Allogeneic innate lymphocytes such as Vγ9Vδ2 T cells are attractive candidates for cancer immunotherapy as they provide MHC-unrestricted antitumor activity without clinical evidence for inducing graft-versus-host disease (GvHD). However, current cellular immunotherapy approaches lack predictive biomarkers identifying patient cohorts most susceptible to immune attack. For this purpose we performed a comprehensive analysis of clinical, genetic, metabolic, and immunophenotypic features of 19 primary acute myeloid leukemia (AML) samples and correlated these factors with AML blast recognition by allogeneic Vγ9Vδ2 T cells. We show that 36% of primary AML samples were intrinsically susceptible to allogeneic Vγ9Vδ2 T cells. Among several evaluated features, only UL-16 binding protein 1 (ULBP1) expression (P<0.01) determines intrinsic AML susceptibility to allogeneic Vγ9Vδ2 T cells. Within the intrinsically resistant AML samples, pretreatment of AML blasts with nitrogen-containing bisphosphonates (NBP) significantly induced Vγ9Vδ2 T-cell cytotoxicity in 50% of AML samples, whereas 50% of AML samples were consistently refractory to γδ T-cell cytolysis. Activity of the mevalonate pathway (P<0.05) and myelomonocytic differentiation of AML (P<0.05) correlated with sensitivity of primary AML samples toward NBP pretreatment. In conclusion, this study identifies subsets of AML patients most likely to benefit from allogeneic Vγ9Vδ2 T-cell-mediated immunotherapy.

Background: Autologous stem cell transplantation is considered a standard of care treatment in eligible patients with multiple myeloma, but puts the patient at high risk for infections and bleeding complications. Acquired von-Willebrand's disease (AVWD) and acquired platelet dysfunction are rare bleeding disorders that are associated with lymphoproliferative disorders such as multiple myeloma. Patients with acquired bleeding disorders who are planned for ASCT to treat the underlying condition are considered at highest risk for bleeding complications, and optimal treatment strategies are not known. Materials and Methods: We summarized the diagnostic and therapeutic approach to a patient affected by AVWD and acquired platelet disorder related to multiple myeloma. The patient who was planned for ASCT presented with moderate to severe bleeding symptoms. Results: Acute bleeding episodes were successfully controlled and prevented during induction and consolidation therapy with immunoglobulins, whereas replacement of plasma-derived VW factor showed no clinical improvement. High-dose melphalan-based consolidation therapy supported with autologous stem-cell transplantation led to an immediate and sustainable rise of von-Willebrand antigen and activity and a subsequent normalization of platelet aggregation activity. After a follow-up of 40 weeks, the patient maintained normalized VW levels and platelet aggregation capacity. There were no further signs or symptoms of bleeding. Conclusion: This case report highlights the necessity for combined supportive and causal treatment in patients with AVWD and paraproteinemic PD. High-dose melphalan with autologous stem cell support may function as a treatment option in patients with myeloma-related AVWD.

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