<i>IDH2</i> clonal hematopoiesis and IKAROS loss cooperate in a B-ALL subtype after lenalidomide therapy for multiple myeloma

J Johanna M. Horns (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) T Thomas Beder A Axel Künstner M Malwine J. Barz S Sonja Bendig (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) C Cecilia Bozzetti (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) G Guranda Chitadze (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) N Nikos Darzentas (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) K Katharina Iben (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) M Michaela Kotrova (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) J José I. Martin-Subero M Mayukh Mondal M Martin Neumann R Raúl F. Pérez A Aeint-Steffen Ströh (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany) W Wiebke Wessels L Lennart Lenk (10Department of Pediatrics I, University Hospital Schleswig-Holstein, Kiel, Germany) L Lars Velten B Boris Böll (13Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany) K Krischan Braitsch (14Department of Medicine III, TUM University Hospital, Technical University of Munich, Munich, Germany) V Veit Bücklein (Ludwig Maximilian University Hospital, Munich, Germany) J Johannes Duell (16Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, Germany) C Christoph Faul (17Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology and Rheumatology, University Hospital Tübingen, Tübingen, Germany) W Walter Fiedler M Maher Hanoun (19Department of Hematology and Stem Cell Transplantation, University Hospital Essen, Essen, Germany) S Snjezana Janjetovic (20Department of Hematology and Cell Therapy, Helios Klinikum Berlin-Buch, Berlin, Germany) F Felix Klingler (18Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany) S Stefan Knop (16Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, Germany) C Christoph Röllig (22Department of Internal Medicine I, University Hospital TU Dresden, Dresden, Germany) S Stefan Schwartz (23Department of Hematology, Oncology and Cancer Immunology (Campus Benjamin Franklin), Charité– Universitätsmedizin Berlin, corporate member of Freie Universität and Humboldt-Universität zu Berlin, Berlin, Germany) B Bernd Spriewald (25Department of Internal Medicine 5 - Hematology and Oncology, Friedrich-Alexander-Universität Erlangen-Nürnberg and Uniklinik Erlangen, Erlangen, Germany) B Björn Steffen (26Department of Medicine II, Hematology/Oncology, Goethe University Frankfurt, University Hospital, Frankfurt, Germany) K Klaus Wethmar (27Department of Medicine A, Hematology, Oncology, Hemostaseology and Pneumology, University Hospital Münster, Münster, Germany) H Hauke Busch N Nicola Gökbuget (26Department of Medicine II, Hematology/Oncology, Goethe University Frankfurt, University Hospital, Frankfurt, Germany) C Claudia D. Baldus L Lorenz Bastian M Monika Brüggemann (1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany)

Abstract

Abstract Lenalidomide, a maintenance treatment in multiple myeloma first-line therapy, increases the risk of secondary malignancies, including B-cell precursor acute lymphoblastic leukemia (B-ALL). We present a comprehensive molecular characterization of 57 patients with lenalidomide-associated B-ALL (LenB-ALL), revealing 3 mutational subgroups: (1) TP53mt (30%); (2) IDH2mt (p.R140Q) (23%); and (3) other, including NRAS/KRASmt. Remarkably, IDH2 R140Q mutations were highly enriched in LenB-ALL compared with those in primary B-ALL (P&amp;lt; .001). Furthermore, IKZF1 intragenic deletions, often subclonal and likely RAG recombinase-mediated, were observed in 54% (7/13) of IDH2mt patients with LenB-ALL. IDH2 mutations were not restricted to the leukemic clone: they persisted during measurable residual disease–negative remission and were identified in lymphoid as well as myeloid cell populations using fluorescence-activated cell sorting and single-cell RNA sequencing. This indicates a preleukemic origin of the IDH2 mutation within the context of clonal hematopoiesis. Transcriptomic and DNA methylation analyses revealed a distinct gene expression profile and a DNA hypermethylation phenotype in IDH2mt LenB-ALL, including IDH2mt-specific as well as lenalidomide-associated features. We propose that lenalidomide promotes the expansion of IDH2-mutated clonal hematopoiesis and, via IKAROS downregulation, induces a maturation arrest at the B-cell precursor stage. Subsequent genetic or epigenetic alterations render leukemogenesis independent of ongoing lenalidomide exposure. All these data define IDH2mt B-ALL as a distinct molecular subtype that is markedly overrepresented after lenalidomide treatment and highlight clonal hematopoiesis as a key contributing factor in the development of LenB-ALL.

Article Details

Journal Blood
Volume / Issue Vol. 148, Issue 7
Published August 13, 2026
Pages 856-866
ISSN 0006-4971
Publisher Elsevier BV

Journal Info

Blood

Elsevier BV

ISSN: 0006-4971 Health Sciences

Authors (38)

J

Johanna M. Horns

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

T

Thomas Beder

A

Axel Künstner

M

Malwine J. Barz

S

Sonja Bendig

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

C

Cecilia Bozzetti

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

G

Guranda Chitadze

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

N

Nikos Darzentas

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

K

Katharina Iben

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

M

Michaela Kotrova

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

J

José I. Martin-Subero

M

Mayukh Mondal

M

Martin Neumann

R

Raúl F. Pérez

A

Aeint-Steffen Ströh

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany

W

Wiebke Wessels

L

Lennart Lenk

10Department of Pediatrics I, University Hospital Schleswig-Holstein, Kiel, Germany

L

Lars Velten

B

Boris Böll

13Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany

K

Krischan Braitsch

14Department of Medicine III, TUM University Hospital, Technical University of Munich, Munich, Germany

V

Veit Bücklein

Ludwig Maximilian University Hospital, Munich, Germany

J

Johannes Duell

16Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, Germany

C

Christoph Faul

17Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology and Rheumatology, University Hospital Tübingen, Tübingen, Germany

W

Walter Fiedler

M

Maher Hanoun

19Department of Hematology and Stem Cell Transplantation, University Hospital Essen, Essen, Germany

S

Snjezana Janjetovic

20Department of Hematology and Cell Therapy, Helios Klinikum Berlin-Buch, Berlin, Germany

F

Felix Klingler

18Department of Oncology, Hematology and Bone Marrow Transplantation with Section Pneumology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

S

Stefan Knop

16Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, Germany

C

Christoph Röllig

22Department of Internal Medicine I, University Hospital TU Dresden, Dresden, Germany

S

Stefan Schwartz

23Department of Hematology, Oncology and Cancer Immunology (Campus Benjamin Franklin), Charité– Universitätsmedizin Berlin, corporate member of Freie Universität and Humboldt-Universität zu Berlin, Berlin, Germany

B

Bernd Spriewald

25Department of Internal Medicine 5 - Hematology and Oncology, Friedrich-Alexander-Universität Erlangen-Nürnberg and Uniklinik Erlangen, Erlangen, Germany

B

Björn Steffen

26Department of Medicine II, Hematology/Oncology, Goethe University Frankfurt, University Hospital, Frankfurt, Germany

K

Klaus Wethmar

27Department of Medicine A, Hematology, Oncology, Hemostaseology and Pneumology, University Hospital Münster, Münster, Germany

H

Hauke Busch

N

Nicola Gökbuget

26Department of Medicine II, Hematology/Oncology, Goethe University Frankfurt, University Hospital, Frankfurt, Germany

C

Claudia D. Baldus

L

Lorenz Bastian

M

Monika Brüggemann

1Department of Internal Medicine II (Hematology/Oncology), University Hospital Schleswig-Holstein Campus Kiel, Kiel, Germany