Abstract
ETV6::RUNX1, the most common oncogenic fusion gene in pediatric B-cell precursor acute lymphoblastic leukemia, is typically acquired in utero and establishes a preleukemic state with low frequent ETV6::RUNX1+ early hematopoietic progenitor clones that may persist for years. Secondary mutations are necessary for leukemogenesis and are likely triggered by dysregulated immune responses. To understand why ETV6::RUNX1+ preleukemic cells evade immune-mediated clearance, we compared the immune environment of newborns with or without ETV6::RUNX1+ (E::R+) clones. DNA-based screening of 1400 cord blood samples identified 102 preleukemic E::R+ (7.28%) and 1298 control E::R– newborns. Immunophenotyping indicated a skewing towards NK cells in E::R+ cord blood, with increased activating receptor NKG2D expression and elevated numbers of cytotoxic CD16+CD56dim NK effector cells. Nevertheless, similar killing activities were observed in co-culture of E::R+ and E::R– cord blood-derived total nucleated cells against K562 target cells. Furthermore, no significant differences in cytotoxic potential were uncovered using single-cell RNA sequencing. Interestingly, plasma proteomics revealed elevated levels of CXCL2, EGF, ANGPT1, CTF1, CD200 and IL13 in the preleukemic immune environment implying an inflammatory and potentially protective state, while CX3CL1 was elevated in children who had developed E::R+ leukemia. Short-term CX3CL1-CX3CR1 inhibition reduced NK cytotoxicity and GZMB release, indicating a role in NK effector function, whereas chronically elevated CX3CL1, as seen in children with E::R+ leukemia, lead to reduced NKG2D and GZMB. Our data suggest that preleukemia is characterized by inflammatory remodelling that may promote NK-cell dysfunction and impaired immunosurveillance.
Authors and Affiliations
Eleni Vasileiou¹˒²˒³˒⁴, Nadine Rüchel¹˒², Tiina Tuononen⁵, Hazel Sahin²˒³˒⁴, Rigveda Bhave¹˒²˒⁶, Vera H. Jepsen¹˒², Julian Schliehe-Diecks¹˒², Sanil Bhatia¹˒², Ulrike Strube³, Katharina L. Gössling¹, Susanne V. Schmidt³, Merja Heinäniemi⁵, Gesine Kogler⁶, Arndt Borkhardt¹˒²˒⁷, Ute Fischer¹˒²˒⁷, Aleksandra A. Pandyra¹˒²˒³˒⁴
¹ Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
² Center for Integrated Oncology Aachen Bonn Cologne Düsseldorf (CIO ABCD), Düsseldorf, Germany
³ Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
⁴ German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
⁵ Institute of Biomedicine, School of Medicine, University of Eastern Finland, Kuopio, Finland
⁶ Institute for Transplantation Diagnostics and Cell Therapeutics, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
⁷ DKTK Partner Site Essen-Düsseldorf, Germany