Characterization and role of intra-hepatic regulatory T cells in chronic hepatitis C pathogenesis.

Background & Aims: In chronic hepatitis C (CHC), HCV-specific T-cell responses are often dysfunctionnal. In vitro data point out that regulatory T cells (Treg) are able to suppress HCV-specific lymphocyte proliferation and cytokine secretion but their implication in this pathology is still debated.

Methods: Three complementary approaches were performed to investigate phenotype, frequency or localization of intra-hepatic Treg in treatment naïve CHC patients.

Fine characterization of intrahepatic NK cells expressing natural killer receptors in chronic hepatitis B and C.

Background/aims: The fate of intrahepatic NK cell subsets in the course of HCV and HBV infections is not clearly understood.

Methods: Blood and intrahepatic CD56(+) NK cell subsets (expressing NKG2A, CD158a,h or CD158b,j receptors) from HCV or HBV patients were quantified by flow cytometry and localized by immunohistochemistry in liver biopsies.

Results: A significant reduction in NK cell frequency and a quantitative imbalance between CD56(bright) and CD56(dim) subsets were observed in chronic HCV patients as compared to HBV patients, underlining that the inflammatory environment is not the only cause of these phenomena.

Control of experimental autoimmune encephalomyelitis by CD4+ suppressor T cells: peripheral versus in situ immunoregulation.

The pathogenesis of experimental autoimmune encephalomyelitis (EAE) can be efficiently kept under control by specialized subsets of CD4+ T lymphocytes able to negatively regulate the function of T cells with encephalitogenic potential. A number of observations support a role for such suppressor T cells in controlling early phases of disease development at the level of peripheral lymphoid organs but there is also evidence suggesting immunoregulation within the central nervous system (CNS) microenvironment itself. This review evaluates the sites of regulation based on available data from distinct experimental models.

Features and distribution of CD8 T cells with human leukocyte antigen class I-specific receptor expression in chronic hepatitis C.

Unlabelled: CD8(+) T cells represent a sizable component of the liver inflammatory infiltrate in chronic hepatitis C and are thought to contribute to immune-mediated tissue injury. Because chronic stimulation may promote the expression by CD8(+) T cells of distinct human leukocyte antigen class I-specific natural killer cell receptors (NKRs) susceptible to both inhibiting effector functions and promoting cell survival, we examined the distribution and characteristics of CD8(+) T cells with such receptors in chronic hepatitis C patients. NKR CD8(+) T cells were detectable in liver and peripheral blood from hepatitis C virus (HCV)-infected patients but were not major subsets.

Nitric oxide modulation of the immune response against cholera toxin-adjuvated ovalbumin administered by the intranasal route.

Here, we studied the effect of aminoguanidine (AG) treatment, a nitric oxide synthase (NOS)-2 inhibitor, during the immune response against intranasal administration of ovalbumin (OVA) mixed with cholera toxin (CT) in BALB/c mice. NOS-2 mRNA was detected by reverse transcription-PCR (RT-PCR) in samples of lungs and turbinates early post-inoculation of the antigen. Animals intranasally treated with AG, showed an increase in the levels of seric specific IgG and IgM.