increased numbers of dendritic cells (DCs), CD4+ and CD8+ T cells. The levels of total NOS and IDO were also higher in nonresponders as compared to responders and healthy controls, while the expression levels of CD3ζ was lower in responders as compared to nonresponders and healthy volunteers. CONCLUSION: Chronic HCV patients harbor high numbers of MDSCs, which are higher in nonresponders than in responders. The higher numbers of MDSCs associated with increases in the suppressing factors.

Acute inflammation induces immunomodulatory effects on myeloid cells associated with anti-tumor responses in a tumor mouse model.

Given the self nature of cancer, anti-tumor immune response is weak. As such, acute inflammation induced by microbial products can induce signals that result in initiation of an inflammatory cascade that helps activation of immune cells. We aimed to compare the nature and magnitude of acute inflammation induced by toll-like receptor ligands (TLRLs) on the tumor growth and the associated inflammatory immune responses. To induce acute inflammation in tumor-bearing host, CD1 mice were inoculated with intraperitoneal (i.p.) injection of Ehrlich ascites carcinoma (EAC) (5 × 10(5) cells/mouse), and then treated with i.p. injection on day 1, day 7 or days 1 + 7 with: (1) polyinosinic:polycytidylic (poly(I:C)) (TLR3L); (2) Poly-ICLC (clinical grade of TLR3L); (3) Bacillus Calmette Guerin (BCG) (coding for TLR9L); (4) Complete Freund's adjuvant (CFA) (coding for TLR9L); and (5) Incomplete Freund's Adjuvant (IFA). Treatment with poly(I:C), Poly-ICLC, BCG, CFA, or IFA induced anti-tumor activities as measured by 79.1%, 75.94%, 73.94%, 71.88% and 47.75% decreases, respectively in the total number of tumor cells collected 7 days after tumor challenge. Among the tested TLRLs, both poly(I:C) (TLR3L) and BCG (contain TLR9L) showed the highest anti-tumor effects as reflected by the decrease in the number of EAc cells. These effects were associated with a 2-fold increase in the numbers of inflammatory cells expressing the myeloid markers CD11b(+)Ly6G(+), CD11b(+)Ly6G(-), and CD11b(+)Ly6G(-). We concluded that Provision of the proper inflammatory signal with optimally defined magnitude and duration during tumor growth can induce inflammatory immune cells with potent anti-tumor responses without vaccination.