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Chimeric antigen receptor (CAR)-T cells are increasingly used for the treatment of hematologic malignancies. Treatment success relies highly upon sufficient expansion of CAR-T effector cells. Accordingly, longitudinal quantification of CAR-T cells during therapy is clinically important. Techniques to quantify CAR-T cells in patient blood samples are based on flow cytometry and PCR. However, cellular kinetics of CAR-T cells are very complex and under current investigation. In this study, feasibility of CAR-T cell quantification by cell-free DNA (cfDNA) was analyzed. cfDNA isolated from 74 blood samples of 12 patients during lymphoma treatment with the anti-CD19 CAR-T cell product axicabtagene ciloleucel (axi-cel) were analyzed. Concentrations of cfDNA specific for the CAR-T gene construct (cfCAR-DNA) and a reference gene were quantified by a newly designed digital-droplet PCR (ddPCR) assay. Detection and quantification of cfCAR-DNA was feasible and reliable for all patients included. Relative quantification of cfCAR-DNA compared to a reference gene, suitable for genomic DNA analysis, was heterogeneous in treatment responders and non-responders. In contrast, parallel analyses of cfCAR-DNA and reference cfDNA in a patient-specific approach gave insight into active lymphoma killing and treatment responses. In summary, plasma cfDNA determination in lymphoma patients is a promising tool for future clinical decision making., Graphical abstract, The study proves the feasibility to quantify cell-free CAR-DNA in lymphoma patients during CAR-T cell treatment by a novel digital-droplet PCR assay. Combined analysis of cell-free CAR-DNA and reference cell-free DNA displays CAR-T cell-mediated lymphoma killing in individual patients.

While acute myeloid leukemia (AML) is the most common type of acute leukemia in adulthood, the constellation of AML associated with central diabetes insipidus (CDI) is rare and typically occurs in patients with chromosome 3 or 7 abnormalities. This subgroup of AML is associated with a poor clinical outcome. In this report, we present a young woman with AML and concurrent CDI in the presence of inversion(3)(q21q26). The AML was refractory to the induction therapy “7 + 3”. Afterwards, the patient underwent allogenic stem cell transplantation (alloHSCT) and is still remaining in complete remission (CR) from AML as well as CDI 440 days after alloHSCT. Subsequently, in the largest study concerning patients with AML and CDI reported so far, we discuss additional cases from the literature. We demonstrated that patients with AML and CDI belong to the adverse prognostic group and clearly benefit from alloHSCT.

Introduction Acute myeloid leukemia (AML) is, if untreated, a fatal hematologic neoplasia. Failure of the first induction chemotherapy is a hallmark for a poor prognosis. Early recognition of therapy failure is crucial for planning further therapies. Therefore, international guidelines recommend a bone marrow biopsy around day 14 after the beginning of induction therapy. Hypocellular bone marrow on day 14 is still gold standard for therapy assessment and further therapy strategy. Despite this, non-invasive ways for the evaluation of induction therapy were looked for in the past years. Methods We collected peripheral blood cell counts and routine laboratory values of patients treated with “7 + 3” induction therapy. Ratios of absolute cell counts of monocytes and neutrophils (MNR) were calculated daily, and the values were compared in patients with failure of the first induction therapy and patients with therapy response. Results 54 patients were included, 12 of which had failure of first induction therapy. The MNR following therapy was highly correlated with the bone marrow results. With the right cut-off, the MNR provides a valid and reliable tool for identification of patients with failure of first induction therapy with a sensitivity of 83.3% and a specificity of 87.8% on day 18. Conclusions We propose a novel and non-invasive method for detection of failure of first induction therapy in patients with de novo AML and “7 + 3” induction therapy. The MNR is free of cost since the required cell counts are performed routinely for each patient undergoing intensive chemotherapy.

Introduction Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a curative approach for multiple hematologic diseases. The success of alloHSCT is evaluated by analyzing the proportion of living donor cells in blood and bone marrow samples of the recipient (chimerism analysis). To monitor the engrafted cells, donor's individual genetic markers are analyzed in peripheral blood and bone marrow samples, usually by using short tandem repeat (STR) analysis. An alternative method to measure chimerism is based on insertion and deletion markers (InDels) analyzed by digital droplet PCR (ddPCR); however, this approach is rarely evaluated in clinical practice. Methods In this study, we examined the usefulness of ddPCR-based chimerism analysis against the standard STR analysis in samples around day+30 after alloHSCT in clinical practice using peripheral blood and bone marrow samples. Results The median absolute difference between ddPCR and STR analysis was 0.55% points for bone marrow chimerisms and 0.25% points for peripheral blood chimerisms, respectively, including variation in the range of maximum 2% for both methods. The results of every single sample gave the same clinical message. Conclusion According to our data, chimerism analysis by ddPCR has an excellent correlation with STR-based analyses. Due to its fast and easy applicability, the ddPCR technique is suitable for chimerism monitoring in clinical practice.