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A variant RhAG protein encoded by the RHAG*572A allele causes serological weak D expression while maintaining normal RhCE phenotypes

期刊: TRANSFUSION, 2019; 59 (1)

BACKGROUND: The molecular events resulting in a weak D phenotype include missense mutations, in- frame insertion, or deletion mutations of the RHD gene and hybrid RHD- CE- D hybrid alleles. Mutations in genes encoding the proteins that are required for proper membrane expression of Rh proteins, such as RhAG and ankyrin 1, can lead to absent or weakened expression of Rh antigens. STUDY DESIGN AND METHODS: Blood sample from a Chinese blood donor with a serological weak D phenotype was collected. RhAG antigen expression, RhD, and RhCE phenotypes were determined. Analysis of the RHD and RHCE genotypes by RH multiplex ligation- dependent probe amplification (MLPA), Sanger sequencing of the RHD exons, and next- generation sequencing (NGS) of the RHAG and ANK1 exons were performed. Expression studies in vitro were conducted by lentivirally transducing the mutant RHAG* 572A or wild- type RHAG, in combination with either RHD or RHCE constructs, into HEK 293 T cells. The expression of RhAG, RhD, and RhCE antigens was analyzed by flow cytometry. RESULTS: Serological weak D and normal C + c- E- e + phenotypes, normal CCDDee genotype determined by RH-MLPA, and normal sequence of the RHD gene by Sanger sequencing were demonstrated. A homozygous variant (c. 572G > A, p. Arg191Gln) of the RHAG gene was revealed by NGS analysis. Normal RhAG, weak RhD, and normal RhCE antigens were detected in cells transduced with the mutant RHAG* 572A, the mutant RHAG* 572A and RHD, and the mutant RHAG* 572A and RHCE constructs, respectively. CONCLUSION: The homozygous presence of RHAG* 572A allele results in weak D expression. It does not affect RhCE expression.

IF:3.11

Hemolytic disease of the fetus and newborn due to alloanti-M: three Chinese case reports and a review of the literature

期刊: TRANSFUSION, 2019; 59 (1)

BACKGROUND: Alloanti-M was once regarded as not clinically significant, with a few exceptions in extremely rare cases. However, an increasing number of cases of severe hemolytic disease of the fetus and newborn (HDFN), resulting in fetal hydrops and recurrent abortion caused by alloanti-M, have been reported mainly in the Asian population. STUDY DESIGN AND METHODS: Three pregnant Chinese women with a history of abnormal pregnancy with hydrops fetalis were encountered. During this pregnancy, a series of clinical examinations and an alloantibody identification against RBCs and platelets were conducted. Intrauterine transfusion and postnatal transfusion were then performed in the fetuses. In addition, the HDFN cases caused by alloanti-M reported in different ethnic groups as well as their clinical and serologic features are also summarized. RESULTS: Three pregnant women were identified with an M-N+ phenotype and IgM mixed with IgG alloanti-M in serum. Their fetuses were found by ultrasound examination and cord blood testing to have severe anemia. Additionally, an M+N+ phenotype and IgG alloanti-M were detected in the cord blood of the three fetuses with titers ranging from 1:1 to 1:128. Moreover, low reticulocyte counts and negative direct antiglobulin tests were also shown in two of the fetuses. After receiving intrauterine transfusions and postnatal transfusions several times, these three fetuses eventually survived and then healthfully developed in the follow-up tracking. CONCLUSION: Alloanti-M immunization can cause severe HDFN with hyporegenerative anemia, often seen in the Asian population, and suppression of erythropoiesis might account for it.

IF:3.11

Hemin impairs resolution of inflammation via microRNA-144-3p-dependent downregulation of ALX/FPR2

期刊: TRANSFUSION, 2019; 59 (1)

BACKGROUND: The pathomechanisms of complications due to blood transfusion are not fully understood. Elevated levels of heme derived from stored RBCs are thought to be associated with transfusion reactions, especially inflammatory responses. Recently, the proinflammatory effect of heme has been widely studied. However, it is still unknown whether heme can influence the resolution of inflammation, a key step of inflammatory response. STUDY DESIGN AND METHODS: A murine model of self-limited peritonitis was used, and resolution was assessed by resolution indices. Western blot, quantitative reverse transcriptase polymerase chain reaction, chemotaxis assay, luciferase reporter assay, and lentivirus infections were used to investigate possible mediating mechanisms in neutrophils. RESULTS: The administration of hemin by intraperitoneal injection significantly increased the leukocyte infiltration and prolonged the resolution interval by approximately 7 hours in mouse peritonitis. In vitro, hemin significantly downregulated ALX/FPR2 protein levels (p < 0.05), a key resolution receptor, leading to the suppression of proresolution responses triggered by the proresolution ligand resolvin D1. Subsequently, miR-144-3p, selected by prediction databases, was found to be significantly upregulated by hemin (p < 0.05). The inhibition of miR-144-3p attenuated the inhibitory effect of hemin on lipoxin A(4) receptor (ALX)/formyl peptide receptor 2 (FPR2) protein expression (p < 0.05). Luciferase reporter assay confirmed that miR-144-3p directly bound ALX/FPR2 3'-UTR. MiR-144-3p overexpression significantly downregulated ALX/FPR2 protein levels, whereas miR-144-3p inhibition led to a significant increase in ALX/FPR2 (p < 0.05). CONCLUSION: Our results suggest that hemin prolongs resolution in self-limited inflammation, and this action is associated with downregulation of ALX/FPR2 mediated by hemin-induced miR-144-3p. These findings demonstrate a novel mechanism of hemin derived from stored RBCs for inflammatory response.

IF:3.11

HIV prevalence and incidence estimates among blood donors in five regions in China

期刊: TRANSFUSION, 2020; 60 (1)

BACKGROUND Previous data, although scant, indicated that the incidence of HIV in China has increased over the past decade. There is a growing concern about the impact of the HIV epidemic on blood safety. METHODS AND MATERIALS We used donation data from five geographically-disperse blood centers in 2013-2016 participating in the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) China program to estimate HIV prevalence and incidence among blood donors. Multivariable logistic regression model was used to examine factors associated with HIV infection in Chinese blood donors. RESULTS The overall HIV prevalence among first-time donors from 2013 through 2016 was 68.04 per 100,000 donors (95% CI 61.68-74.40). The HIV incidence rate was estimated to be 37.93 per 100,000 person-years (95% CI 30.62-46.97) among first-time donors and 20.55 per 100,000 person-years (95% CI 16.95-24.91) among repeat donors. There was substantial variation in HIV prevalence and incidence rates across blood centers. Multivariable logistic regression results showed that among first-time donors, being male, older than 25 years, minority ethnicity, less than college education, and certain occupations (commercial services, factory workers, retired, unemployed, or self-employed) were associated with positive HIV confirmatory testing results. CONCLUSION HIV prevalence and incidence among blood donors remain low in the selected five regions in China; however, an increasing trend is observed at some blood centers. It is important to monitor HIV epidemiology in Chinese blood donors on a continuous basis, especially among populations and regions of higher risk.

Preventing murine transfusion-related acute lung injury by expansion of CD4(+)CD25(+)FoxP3(+) Tregs using IL-2/anti-IL-2 complexes

期刊: TRANSFUSION, 2019; 59 (2)

BACKGROUND: Transfusion-related acute lung injury (TRALI) is one of the most serious adverse events following transfusion, and there is no specific treatment in clinical practice. However, regulatory T cells (Tregs) have been suggested to play a potential role in the treatment of TRALI. This study investigated whether interleukin (IL)-2 or IL-2/anti-IL-2 complexes (IL-2c), which are mediators of Treg expansion, can modulate the severity of antibody-mediated TRALI in vivo. STUDY DESIGN AND METHODS: This study utilized a mouse model of the "two-hit" mechanism: BALB/c mice were primed with lipopolysaccharide (LPS) as the first hit, and then TRALI was induced by injecting major histocompatibility complex Class I antibodies. Mice injected with LPS only or LPS combined with isotype control antibodies served as controls. For the Tregdepleted groups, mice were infused with anti-mouse IL-2Ra first and then subjected to the same treatments as the TRALI group. Regarding IL-2-and IL-2c-treated mice, recombinant murine IL-2 or IL-2c was intraperitoneally administered to mice for 5 consecutive days before induction of the TRALI model. Samples were collected 2 hours after TRALI induction. RESULTS: Prophylactic administration of IL-2 or IL-2c to mice prevented the onset of edema, pulmonary protein levels, and proinflammatory factors that inhibited polymorphonuclear neutrophil aggregation in the lungs. Furthermore, the percentage of CD4+ CD25+ FoxP3+ Tregs was expanded in vivo using IL-2 and IL-2c compared to TRALI mice, as was confirmed through analysis of the spleen, blood, and lung. CONCLUSION: This study validates that the protective mechanisms against TRALI involve CD4+ CD25+ FoxP3+ Tregs, which can be expanded in vivo by IL-2 and IL-2c. This results in increased IL-10 levels and decreased IL-17A, thereby prophylactically preventing antibodymediated murine TRALI.

IF:3.11

M1-polarized alveolar macrophages are crucial in a mouse model of transfusion-related acute lung injury

期刊: TRANSFUSION, 0; ()

BACKGROUND The pathogenesis of transfusion-related acute lung injury (TRALI) progress is incompletely understood, and specific therapies for TRALI are lacking. Alveolar macrophages (AMs) are critical for initiation and resolution of lung inflammation. However, the role of AMs in the pathogenesis of TRALI-associated lung failure is poorly understood. STUDY DESIGN AND METHODS Mouse model for in vivo imaging of interleukin (IL)-6 activation in AMs was established by intratracheal instillation of a lentiviral vector carrying the luciferase reporter gene. The TRALI mouse model was produced by intraperitoneal lipopolysaccharide plus intravenous major histocompatibility complex Class I monoclonal antibody treatment. We focused on the changes in AMs in the lung during TRALI and examined whether targeting AMs is an effective strategy to alleviate this condition. MEASUREMENTS AND MAIN RESULTS We confirmed that TRALI progress is accompanied by IL-6 activation in AMs. Further study showed that AMs undergo M1 activation during TRALI progress. AM depletion protected mice from TRALI, and transfusion of M1-polarized AMs into 34-1-2 s-treated mice elevated acute lung injury, indicating that the severity of TRALI was able to be ameliorated by targeting AM polarization. Next, we showed that alpha(1)-antitrypsin (AAT) expression improved lung injury by modulating the production of IL-6 in AMs and decreased polarization of AMs toward the M1 phenotype. CONCLUSIONS M1-polarized AMs are crucial in a mouse model of TRALI, and AAT may serve as a future treatment for TRALI by regulating the polarization of AMs.

Stored red blood cells enhance in vivo migration of dendritic cells by promoting reactive oxygen species-induced cytoskeletal rearrangement

期刊: TRANSFUSION, 2019; 59 (4)

BACKGROUNDA complex array of physicochemical changes occurs in red blood cells (RBCs) during storage, leading to enhanced posttransfusion clearance. Dendritic cells (DCs) play crucial roles in the engulfment of aged RBCs; however, it is unclear how stored RBCs (sRBCs) modulate their responses to inflammatory stimuli and DC migration ability. STUDY DESIGN AND METHODSIn this study, we examined whether sRBCs affect the migration ability of DCs and elucidated the detailed mechanisms mediating this process. Murine RBCs were incubated with marrow DCs after removing the storage supernatant. The effects of sRBCs on cytokine secretion from DCs, surface marker expression, and homing ability were examined. RESULTSMore sRBCs were internalized by DCs than fresh RBCs (fRBCs), and RBC accumulation significantly promoted the expression of allostimulatory molecules and the secretion of Th1-type cytokines in the presence of lipopolysaccharide (LPS). In particular, the lymphoid-tissue homing ability of transfused DCs treated with sRBCs (sRBC-DCs) was also significantly greater than that of fRBCs. Up regulation of CCR7 and improved organization of the cytoskeleton were observed in sRBC-DCs, and blocking Rho/Rho-associated protein kinase (ROCK), PI3K/Akt, and NF-B pathways greatly hindered cytoskeletal rearrangement. Moreover, high levels of reactive oxygen species (ROS) were detected in sRBC-DCs, and treatment with N-acetylcysteine simultaneously decreased the lymph node-homing ability of DCs and phosphorylation of RhoA, ROCK1, and cortactin. CONCLUSIONSsRBCs initiated differential immune responses compared to fRBCs, and the presence of LPS augmented this phenomenon. Up regulation of CCR7 and ROS production promotes cytoskeletal reorganization and contributes to the increased homing of sRBCs-DCs.

IF:3.11

Reversal of the antiplatelet effect of ticagrelor by simulated platelet transfusion

期刊: TRANSFUSION, 2019; 59 (5)

BACKGROUND Reversal of antiplatelet therapy is desirable in patients presenting with life-threatening bleeding or requiring urgent surgery. This study aimed to examine ticagrelor reversal using donor platelets and to explore the effects of residual ticagrelor on donor platelets. STUDY DESIGN AND METHODS In Cohort 1, 16 healthy subjects were treated with ticagrelor 90 mg twice daily alone or in combination with aspirin 100 mg once daily for 7 days followed by single blood sampling for preparation of platelet-rich plasma. An additional 16 healthy subjects served as controls. In Cohort 2, 16 healthy subjects were treated with ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily for 7 days followed by serial blood samplings for preparation of platelet-poor plasma (PPP). An additional 16 healthy subjects served as controls. RESULTS In Cohort 1, inhibition of adenosine diphosphate-induced platelet aggregation (PLADP) by ticagrelor could not be fully reversed by mixing with up to 90% control platelets, whereas inhibition of arachidonic acid-induced platelet aggregation by aspirin was fully reversed with the addition of 60% control platelets. In Cohort 2, 10% PPP obtained from ticagrelor-treated subjects reduced PLADP from 74% to 40% at 2 hours, 72% to 58% at 6 hours, and 73% to 59% at 10 hours, while 10% or 20% PPP obtained from clopidogrel-treated subjects did not inhibit PLADP. CONCLUSION The antiplatelet effect of ticagrelor cannot be fully reversed by donor platelets, which could be explained by the presence of active drug. The effect of residual drug on donor platelets appears to be evident for at least 10 hours after ticagrelor ingestion.

IF:3.11

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