German Red Cross

About: German Red Cross is a healthcare organization based out in Berlin, Germany. It is known for research contribution in the topics: Transplantation & Mesenchymal stem cell. The organization has 653 authors who have published 1146 publications receiving 40111 citations. The organization is also known as: Deutsches Rotes Kreuz & DRK.

Natural killer cells generated from human induced pluripotent stem cells mature to CD56brightCD16+NKp80+/- in-vitro and express KIR2DL2/DL3 and KIR3DL1

Abstract: The differentiation of human induced pluripotent stem cells (hiPSCs) into T and natural killer (NK) lymphocytes opens novel possibilities for developmental studies of immune cells and in-vitro generation of cell therapy products. In particular, iPSC-derived NK cells gained interest in adoptive anti-cancer immunotherapies, since they enable generation of homogenous populations of NK cells with and without genetic engineering that can be grown at clinical scale. However, the phenotype of in-vitro generated NK cells is not well characterized. NK cells derive in the bone marrow and mature in secondary lymphoid tissues through distinct stages from CD56brightCD16- to CD56dimCD16+ NK cells that represents the most abandoned population in peripheral blood. In this study, we efficiently generated CD56+CD16+CD3- NK lymphocytes from hiPSC and characterized NK-cell development by surface expression of NK-lineage markers. Hematopoietic priming of hiPSC resulted in 31.9% to 57.4% CD34+CD45+ hematopoietic progenitor cells (HPC) that did not require enrichment for NK lymphocyte propagation. HPC were further differentiated into NK cells on OP9-DL1 feeder cells resulting in high purity of CD56brightCD16- and CD56brightCD16+ NK cells. The output of generated NK cells increased up to 40% when OP9-DL1 feeder cells were inactivated with mitomycine C. CD7 expression could be detected from the first week of differentiation indicating priming towards the lymphoid lineage. CD56brightCD16-/+ NK cells expressed high levels of DNAM-1, CD69, natural killer cell receptors NKG2A and NKG2D, and natural cytotoxicity receptors NKp46, NKp44, NKp30. Expression of NKp80 on 40% of NK cells, and a perforin+ and granzyme B+ phenotype confirmed differentiation up to stage 4b. Killer cell immunoglobulin-like receptor KIR2DL2/DL3 and KIR3DL1 were found on up to 3 and 10% of mature NK cells, respectively. NK cells were functional in terms of cytotoxicity, degranulation and antibody-dependent cell-mediated cytotoxicity.

YKL-39 as a Potential New Target for Anti-Angiogenic Therapy in Cancer.

Abstract: YKL-39 belongs to the evolutionarily conserved family of Glyco_18-containing proteins composed of chitinases and chitinase-like proteins. Chitinase-like proteins (CLPs) are secreted lectins that lack hydrolytic activity due to the amino acid substitutions in their catalytic domain and combine the functions of cytokines and growth factors. One of the major cellular sources that produce CLPs in various pathologies, including cancer, are macrophages. Monocytes recruited to the tumor site and programmed by tumor cells differentiate into tumor-associated macrophages (TAMs), which are the primary source of pro-angiogenic factors. Tumor angiogenesis is a crucial process for supplying rapidly growing tumors with essential nutrients and oxygen. We recently determined that YKL-39 is produced by tumor-associated macrophages in breast cancer. YKL-39 acts as a strong chemotactic factor for monocytes and stimulates angiogenesis. Chemotherapy is a common strategy to reduce tumor size and aggressiveness before surgical intervention, but chemoresistance, resulting in the relapse of tumors, is a common clinical problem that is critical for survival in cancer patients. Accumulating evidence indicates that TAMs are essential regulators of chemoresistance. We have recently found that elevated levels of YKL-39 expression are indicative of the efficiency of the metastatic process in patients who undergo neoadjuvant chemotherapy. We suggest YKL-39 as a new target for anti-angiogenic therapy that can be combined with neoadjuvant chemotherapy to reduce chemoresistance and inhibit metastasis in breast cancer patients.

Allogeneic transplant procurement in the times of COVID-19: Quality report from the central European cryopreservation site.

Abstract: Because of limitations of transportation imposed by the COVID-19 pandemic, current recommendation calls for cryopreservation of allogeneic stem cell transplants before patient conditioning. A single cell therapy laboratory was selected to function as the central cryopreservation hub for all European registry donor transplants intended for the Australian-Pacific region. We examined properties of these transplants to ascertain how quality is maintained. We analyzed 100 pandemic-related allogeneic mobilized blood-derived stem cell apheresis products generated at 30 collection sites throughout Europe, shipped to and cryopreserved at our center between April and November of 2020. Products were shipped in the cool, subsequently frozen with DMSO as cryoprotectant. Irrespective of origin, all products were frozen within the prescribed shelf-life of 72 h. Prior to cryopreservation, viable stem cell and leukocyte count according to the collection site and our reference laboratory were highly concordant (r2 = 0.96 and 0.93, respectively) and viability was > 90% in all instances. Median nominal post-thaw recovery of viable CD34+ cells was 42%. Weakly associated with poorer CD34+ cell recovery was higher leukocyte concentration, but not time lag between apheresis or addition of cryopreservant, respectively, and start of freezing. The correlation between pre- and post-thaw CD34+ cell dose was high (r2 = 0.85), hence predictable. Neutrophil and platelet engraftment were prompt with no evidence of dose dependency within the range of administered cell doses (1.31–15.56 × 106 CD34+ cells/kg). General cryopreservation of allogeneic stem cell transplants is feasible. While more than half of the CD34+ cell content is lost, the remaining stem cells ensure timely engraftment.

Non-specific and specific anti-HCV results correlated to age, sex, transaminase, rhesus blood group and follow-up in blood donors

Abstract: Second generation enzyme immunoassays (EIA-2) for antibodies to hepatitis C virus (anti-HCV) have a higher specificity and sensitivity than first generation enzyme immunoassays (EIA-1). We studied how many anti-HCV-positive blood donors were missed by the EIA-1, how many were false positive, how false-positive donors should be dealt with and how the results of the EIA-2 correlate to demographic data and serum alanine aminotransferase (ALT) level. A total of 208, 544 northern German blood donors, not preselected for anti-HCV negativity, were tested for anti-HCV with EIA-2 and, if repeatably reactive (rr), were retested with a licensed supplementary test (RIBA-2). 0.43% of the donors were EIA-2 rr, but only 0.12% of women and 0.09% of men were RIBA-2 positive. RIBA-2 positivity rates were very low in donors 18 to 27 years old (0.03% and 0.05%) and rose with age in women but not in men. Infected women were significantly more often Rhesus-negative than men. The rate of unspecifically positive EIA-2 results (entirely negative in RIBA-2) increased with age in both sexes and did not correlate with ALT. The ALT distribution was age-dependent with a different pattern for men and women. Confirmation of EIA-2 results with RIBA was rare when ALT was low and frequent when ALT was high. ALT screening before introduction of Anti-HCV detected one out of six infected donors. To exclude this one infectious donation, 46 uninfected donations had to be excluded in addition. Only 8% of the then RIBA-2-positive donors were not detected by EIA-1. Apparent seroconversions in EIA-2 are usually not specific: only 1 out of 66 apparent seroconversions could be confirmed by RIBA-2 suggesting recent HCV infection. 0.15% of the donor population showed an inconsistent EIA-2 pattern during follow-up. We conclude that donors should not be excluded from further donations, even on the basis of multiple EIA-1 positive results or on the basis of only one EIA-2 positive donation. Anti-D-immunoglobulin prophylaxis may have been a source of infection in some Rhesus-negative women. ALT screening should not be discontinued because recent HCV infection can be detected earlier by ALT than by anti-HCV, but exclusion limits should be elevated to increase specificity and limit unnecessary exclusion of donations.

Next-Generation Sequencing Technologies in Blood Group Typing.

Abstract: Sequencing of the human genome has led to the definition of the genes for most of the relevant blood group systems, and the polymorphisms responsible for most of the clinically relevant blood group antigens are characterized. Molecular blood group typing is used in situations where erythrocytes are not available or where serological testing was inconclusive or not possible due to the lack of antisera. Also, molecular testing may be more cost-effective in certain situations. Molecular typing approaches are mostly based on either PCR with specific primers, DNA hybridization, or DNA sequencing. Particularly the transition of sequencing techniques from Sanger-based sequencing to next-generation sequencing (NGS) technologies has led to exciting new possibilities in blood group genotyping. We describe briefly the currently available NGS platforms and their specifications, depict the genetic background of blood group polymorphisms, and discuss applications for NGS approaches in immunohematology. As an example, we delineate a protocol for large-scale donor blood group screening established and in use at our institution. Furthermore, we discuss technical challenges and limitations as well as the prospect for future developments, including long-read sequencing technologies.