Isolated Limb Perfusion With Melphalan Triggers Immune Activation in Melanoma Patients.

Junko Johansson,Anna Martner,Roberta Kiffin,Peter L Naredi,Per Lindnér,Roger Olofsson Bagge,Annica Andersson

doi:10.3389/fonc.2018.00570

Junko Johansson, Anna Martner + Show 5 more

Open Access

https://doi.org/10.3389/fonc.2018.00570

Copy DOI

Abstract

Hyperthermic isolated limb perfusion with melphalan (M-ILP) is a treatment option for melanoma patients with metastases confined to the limbs. This study aimed at defining the role of cellular immunity for the clinical response to M-ILP in melanoma patients. It was observed that patients with enhanced cytotoxic CD8+ T cell reactivity to common antigens (HCMV/EBV/influenza virus) prior to M-ILP were more likely to achieve a complete disappearance of macroscopic tumors (complete response). Following M-ILP treatment, the proportions of CD16+ intermediate and non-classical monocytes in peripheral blood were significantly enhanced along with induction of HLA-DR on CD4+ and CD8+ T cells. For further studies of the mechanism behind melphalan-induced immune activation an in vitro model, aiming at mimicking the clinical M-ILP protocol, was established, where PBMCs were co-cultured with melanoma cells, which had been pre-exposed to melphalan under mild hyperthermia. Upon exposure to melphalan, melanoma cells showed increased expression of immune-related markers including MHC class I and Hsp70. Moreover, when the melphalan-treated melanoma cells were co-cultured with PBMCs, this triggered an increased proportion of CD33+CD14+CD16++ non-classical monocytes among the PBMCs. Furthermore, the melphalan-treated melanoma cells stimulated the expansion of CD8+ T cells in the co-cultured PBMCs. These cells produced enhanced levels of IFN-γ and granzyme B and were capable of killing melanoma cells. To further verify an immunogenic role of melphalan, mice were vaccinated with melphalan-exposed murine melanoma cells. When challenged with live melanoma cells, vaccinated mice showed reduced tumor growth and enhanced infiltration of tumor-specific T cells into tumors. We conclude that melphalan-exposed melanoma cells trigger expansion of CD16+ monocytes and activate cytotoxic T cells and that these events may contribute to the antitumoral efficacy of M-ILP.

Highlights

For patients with recurrence of malignant melanoma, ∼5–10% develop lymphatic dissemination referred to as in-transit metastasis [1]
The results suggest that melphalan-exposed human melanoma cells trigger an activation of the immune system, as shown by expansion of CD16+ monocytic cells and activation of cytotoxic T cells and that these events may contribute to the clinical efficacy of M-ILP
M-ILP Is Associated With Expansion of CD16+ Monocytes in Melanoma Patients

Summary

Introduction

For patients with recurrence of malignant melanoma, ∼5–10% develop lymphatic dissemination referred to as in-transit metastasis [1]. Hyperthermic isolated limb perfusion with the alkylating agent melphalan (M-ILP) is a treatment option for in-transit melanoma metastases confined to a limb. During M-ILP, the affected limb is temporarily isolated from the systemic circulation and connected to a heart-lung machine. High doses of melphalan are perfused through the limb during 1 h under mild hyperthermia. During M-ILP, the concentrations of melphalan in the perfused tissue are at least 20 times higher than those achieved by the maximum tolerated dose after systemic administration [3, 4]. M-ILP induces a complete response (CR), defined as a total regression of melanoma lesions in 30–80% of the patients [5, 6]

Objectives

Methods

Results

Conclusion