Adaptive Immunity in Autoimmune Hepatitis

TY - JOUR

T1 - Adaptive Immunity in Autoimmune Hepatitis

AU - Longhi, Maria Serena

AU - Ma, Yun

AU - Mieli-Vergani, Giorgina

AU - Vergani, Diego

PY - 2010/5

Y1 - 2010/5

N2 - The histological lesion of interface hepatitis, with its dense portal cell infiltrate consisting of lymphocytes, monocytes/macrophages and plasma cells, was the first to suggest an autoaggressive cellular immune attack in the pathogenesis of autoimmune hepatitis (AIH). Immunohistochemical studies, focused on the phenotype of inflammatory cells infiltrating the liver parenchyma, have shown a predominance of alpha beta-T cells. Amongst these cells, the majority have been CD4 helper/inducers, while a sizeable minority have consisted of CD8 cytotoxic/suppressors. Lymphocytes on non-T cell lineage included natural killer cells, monocytes/macrophages and B lymphocytes. For autoimmunity to arise, the self-antigenic peptide, embraced by an human leukocyte antigen (HLA) class II molecule, must be presented to an uncommitted T helper (T(H)0) lymphocyte by professional antigen-presenting cells. Once activated and according to the presence in the milieu of interleukin 12 (IL-12) or IL-4, T(H)0 lymphocytes can differentiate into T H 1 cells, which are pivotal to macrophage activation; enhance HLA class I expression, rendering liver cells vulnerable to CD8 T-cell attack; and induce HLA class II expression on hepatocytes; or they can differentiate into T H 2 cells, which produce IL-4, IL-10 and IL-13, cytokines favouring autoantibody production by B lymphocytes. Autoantigen recognition is tightly controlled by regulatory mechanisms, such as those exerted by CD4+CD25(high) regulatory T cells. Numerical and functional regulatory T cell impairment characterises AIH and permits the perpetuation of effector immune responses with ensuing persistent liver destruction. Advances in the study of autoreactive T cells stem mostly from AIH type 2, where the main autoantigen, cytochrome P450IID6 (CYP2D6), is known to enable characterisation of antigen-specific immune responses. Copyright (C) 2010 S. Karger AG, Basel

AB - The histological lesion of interface hepatitis, with its dense portal cell infiltrate consisting of lymphocytes, monocytes/macrophages and plasma cells, was the first to suggest an autoaggressive cellular immune attack in the pathogenesis of autoimmune hepatitis (AIH). Immunohistochemical studies, focused on the phenotype of inflammatory cells infiltrating the liver parenchyma, have shown a predominance of alpha beta-T cells. Amongst these cells, the majority have been CD4 helper/inducers, while a sizeable minority have consisted of CD8 cytotoxic/suppressors. Lymphocytes on non-T cell lineage included natural killer cells, monocytes/macrophages and B lymphocytes. For autoimmunity to arise, the self-antigenic peptide, embraced by an human leukocyte antigen (HLA) class II molecule, must be presented to an uncommitted T helper (T(H)0) lymphocyte by professional antigen-presenting cells. Once activated and according to the presence in the milieu of interleukin 12 (IL-12) or IL-4, T(H)0 lymphocytes can differentiate into T H 1 cells, which are pivotal to macrophage activation; enhance HLA class I expression, rendering liver cells vulnerable to CD8 T-cell attack; and induce HLA class II expression on hepatocytes; or they can differentiate into T H 2 cells, which produce IL-4, IL-10 and IL-13, cytokines favouring autoantibody production by B lymphocytes. Autoantigen recognition is tightly controlled by regulatory mechanisms, such as those exerted by CD4+CD25(high) regulatory T cells. Numerical and functional regulatory T cell impairment characterises AIH and permits the perpetuation of effector immune responses with ensuing persistent liver destruction. Advances in the study of autoreactive T cells stem mostly from AIH type 2, where the main autoantigen, cytochrome P450IID6 (CYP2D6), is known to enable characterisation of antigen-specific immune responses. Copyright (C) 2010 S. Karger AG, Basel

UR - http://www.scopus.com/inward/record.url?scp=77952571694&partnerID=8YFLogxK

U2 - 10.1159/000282066

DO - 10.1159/000282066

M3 - Conference paper

VL - 28

SP - 63

EP - 69

JO - Digestive Diseases

JF - Digestive Diseases

IS - 1

T2 - Falk Workshop on Immunology and Liver Disease/Falk Symposium 171 on Liver and Metabolic Syndrome

Y2 - 15 October 2009 through 18 October 2009

ER -