Interferon-alfa2 Treatment of Patients with Polycythemia Vera and Related Neoplasms Influences Deregulated Inflammation and Immune Genes in Polycythemia Vera and Allied Neoplasms

Introduction: The Philadelphia-negative myeloproliferative neoplasms are associated with deregulation of inflammation and immune genes implying a gene signature of a chronic inflammatory state and immune deregulation. Several studies have demonstrated interferon-alpha2 (IFN) to be highly efficacious in normalizing elevated blood cell counts and in inducing molecular remissions as well. Using whole blood gene expression, we herein for the first time show that IFN profoundly influences the deregulated inflammation- and immune genes giving rise to a gene signature indicative of decreased inflammation and improved regulation of immune genes during IFN treatment.

Material and Methods: Gene expression microarray studies have been performed on eight patients with ET, 21 patients with PV, and 4 patients with PMF. All patients received treatment with IFN, in the large majority in a dosage ranging from 45-90 ug x 1 sc/week. Gene expression profiles were generated using Affymetrix HG-U133 2.0 Plus microarrays recognizing 54.675 probe sets (38.500 genes). Total RNA was purified from whole-blood and amplified to biotin-labeled aRNA and hybridized to microarray chips.

Results: We identified 6261, 10,008, and 2828 probe sets to be significantly differentially expressed in ET, PV, and PMF, respectively, during treatment with IFN (pvalue <0.05). Previously, we have found 123 inflammation and immune genes to be significantly deregulated in patients with MPN compared to healthy subjects. Here, we extend the gene list with 19 inflammation and immune genes, recently shown to be involved in other cancer. Several of these 142 genes were significantly deregulated during IFN therapy. In response to treatment with IFN, 20 genes were upregulated in ET including CX3CR1, CCL2, CCR1, CCR5, CCR7, HGF, HLA-G, IL1RN, IL10RA, PTX3, TP53, and TGFB1, and 6 genes were downregulated including MAPK1, ORM1, and IL1R1. In patients with PV, ABCF1, CCL2, CCR1, CCR2, CCR5, CCR7, CD3E, CD3G, CD4, CD40LG, CX3CR1, HLA-G, IL1RN, IL8, IL10RA, PTX3, TP53, TGFB1, TNFAIP3 were among the 32 upregulated genes, and BCL6, IL1R1, MAPK1, and ORM1 were among the 10 downregulated genes. During treatment with IFN, 11 genes were upregulated in PMF including CCL2, CCR1, CCR5, CX3CR1, IL1RN, PTX3, and TNFAIP3 and 5 genes were downregulated including BCL6, IL1R1, and ORM1.

Discussion and Conclusion: Interferon-alpha2 is increasingly been recognized as a highly efficacious and promising agent in the treatment of MPNs. During recent years several studies have shown that chronic inflammation and immunoderegulation is likely involved in the pathogenesis of MPNs. Thus, elevated blood levels of circulating inflammatory cytokines have been recorded, some even having a prognostic impact and predicting imminent leukemic transformation. Chronic inflammation impairs IFN-signaling and likely therefore the efficacy of IFN in MPNs, although this notion has to be confirmed in MPNs. Immunoderegulation with defective immune surveillance may contribute to the increased risk of second cancers both before and after the MPN-diagnosis. Accordingly, there is an urgent need to explore if IFN might be able to restore deregulated inflammation and immune genes in MPNs. In this study, we have convincingly shown that several genes of significance for inflammation and immune surveillance are positively influenced by IFN treatment implying a significant downregulation of upregulated inflammation genes (e.g. BCL6, IL1R1, MAPK1, ORM1,) and a significant upregulation of downregulated immune genes (e.g. ABCF1, CCR2, CCR5, CCR7, CD3D, CD3E, CD3G, CD4, CD40LG, CXCR1, HLA-G, IL10RA, IL8, TFGB1, TNFAIP3, and TP53). Recently, we have shown significant downregulation of CCR9, CREB1, FAS, LSP1, LTB, NFKB1, SCYE1, SELPG, STAT3, and TNFAIP8L1, and significant upregulation of CCL25, CCL7, CSF3, CXCL9, FOXP3, IL17A, IL17C, IL1F10, IL1F6, IL22, IL4, IL5, ITGB3, in ET, PV, and PMF compared to controls. These genes were no longer significantly deregulated during IFN-treatment. In conclusion, our results have added highly important information on the impact of IFN upon deregulated inflammation and immune genes in MPNs, thereby substantiating the beneficial effects of IFN and its major role as the cornerstone in the future treatment of MPNs. Our study opens the avenue for larger studies exploring the genomic landscape during treatment of patients with MPNs.