Published in:
Open Access
01-10-2008 | Original Article
IL-21 induces in vivo immune activation of NK cells and CD8+ T cells in patients with metastatic melanoma and renal cell carcinoma
Authors:
Klaus Stensgaard Frederiksen, Dorthe Lundsgaard, Jeremy A. Freeman, Steven D. Hughes, Thomas L. Holm, Birte K. Skrumsager, Andreas Petri, Lasse T. Hansen, Grant A. McArthur, Ian D. Davis, Kresten Skak
Published in:
Cancer Immunology, Immunotherapy
|
Issue 10/2008
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Abstract
Purpose
Human interleukin-21 (IL-21) is a class I cytokine previously reported in clinical studies on immune responsive cancers. Here we report the effects of systemic IL-21 therapy on the immune system in two phase 1 trials with this novel cytokine.
Experimental design
Recombinant IL-21 was administered by intravenous bolus injection at dose levels from 1 to 100 μg/kg using two planned treatment regimens: thrice weekly for 6 weeks (3/week); or once daily for five consecutive days followed by nine dose-free days (5 + 9). The following biomarkers were studied in peripheral blood mononuclear cells (PBMC) during treatment: phosphorylation of STAT3, alterations in the composition of leukocyte subsets, ex vivo cytotoxicity, expression of effector molecules in enriched CD8+ T cells and CD56+ NK cells by quantitative RT-PCR, and gene array profiling of CD8+ T cells.
Results
Effects of IL-21 were observed at all dose levels. In the 5 + 9 regimen IL-21 induced a dose dependent decrease in circulating NK cells and T cells followed by a return to baseline in resting periods. In both CD8+ T cells and CD56+ NK cells we found up-regulation of perforin and granzyme B mRNA. In addition, full transcriptome analysis of CD8+ T cells displayed changes in several transcripts associated with increased cell cycle progression, cellular motility, and immune activation. Finally, cytotoxicity assays showed that IL-21 enhanced the ability of NK cells to kill sensitive targets ex vivo.
Conclusions
IL-21 was biologically active at all dose levels administered with evidence of in vivo NK cell and CD8+ T cell activation.