Previous studies reported associations of IFITM3 SNP rs12252 with severe influenza, but evidence of association and the mechanism of risk remains controversial. We prioritized SNPs in IFITM3 based on putative biological function and identified rs34481144 in the 5′ UTR. We found evidence of a novel association of rs34481144 with severe influenza in three influenza-infected cohorts characterized by different levels of influenza illness severity. We determined the role of rs34481144 as an expression quantitative trait loci (eQTL) for IFITM3, with the risk allele associated with lower mRNA expression. The risk allele was found to have decreased IRF3 binding and increased CTCF binding in promoter-binding assays, and risk allele carriage diminished transcriptional correlations among neighboring genes, indicative of CTCF boundary activity. Furthermore, the risk allele disrupts a CpG site that undergoes differential methylation in CD8 T-cell subsets. Carriers of the risk allele had reduced CD8 T-cells in their airways during natural influenza infection, consistent with IFITM3 promoting airway CD8 T-cell accumulation, indicating that a critical function for IFITM3 may be to promote immune cell persistence at mucosal sites. Our study identifies a new regulator of IFITM3 expression that associates with CD8 T-cell levels in the airways and a spectrum of clinical outcomes.

Aging strongly promotes inflammation responses, which may predispose individuals after cancer therapies to lethal system toxicities and pathology that can be partially prevented by TNF blockade.

Compared to adults, infants suffer higher rates of hospitalization, severe clinical complications, and mortality due to influenza infection. We found that γδ T cells protected neonatal mice against mortality during influenza infection. γδ T cell deficiency did not alter viral clearance or interferon-γ production. Instead, neonatal influenza infection induced the accumulation of interleukin-17A (IL-17A)-producing γδ T cells, which was associated with IL-33 production by lung epithelial cells. Neonates lacking IL-17A-expressing γδ T cells or Il33 had higher mortality upon influenza infection. γδ T cells and IL-33 promoted lung infiltration of group 2 innate lymphoid cells and regulatory T cells, resulting in increased amphiregulin secretion and tissue repair. In influenza-infected children, IL-17A, IL-33, and amphiregulin expression were correlated, and increased IL-17A levels in nasal aspirates were associated with better clinical outcomes. Our results indicate that γδ T cells are required in influenza-infected neonates to initiate protective immunity and mediate lung homeostasis.

Purpose: Previous studies demonstrate that intratumoral CpG immunotherapy in combination with radiotherapy acts as an in-situ vaccine inducing antitumor immune responses capable of eradicating systemic disease. Unfortunately, most patients fail to respond. We hypothesized that immunotherapy can paradoxically upregulate immunosuppressive pathways, a phenomenon we term "rebound immune suppression," limiting clinical responses. We further hypothesized that the immunosuppressive enzyme indolamine-2,3-dioxygenase (IDO) is a mechanism of rebound immune suppression and that IDO blockade would improve immunotherapy efficacy.Experimental Design: We examined the efficacy and immunologic effects of a novel triple therapy consisting of local radiotherapy, intratumoral CpG, and systemic IDO blockade in murine models and a pilot canine clinical trial.Results: In murine models, we observed marked increase in intratumoral IDO expression after treatment with radiotherapy, CpG, or other immunotherapies. The addition of IDO blockade to radiotherapy þ CpG decreased IDO activity, reduced tumor growth, and reduced immunosuppressive factors, such as regulatory T cells in the tumor microenvironment. This triple combination induced systemic antitumor effects, decreasing metastases, and improving survival in a CD8þ T-cell-dependent manner. We evaluated this novel triple therapy in a canine clinical trial, because spontaneous canine malignancies closely reflect human cancer. Mirroring our mouse studies, the therapy was well tolerated, reduced intratumoral immunosuppression, and induced robust systemic antitumor effects. Conclusions: These results suggest that IDO maintains immune suppression in the tumor after therapy, and IDO blockade promotes a local antitumor immune response with systemic consequences. The efficacy and limited toxicity of this strategy are attractive for clinical translation. Clin Cancer Res; 22(17); 4328-40. Ó2016 AACR.

Blinatumomab, a bispecific antibody that directs CD3+ T cells to CD19+ tumor cells shows variable efficacy in B-progenitor acute lymphoblastic leukemia (B-ALL). To determine tumor-intrinsic and extrinsic determinants of response, we studied 44 adults with relapsed or refractory B-ALL (including two MRD positive) treated with blinatumomab using bulk tumor and single-cell sequencing. The overall response rate in patients with hematological disease was 55%, with a high response rate CRLF2-rearranged Ph-like ALL (12/16, 75%). Pretreatment samples of responders exhibited a tumor-intrinsic transcriptomic signature of heightened immune response. Multiple mechanisms resulted in loss of CD19 expression, including CD19 mutations, CD19 mutant allele-specific expression, low CD19 RNA expression and mutations in CD19 signaling complex member CD81. Low hypodiploid patients were prone to CD19 negative relapse due to aneuploidy-mediated loss of the non-mutated CD19 allele. Increased expression of a CD19 isoform with intra-exonic splicing of exon 2, CD19 ex2part, at baseline or during therapy was associated with treatment failure. These analyses demonstrate both tumor intrinsic and extrinsic factors influence blinatumomab response. We show that CD19 mutations are commonly detected in CD19-negative relapse during blinatumomab treatment. Identification of the CD19 ex2part splice variant represents a new biomarker predictive of failure to blinatumomab therapy.