Veit Bücklein

Background: Blinatumomab (Blina), a CD19×CD3 bispecific T cell engager, is approved for the treatment of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), yet resistance remains a major challenge and the mechanisms driving treatment failure remain poorly understood. Methods: To define the immunological determinants of resistance, we performed longitudinal profiling of peripheral blood T cells and the immune milieu of 34 patients receiving Blina using flow cytometry (n=19), single-cell CITE-seq (n=13), ex vivo Blina-induced cytotoxicity (n=26) and serum proteomics (n=17). Results: At baseline, Responders (R) were enriched for CD8 ₊ effector memory T cells (T _EM ) expressing higher levels of cytotoxic genes and their transcriptional regulator ZNF683 . Conversely, CD8 ⁺ T _EM from Non-Responders (NR) displayed transcriptional features of activation without proportionate cytotoxic commitment. Over the course of the first treatment cycle, NR exhibited a progressive expansion of TIM3 ₊ CD8 ₊ T cells that correlated with a rapid loss of ex vivo cytotoxic function. Linking baseline state to post-treatment T-cell exhaustion, the magnitude of TIM3 ₊ CD8 ₊ expansion correlated inversely with baseline ZNF683 expression in CD8 ₊ T _EM . Beyond T-cell-intrinsic features, NR harbored an immunosuppressive milieu characterized by higher circulating levels of M2-polarizing factors (CSF-1, HGF) and the TIM-3 ligand Galectin-9, which correlated positively with the magnitude of TIM3 ₊ CD8 ₊ T-cell expansion. Conclusions: These findings indicate that post-Blina CD8 ⁺ T-cell exhaustion is associated with resistance and it is shaped by both reduced ZNF683 -dependent cytotoxic programming in CD8 ₊ T _EM and an immunosuppressive milieu. This provides a rationale for risk stratification based on baseline transcriptional profiling of CD8 ₊ T _EM and for combinatorial strategies targeting the suppressive microenvironment.

Die Durchflusszytometrie stellt einen essenziellen Teil der hämatologischen Stufendiagnostik dar. Sie ist der Goldstandard für die Diagnosestellung einer Reihe von hämatologischen Neoplasien. Bei korrekter Durchführung der Methodik und Befundung ermöglicht die Durchflusszytometrie komplexe hämatologische Diagnosen innerhalb kürzester Zeit zu stellen – sofern die Indikationsstellung und Interpretation stimmt. Flow cytometry is an essential part of hematological stepwise diagnostics. It is the gold standard for diagnosing a range of hematological neoplasms. When performed and interpreted correctly, flow cytometry enables complex hematological diagnoses to be made within a very short time – provided that the indication and interpretation are correct. Article published online: 20 January 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

Mit Rituximab hat die Immuntherapie bereits vor Jahrzehnten Einzug in die Routinebehandlung von B-Zell-Lymphomen gehalten. Die Zulassung neuer bispezifischer T-Zell-rekrutierender Antikörper und der adoptiven Immuntherapie mit CAR-T-Zellen bringt tiefgreifende Änderungen der Therapiealgorithmen bei aggressiven und indolenten Lymphomen mit sich. Im Folgenden werden die wichtigsten aktuell zugelassenen T-Zell-rekrutierenden Behandlungsstrategien vorgestellt. The introduction of immunologically targeted therapies has represented a significant advancement in the treatment of B-cell lymphomas, particularly aggressive B-cell lymphoma. CD19 CAR-T cells such as Axicabtagen-Ciloleucel (Axi-cel) and Lisocabtagen Maraleucel (Liso-cel) have been approved since 2022 and 2023, respectively, for second-line therapy of Diffuse Large B-Cell Lymphomas (DLBCL), when there is primary refractory disease or relapse within 12 months after the end of first-line therapy. These therapies result in a significant improvement in progression-free survival compared to the previous standard therapy (salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation). Especially in elderly patients or patients with underlying medical conditions, CAR-T cell therapies like Axi-cel and Liso-cel demonstrate acceptable tolerability and high efficacy. Furthermore, bispecific T-cell-engaging antibodies (“bispecifics”) such as Glofitamab, Epcoritamab, and Mosunetuzumab also represent promising treatment options for patients with relapsed disease after failure of second- or later line therapy and show efficacy even in a subset of patients relapsing after CD19 CAR-T cells. However, randomized study results for these substances are not yet available. They are expected to be used in earlier lines of therapy in the future, especially in combination with standard chemotherapy regimens. Common side effects of bispecific antibody therapies are cytokine release syndrome (CRS) and immune-mediated cytopenias, whereas immune-cell associated neurotoxicity syndrome (ICANS) is relatively rare compared to CD19 CAR T cells. In summary, bispecifics represent a novel, highly effective immunotherapy for the treatment of lymphomas with a very favourable toxicity profile. Article published online: 15 May 2024 © 2024. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

ZUSAMMENFASSUNG: Immer mehr Patienten mit therapierefraktären B-Zell-Neoplasien in Deutschland werden mit CAR-T-Zellen behandelt. Die Zelltherapie ermöglicht bisher ungekannte Therapieerfolge, ist jedoch auch mit einer Reihe spezifischer Nebenwirkungen assoziiert. Zusätzlich stellt sie als personalisierte Tumortherapie besondere Anforderungen an die Patientenlogistik. Im folgenden Beitrag wird erläutert, worauf in der Versorgung von CAR-T-Zell-Patienten besonders zu achten ist.

Immunotherapy is currently investigated as treatment option in many types of cancer. So far, results from clinical trials have demonstrated that significant benefit from immunomodulatory therapies is restricted to patients with select histologies. To broaden the potential use of these therapies, a deeper understanding for mechanisms of immunosuppression in patients with cancer is needed. Soft-tissue sarcoma (STS) presents a medical challenge with significant mortality even after multimodal treatment. We investigated function and immunophenotype of peripheral natural killer (NK) cells from chemotherapy-naive STS patients (1st line) and STS patients with progression or relapse after previous chemotherapeutic treatment (2nd line). We found NK cells from peripheral blood of both STS patient cohorts to be dysfunctional, being unable to lyse K562 target cells while NK cells from renal cell cancer (RCC) patients did not display attenuated lytic activity. Ex vivo stimulation of NK cells from STS patients with interleukin-2 plus TKD restored cytotoxic function. Furthermore, altered NK cell subset composition with reduced proportions of CD56^dim cells could be demonstrated, increasing from 1st- to 2nd-line patients. 2nd-line patients additionally displayed significantly reduced expression of receptors (NKG2D), mediators (CD3ζ), and effectors (perforin) of NK cell activation. In these patients, we also detected fewer NK cells with CD57 expression, a marker for terminally differentiated cytotoxic NK cells. Our results elucidate mechanisms of NK cell dysfunction in STS patients with advanced disease. Markers like NKG2D, CD3ζ, and perforin are candidates to characterize NK cells with effective antitumor function for immunotherapeutic interventions.