HPA Frequencies in the Syrian Population.

BACKGROUND: Exposure to allogenic Human Platelet Antigens (HPAs) can lead to antibody formation causing different immunological reactions. Frequencies of common HPA antigens differ between ethnic groups and should be known to calculate potential alloimmunization risk. Syrian refugees are the largest group of applicants for asylum in Germany in 2017. However, no study on HPA antigen frequencies in the Syrian population exists. METHODS: DNA from blood samples of 96 volunteers with Syrian origin was isolated. The genotype of HPA-1, -2, -3, -4, -5, -6, -9, and -15 was determined using a commercialized polymerase chain reaction kit with sequence-specific primers (SSP-PCR). Data were compared with data formerly obtained from the German population and diverse other studies. RESULTS: In Syrian population, the gene frequencies of HPA-1a/1b, -2a/2b, -3a/3b, -4a/4b, -5a/5b, -6a/6b, -9a/9b, and -15a/15b were 0.837/0.163, 0.875/0.125, 0.630/0.370, 1.000/0.000, 0.837/0.130, 1.000/0.000, 1.000/0.000, and 0.457/0.543, respectively. CONCLUSIONS: There are no significant differences between HPA antigen frequencies in the Syrian and German population. Therefore, we do not see a need for special precaution in the selection of blood products or in pregnancy of interethnic couples with regard to HPA.

Human Neutrophil Alloantigen Genotype Frequencies Among Syrian Population.

BACKGROUND: Human neutrophil antigens (HNA) are able to provoke allo- and autoimmune antibodies which lead to reactions like autoimmune and neonatal neutropenia. However, until now no data about HNA genotype distribution in Syrian population exists. The aim of this study was to determine the HNA allele frequencies in the largest group asking for asylum in Germany since 2015. Allele frequencies were compared to data from German blood donors. Therefore, we calculated the risk of alloimmunization and associated transfusion reactions, as well as the risk of developing neonatal neutropenia for newborns of mixed race couples. METHODS: We isolated DNA from blood samples of 100 Syrian volunteers and typed them for HNA-1, -3, -4, and -5 by using a commercial polymerase chain reaction kit with sequence-specific primers (SSP-PCR). Then, we compared the HNA genotype distribution with data from Germans and different populations from literature. RESULTS: In Syrian population the gene frequencies for HNA-1a, HNA-1b, and HNA-1c were 0.375, 0.580, and 0.040, for HNA-3a and -3b 0.742 and 0.258, for HNA-4a and -4b 0.860 and 0.140, and for HNA-5a and -5bw 0.660 and 0.340, respectively. No statistically significant differences between Syrian and German gene frequencies were found. CONCLUSIONS: This study is the first to report HNA gene frequencies in Syrian population. There is no significant difference of HNA genotype frequencies compared to the German population. Therefore, no elevated alloimmunization risks in transfusion of blood and blood components and in pregnancy of mixed race couples exist.

Transfusion-related alloimmune neutropenia with no pulmonary complications: one donor-five cases.

BACKGROUND: Neutrophil alloantibodies are well-known triggers of transfusion-related acute lung injury (TRALI) and also cause immune neutropenia. Alloimmune neutropenia due to transfusion is an isolated phenomenon that is only rarely identified. Its incidence is specified in the literature as being less than one in 10,000 transfused plasma-containing units. We expect that this phenomenon is underreported. STUDY DESIGN AND METHODS: We observed five cases of alloimmune neutropenia with no respiratory complications with only one case initially reported as a suspected transfusion reaction. The other four cases were detected in the course of the subsequent lookback investigation. RESULTS: The first case was reported as a potential transfusion reaction when a female patient showed a decrease in the white blood cell count after a platelet (PLT) transfusion. Examinations of the donor blood revealed an antibody against the human neutrophil antigen HNA-1b; the recipient was typed HNA-1b positive and HNA-1a negative. After examining the blood counts of other patients who previously received PLT concentrates from the same donor, we identified four other patients with an unreported decrease in the leukocyte and/or granulocyte count of more than approximately 50% after transfusion. CONCLUSION: HNA antibodies are generally regarded as potential triggers of TRALI. Here we describe an HNA antibody that reproducibly caused transfusion-related neutropenia only without pulmonary complications. Factors predisposing patients to TRALI development are widely discussed. Our case suggests that antibody characteristics are also relevant in the development of TRALI. Current measures to prevent TRALI should also prevent transfusion-related alloimmune neutropenia.

Influence of Irradiation on Leukodepleted Small Unit Red Blood Cell (RBC) Bags for Infant Transfusion in Additive Solution SAG-M.

BACKGROUND: To reduce transfusion-associated graft-versus-host disease irradiation of blood products is widely accepted. There is little data about the effect of gamma-irradiation on leukoreduced RBCs stored in SAG-M that are subdivided for use in transfusion to preterm infants and small children. METHODS: We studied 30 leukoreduced SAG-M preserved RBC bags. All RBCs were leukoreduced on the collection day. The 30 units were divided into two groups. Every unit was divided into three bags. One of these bags served as nonirradiated control (group 1A, group 2A), the other two were gamma-irradiated at different times. In vitro evaluation of irradiated and nonirradiated units was performed on the days +3, +7, +14, +21, and +28 from the day of collection. RESULTS: Gamma irradiation induced a higher increase of extracellular hemoglobin, LDH, and potassium than non-irradiated storage over the time. No irradiated or non-irradiated unit showed a hemolysis rate over the recommended limit of 0.8% over the 28 day period. CONCLUSIONS: Our findings show that subdivision of RBCs does not have an appreciable influence on the storage of leukoreduced, irradiated RBCs in AS SAG-M. Our "worst case scenario" was irradiation on day +3 after donation and subsequent storage until day +28. Especially for infant use, it is important to have the possibility to irradiate even late after donation, because this procedure offers the possibility to use one RBC bag over a longer period of time and to reduce the donor exposure for infants. Therefore, subdivided leukoreduced RBCs can be safely irradiated until day +14 and subsequently stored until day +28 after donation.

Comparison of Simultaneous CD34+ and CD3+ Quantification with a Modified Stem Cell Enumeration Kit on Two Different Flow Cytometers.

BACKGROUND: Quantification of CD34+ cells in peripheral blood stem cell apheresis is normally performed by single platform flow cytometric measurements according to the ISHAGE protocol. Peripheral blood stem cell concentrates (PBSC) produced by apheresis normally contain many T cells. Those T cells can be used for production of donor lymphocyte infusion doses, if abundant amounts of CD34+ cells have been collected. Therefore, it is of interest to know both the CD3+ and the CD34+ cell count of allogeneic PBSC. This is the first study comparing the performance of a modified ISHAGE protocol allowing additional quantification of CD3+ cells on two different flow cytometers, the FACSCalibur and the FACSVerse, respectively. METHODS: CD45+ and CD34+ cell concentrations were measured using a standard and a modified ISHAGE protocol including CD3+ cell quantification on both machines. All cell concentrations were measured using a Trucount bead based stem cell enumeration kit. The FACSVerse machine can additionally be equipped with a sample volume sensor allowing cell quantification without using beads. The samples analysed were taken from granulocyte-colony-stimulating factor mobilized peripheral blood stem cell apheresis procedures (pre- and post-apheresis, and apheresis concentrate). RESULTS: There were no significant differences in cell concentrations measured by the standard and modified ISHAGE protocol, regardless of which machine had been used when using bead quantification. No significant differences between the results of the two flow cytometers using the modified ISHAGE protocol were observed. Pearson´s correlation was always > 0.96, and regression coefficients were higher than 0.93. The only significant differences were observed between bead quantification and volume sensor quantification on the FACSVerse machine. CONCLUSIONS: The modified ISHAGE protocol can effectively be used on both flow cytometers tested, especially if bead quantification is used.

Quality of Clotting Factor Activity in Fresh Frozen Plasma at Thaw with a Microwave System and after Storage at 4 degrees C for 48 Hours.

BACKGROUND: Uncontrolled hemorrhage in polytrauma patients usually results in rapid need of blood products. Despite the shorter thawing times of microwave devices for heating fresh frozen plasma (FFP), their use has remained controversial, and just a few laboratory analyses have been published on this topic. The aim of this study was to analyse the quality of clotting factors immediately after thawing FFP with a microwave device and after 48-hour post thaw storage at 4 degrees C. METHODS: 24 FFP units of all four ABO blood groups (six of each blood group) were thawed with a Transfusio-therm 2000 and later stored at 4 degrees C for 48 hours. Samples were drawn aseptically and investigated on various clotting factors and protein proteases (fibrinogen, antithrombin, FII, FV, FVII, FVIII, FIX, FX, FXI, FXIII, vWF antigen and activity, protein S, and protein C) using standard coagulation and chromogenic assays immediately after thawing and again after a 48-hour storage period at 4 degrees C. All units were tested for both anaerobic and aerobic microbial contamination using standard operating procedures immediately after thawing. RESULTS: After thawing, all coagulation factors and protein protease activities were within normal ranges. Blood group O individuals had approximately 25% lower plasma levels of vWF antigen and activity. After a 48-hour storage period at 4 degrees C, FVIII and FIX activities declined significantly in all blood groups, whereas the remaining clotting factors remained comparably stable. CONCLUSIONS: Immediately after rapid thawing using a microwave system, all FFP units contained adequate coagulation factor activities to maintain hemostatic activity at the time of product thaw. The post thaw refrigerated storage caused an anticipated decrease in factor VIII and IX activities, but retained normal coagulation factor levels of many plasma proteins. Therefore we conclude that the Transfusio-therm 2000 has no clinically significant influence on the activity of clotting factors and plasma proteases in FFP units.

The effect of cell concentrations from different cell populations on the viability of umbilical blood stem cells.

BACKGROUND: In addition to bone marrow or peripheral blood derived stem cells, cord blood (CB) is an alternative source for hematopoietic stem cells. This report shows the impact of higher concentrations of leukocytes, mononu- clear cells (MNCs), and CD34-positive cells on the viability of CB derived stem cells after cryopreservation. METHODS: Statistical analysis of data from 5520 CB units, prepared and cryopreserved from 2003 through 2011, was performed with appropriate software. Cell concentrations for leukocytes, platelets, red blood cells (RBCs), CD34-positive leukocytes, viable leukocytes, and MNCs were determined. The proliferation and differentiation capacity was assessed in cell culture assays. RESULTS: Content of leukocytes, CD34-positive leukocytes, and MNCs decreased after thawing. The recovery rate of colony forming units (CFUs) (29.05%) correlated significantly with leukocytes, platelets, RBCs, MNCs, CD34- positive leukocytes, and viable leukocytes. The recovery rate for erythroblasts (3.33%) correlated significantly with leukocytes, CD34-positive leukocytes, MNCs, and viable leukocytes. In the different cell concentration groups only RBCs showed a negative influence on viability. The concentrations of leukocytes, platelets, and CD34-positive leukocytes before cryopreservation correlated positively with the concentrations of leukocytes, CD34-positive leukocytes, MNCs as well as with the cell viability after thawing. CONCLUSIONS: Increased cell concentrations in CB do not limit the recovery of CD34-positive leukocytes nor the viability of leukocytes or the number of CFUs after thawing. On the contrary, CB units with high cell concentrations show a better outcome than units with low cell concentrations. Only RBCs seem to have a negative influence on CB quality.