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ISRN Immunology
Volume 2012 (2012), Article ID 208903, 6 pages
http://dx.doi.org/10.5402/2012/208903
Review Article

Immune Escape Mechanisms in Diffuse Large B-Cell Lymphoma

1Department of Hemato-Oncology, Faculty of Medicine and Dentistry, Palacky University Olomouc, I. P. Pavlova 6, Olomouc 77520, Czech Republic
2Department of Clinical and Molecular Pathology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic

Received 5 November 2012; Accepted 13 December 2012

Academic Editors: V. Boussiotis and H. Dong

Copyright © 2012 V. Procházka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Diffuse large B-cell lymphoma (DLBCL) is the most frequent subtype of non-Hodgkin lymphomas in Western countries. Implementation of immunotherapy using monoclonal antibodies to therapeutic protocols has led to dramatic improvements in overall survival. DLBCL became a model of a successful immunochemotherapy concept. Despite this fact, there is still a proportion of patients who do not respond to or relapse early after treatment. Growing evidence suggests that host antitumor immunity is suppressed by lymphoma cells in many ways. First, host cytotoxic T cells are directly suppressed by interaction with programmed cell death (PD) ligand on lymphoma cell surface and a similar mechanism enhances the activity of suppressive regulatory T cells (Tregs). Second, tumor cells escape host cytotoxic cells due to lower immunogenicity caused by reduced expression of HLA antigens. Both mechanisms have an origin in primary genetic events in lymphomagenesis. Rearrangement of MHC class II transcriptional activator (CIITA) gene and amplification of Janus kinase (JAK2) gene lead to enhanced expression of PD ligands 1 and 2, higher proliferation activity, and lower expression of HLA. This paper summarizes current knowledge about clinically relevant immune escape mechanisms in DLBCL.