Markus Wiesneth

Growth differentiation factor 15 in patients with congenital dyserythropoietic anaemia (CDA) type II

Congenital dyserythropoietic anaemias (CDAs) are heterogeneous, hereditary disorders hallmarked by ineffective erythropoiesis and tissue iron overload. Growth differentiation factor 15 (GDF15) was suggested to mediate iron overload in iron-loading anaemias, such as the thalassaemias and CDAI by suppressing hepcidin, the key regulator of iron absorption. Here, we show that serum GDF15 concentrations are elevated in subjects with CDAI and CDAII. Despite similar disease characteristics, CDAI patients present with significantly higher GDF15 concentrations compared to CDAII patients. Hepcidin concentrations are inappropriately low in CDAII patients considering the severe hepatic iron overload associated with this disorder. GDF15 significantly correlates with the degree of anaemia (Hb), the response of erythropoiesis (reticulocyte index) as well as with iron availability in the serum (transferrin saturation). The observation that GDF15 is elevated in CDAII patients is consistent with the proposal that GDF15 is among the erythroid factors down-regulating hepcidin and contributing to iron overload in conditions of dyserythropoiesis.

Expression of human leucocyte antigens and co-stimulatory molecules on blasts of patients with acute myeloid leukaemia.

Summary. Recently, leukaemia‐associated antigens (LAA) recognized by T lymphocytes, such as Wilms tumour‐1 (WT‐1) or pathogenesis‐related protein‐1 (PR‐1), have been identified. For immunotherapies that employ antigen peptides, either alone or pulsed on dendritic cells (DC), the expression of human leucocyte antigen (HLA) molecules on the targeted leukaemic blasts (LB) is crucial. The co‐stimulatory molecules CD80 and CD86 give the secondary signal to T lymphocytes that is necessary for the lysis of leukaemia cells, and CD40 enhances the efficacy of antigen presentation. Here, the expression of HLA‐ABC, HLA‐A2, HLA‐DR, CD40, CD80 and CD86 was flow cytometrically examined in blood samples from 24 healthy volunteers (HV), 24 patients with newly diagnosed acute myeloid leukaemia (AML) and five patients with relapsed AML. The expression of HLA‐ABC, CD40, CD80 and CD86 was significantly reduced on LB in comparison with monocytes of HV. HLA‐A2 and HLA‐DR expression was similar on LB and on monocytes of HV. In AML patients, the expression of HLA and CD86 molecules was significantly higher on LB than on CD33/CD34‐negative monocytes. CD40 and CD80 molecules were deficient on AML blasts. The preservation of HLA molecules and CD86 on LB of the majority of AML patients at the time of diagnosis and even at relapse of the disease are prerequisites for LAA‐targeted immunotherapies in these patients.

S100A4 and Uric Acid Promote Mesenchymal Stromal Cell Induction of IL-10+/IDO+ Lymphocytes

Simple stress or necrotic cell death with subsequent release of damage-associated molecular patterns (DAMPs) is a characteristic feature of most advanced tumors. DAMPs within the tumor microenvironment stimulate tumor-associated cells, including dendritic cells and mesenchymal stromal cells (MSCs). The presence of tumor-infiltrating MSCs is associated with tumor progression and metastasis. Oxidized necrotic material loses its stimulatory capacity for MSCs. As a DAMP, S100A4 is sensitive to oxidation whereas uric acid (UA) acts primarily as an antioxidant. We tested these two biologic moieties separately and in combination for their activity on MSCs. Similar to necrotic tumor material, S100A4 and UA both dose-dependently induced chemotaxis of MSCs with synergistic effects when combined. Substituting for UA, alternative antioxidants (vitamin C, DTT, and N-acetylcysteine) also enhanced the chemotactic activity of S100A4 in a synergistic manner. This emphasizes the reducing potential of UA being, at least in part, responsible for the observed synergy. With regard to MSC proliferation, both S100A4 and UA inhibited MSCs without altering survival or inducing differentiation toward adipo-, osteo-, or chondrocytes. In the presence of S100A4 or UA, MSCs gained an immunosuppressive capability and stably induced IL-10– and IDO-expressing lymphocytes that maintained their phenotype following proliferation. We have thus demonstrated that both S100A4 and UA act as DAMPs and, as such, may play a critical role in promoting some aspects of MSC-associated immunoregulation. Our findings have implications for therapeutic approaches targeting the tumor microenvironment and addressing the immunosuppressive nature of unscheduled cell death within the tumor microenvironment.

Safety and frequency of whole blood donations from elderly donors

Backgroundu2002 Within the coming decades, a steadily growing demand for blood products will face a shrinking blood donor population in many countries. After increasing the donor age of repeat donors for whole blood donation (WB) from 68 to 70u2003years in 2009 in our Blood Service, we investigated whether this is sufficient as a safe and effective strategy to sustain future blood supply.

Donor deferral rates after the implementation of a new German blood donor questionnaire

Background: The implementation of a new national German blood donor questionnaire was proposed to improve donor and recipient safety. Methods: We compared deferral/exclusion rates of whole blood donors before (May 2010, n = 64,735) and after (May 2011, n = 71,687) the implementation of a new blood donor questionnaire. Considering seasonal variations, analysis was performed with respect to collection site (mobile vs. fixed), sex, donor status (first-time vs. repeat), age, and the frequencies of sexual risk behavior and other reasons for deferral. Results: We observed a statistically significant increase (p < 0.001) of the overall deferral/exclusion rate from 6.2 to 8.1%, irrespective of type of collection site (fixed: from 6.0 to 8.5%; mobile: from 6.2 to 8.0%), sex (females: from 7.5 to 9.9%; males: from 5.1 to 6.6%), donor status (first-time donors: from 19.7 to 24.7%; repeat donors: from 4.6 to 6.3%) or age (18–29 years: from 9.1 to 11.7%; 60–71 years: from 5.1 to 6.6%). Confidential self-exclusion increased from 0.08 to 0.14% (p < 0.001). Besides risk behavior, various medical reasons could be identified that explain this increase. Conclusions: The new blood donor questionnaire resulted in an increased deferral/exclusion of all donor groups. Thus the impact on future blood supply must be considered carefully, and long-term studies and investigation of donor acceptance will be needed.

Healthy donor hematopoietic stem cell mobilization with biosimilar granulocyte-colony-stimulating factor: safety, efficacy, and graft performance

Biosimilar granulocyte‐colony‐stimulating factors (G‐CSFs) have been available in the European Union since 2008, and Sandoz biosimilar filgrastim was approved in the United States in March 2015 for all of the reference products indications except acute radiation syndrome. Biosimilar G‐CSFs have been largely embraced by the medical community, except for some reservations about healthy‐donor stem cell mobilization, for which use outside of clinical studies was cautioned against by some members of the scientific community.

Acute myeloid leukemia with mutated nucleophosmin 1: an immunogenic acute myeloid leukemia subtype and potential candidate for immune checkpoint inhibition

Clinical and preclinical data suggest that acute myeloid leukemia (AML) with mutated nucleophosmin 1 ( NPM1 mut) might constitute an immunogenic leukemia subtype. In general, AML with NPM1 mut correlates with better prognosis, but the underlying mechanisms still remain to be elucidated. Our group

Donor lymphocyte infusion leads to diversity of specific T cell responses and reduces regulatory T cell frequency in clinical responders: DLI augments specific T cell responses and reduces Treg

T cell responses against malignant cells play a major role in maintaining remission and prolonging overall survival in patients after allogeneic stem cell transplantation and donor lymphocyte infusion (DLI) due to graft‐versus‐leukemia effect. For better characterization of the T cell responses, we assessed frequency and diversity of leukemia‐associated antigen (LAA)‐specific cytotoxic T cells using ELISpot and pMHC multimer assays and analyzed the frequency of regulatory T cells (Treg) as well as cytokine profiles before/after DLI. The data were correlated to the clinical course of patients. Significantly more LAA‐derived T cell epitopes (p = 0.02) were recognized in clinical responders (R) when compared to nonresponders (NR). In addition, pMHC multimer‐based flow cytometry showed a significantly higher frequency of LAA‐specific T cells in R versus NR. The frequency of Treg in R decreased significantly (p = 0.008) while keeping stable in NR. No differences in T cell subset analysis before/after DLI were revealed. Clinical responders were correlated to specific immune responses and all clinical responders showed an increase of specific immune responses after DLI. Cytokine assays using enzyme‐linked immunosorbent assay showed a significant increase of IL‐4 after DLI. Taken together, an increase of specific CTL responses against several LAA after DLI was detected. Moreover, this study suggests that enhanced LAA diversity in T cell responses as well as decreasing numbers of Treg contribute to clinical outcome of patients treated with DLI.

Gesetzliche Vorgaben, Verordnungen und Richtlinien für die Gewinnung und Herstellung von peripheren Blutstammzellen

in ausreichender Menge nur nach entsprechender Vorbehandlung gewonnen werden. Die Vorbehandlung der spendenden Person zur Mobilisation von allogenen peripheren Blutstammzellen hat gemas § 9 Abs. 1 Transfusionsgesetz (TFG) [2] nach dem Stand der medizinischen Wissenschaft zu erfolgen, wobei im Falle der allogenen Spende § 8 Abs. 2–4 TFG entsprechend gelten. § 8 Abs. 2 TFG fordert fur die Vorbehandlung, dass 1. die Risiken der Vorbehandlung arztlich vertretbar sind, 2. die schriftliche Einwilligung nach entsprechender Aufklarung erteilt wurde, 3. die Durchfuhrung von einer sachkundigen arztlichen Person geleitet wird, 4. ein dem Stand der medizinischen Wissenschaft entsprechender Behandlungsplan erstellt wurde, 5. die arztliche Uberwachung wahrend der Vorbehandlung gewahrleistet ist, 6. der zustandigen Behorde die Vorbehandlung angezeigt worden ist und 7. das zustimmende Votum der zustandigen Ethik-Kommission vorliegt. lnwieweit der Gesetzgeber nach den inzwischen sehr umfangreichen Erfahrungen mit den bei gesunden Spendern zur Stammzellmobilisation zugelassenen Arzneimitteln weiterhin ein Ethikvotum fur die Vorbehandlung fordert bzw. kunftig separate, von der Spenderimmunisierung nach S 8 TFG unabhangige Vorgaben macht, bleibt abzuwarten. Bei der Aufklarung und Einwilligung ist das Gesetz zur Verbesserung der Rechte von Patientinnen und Patienten (Patientenrechtegesetz) [3] zu beachten. Das schriftliche Einverstandnis zur Vorbehandlung und Gewinnung von allogenen Blutstammzellen setzt die Einwilligungsfahigkeit der spendenden Person voraus. Bei Minderjahrigen kann ab Einleitung