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Case Reports in Medicine
Volume 2016, Article ID 9639585, 7 pages
http://dx.doi.org/10.1155/2016/9639585
Case Report

Diversification of Antitumour Immunity in a Patient with Metastatic Melanoma Treated with Ipilimumab and an IDO-Silenced Dendritic Cell Vaccine

1Department of Immunology, Oslo University Hospital, Montebello, 0310 Oslo, Norway
2Department of Clinical Cancer Research, Oslo University Hospital, Montebello, 0310 Oslo, Norway
3Department of Cell Therapy, Oslo University Hospital, Montebello, 0310 Oslo, Norway

Received 11 March 2016; Accepted 13 June 2016

Academic Editor: Jens Sondergaard

Copyright © 2016 Mouldy Sioud 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

Indoleamine 2,3-dioxygenase (IDO) expression in dendritic cells (DCs) inhibits T-cell activation and promotes T-cell differentiation into regulatory T-cells. Moreover, IDO expression promotes resistance to immunotherapies targeting immune checkpoints such as the cytotoxic T lymphocyte antigen-4 (CTLA-4). Here, a patient with metastatic melanoma pretreated with ipilimumab, an anti-CTLA-4 blocking antibody, was vaccinated with IDO-silenced DCs cotransfected with mRNA for survivin or hTERT tumour antigens. During vaccination, T-cell responses to survivin and hTERT tumour antigens were generated, and a certain degree of clinical benefit was achieved, with a significant reduction in lung, liver, and skin metastases, along with a better performance status. T-cell responses against MART-1 and NY-ESO-1 tumour antigens were also detected in the peripheral blood. The patient also mounted an antibody response to several melanoma proteins, indicating diversification of the antitumour immunity in this patient. The identification of such serum antibody-reacting proteins could facilitate the discovery of tumour neoantigens.