Targeting Interleukin-2-Inducible T-Cell Kinase (ITK) Differentiates GVL and GVHD in Allo-HSCT

Abstract

Allogeneic hematopoietic stem cell transplantation is a potentially curative procedure for many malignant diseases. Donor T cells prevent disease recurrence via graft-versus-leukemia (GVL) effect. Donor T cells also contribute to graft-versus-host disease (GVHD), a debilitating and potentially fatal complication. Novel treatment strategies are needed which allow preservation of GVL effects without causing GVHD. Using murine models, we show that targeting IL-2-inducible T cell kinase (ITK) in donor T cells reduces GVHD while preserving GVL effects. Both CD8+ and CD4+ donor T cells from Itk-/- mice produce less inflammatory cytokines and show decrease migration to GVHD target organs such as the liver and small intestine, while maintaining GVL efficacy against primary B-cell acute lymphoblastic leukemia (B-ALL). Itk-/- T cells exhibit reduced expression of IRF4 and decreased JAK/STAT signaling activity but upregulating expression of Eomesodermin (Eomes) and preserve cytotoxicity, necessary for GVL effect. Transcriptome analysis indicates that ITK signaling controls chemokine receptor expression during alloactivation, which in turn affects the ability of donor T cells to migrate to GVHD target organs. Our data suggest that inhibiting ITK could be a therapeutic strategy to reduce GVHD while preserving the beneficial GVL effects following allo-HSCT treatment.

Targeting SLP76:ITK interaction separates GVHD from GVL in allo-HSCT

“…We recently showed that ITK is differentially required for GVHD and GVL ( Mammadli et al., 2020 ). Therefore, we tested whether this distinction depends on the interaction of ITK with SLP76.…”

“…The SLP76 Y145 and ITK interaction is involved in signaling pathways that lead to cytokine production by T cell populations, as well as in regulating the development of a distinct, innate-type cytokine-producing T cell population in the thymus ( Atherly et al., 2006 ), referred to as innate memory phenotype (IMP) T cells. CD4 + and CD8 + T cells from SLP76Y145FKI mice express significantly higher CD122, CD44, and Eomes compared to T cells from WT mice on a basal, unstimulated level ( Mammadli et al., 2020 ). Since the activation, expansion, cytokine production, and migration of alloreactive donor T cells to target organs are hallmarks of GVHD ( Henden and Hill, 2015 ; Lynch Kelly et al., 2015 ), efforts to understand signaling pathways that allow separation from GVL will enable us to develop target-specific therapeutic modulators.…”

“…CD4 + and CD8 + T cells with CD44 high (CD44 hi ) are considered antigen-experienced and activated cells. Both CD4 + and CD8 + T cells from SLP76Y145F- and ITK-deficient mice express a higher proportion of cells with CD44hi and CD122hi ( Mammadli et al., 2020 ). Both CD4 + and CD8 + T cells with CD44 hi and CD122 hi from SLP76Y145FKI- and ITK-deficient mice arise in the thymus during development, unlike memory CD44 hi CD4 + and CD8 + T cells that mainly arise in the periphery of WT mice in response to foreign antigens or because of homeostatic proliferation ( Mammadli et al., 2020 ).…”

“…Both CD4 + and CD8 + T cells from SLP76Y145F- and ITK-deficient mice express a higher proportion of cells with CD44hi and CD122hi ( Mammadli et al., 2020 ). Both CD4 + and CD8 + T cells with CD44 hi and CD122 hi from SLP76Y145FKI- and ITK-deficient mice arise in the thymus during development, unlike memory CD44 hi CD4 + and CD8 + T cells that mainly arise in the periphery of WT mice in response to foreign antigens or because of homeostatic proliferation ( Mammadli et al., 2020 ). Experimental studies in CD44 hi and CD44 lo cells arising in the periphery of WT mice show conflicting results ( Dutt et al., 2011 ; Zheng et al., 2009 ; Loschi et al., 2015 ; Anderson, 2003 ; Huang et al., 2019 ).…”

“…In this report, we show that WT CD8 + CD44 lo T cells induce severe GVHD, and that while WT CD8 + CD44 hi T cells induce less GVHD, as has been reported, they eventually cause GVHD ( Zhang et al., 2005 ; Huang et al., 2019 ). In contrast, SLP76Y145FKI CD8 + CD44 lo T cells are much less likely to induce GVHD, and SLP76Y145FKI CD8 + CD44 hi T cells do not cause GVHD but maintain a significant GVL effect ( Mammadli et al., 2020 ). Both CD8 + and CD4 + SLP76Y145FKI T cells exhibit attenuated TCR signaling and an IMP as indicated by expression of high levels of CD44 and CD122, and CD8 + SLP76Y145FKI T cells also express higher levels of the transcription factor Eomes ( Huang et al., 2014 ; Carty et al., 2014 ).…”