Direct antiglobulin test (DAT), also known as Coomb's test, is a method used in blood immunology to detect whether the surface of red blood cells is sensitized by immunoglobulin or complement. It is mainly used in the diagnosis of autoimmune hemolytic anemia (AIHA), neonatal hemolytic anemia, hemolytic transfusion reaction and blood matching during blood transfusion. DAT positive has always been the focus of researchers, because it has an important impact on the efficacy of blood transfusion. In recent years, there has been extensive research on the identification of DAT positivity types and the distribution characteristics of diseases in clinical patients, and the study on hemolytic disease of the newborn has also been popular. However, the transfusion safety of DAT-positive blood donors has been a hot topic in the field of blood transfusion for many years. Moreover, there is no clear requirement from the state on the handling of DAT-positive blood and whether DAT-positive blood donors should be deferred from donation. Therefore, this article reviews the serological studies on DAT immunotyping and IgG subtype typing of voluntary blood donors, as well as the impact of DAT-positive blood on blood transfusion safety, in order to provide references for the blood issuance strategy of DAT-positive blood and whether DAT-positive blood donors should be deferred.

Cluster of differentiation 36 (CD36) is a highly glycosylated double transmembrane glycoprotein, which is involved in the inflammatory response and immune regulation of the body. It plays a key role in mediating the mechanism of immune-related blood transfusion reactions and regulating the function of immune cells. It has an important impact on blood transfusion safety and has become a current research hotspot. This article reviews and comprehensively analyzes the research progress of the specific role of CD36 in the immune response of blood transfusion and its regulatory mechanism at home and abroad. Combined with clinical cases and experimental data, the pathophysiological mechanism of CD36 in immune response and its immune-mediated blood transfusion safety issues are reviewed. It is expected to provide new theoretical support and practical guidance for the field of blood transfusion safety and promote the further development of blood transfusion medicine.

Debates persist regarding the efficacy and safety of azvudine, particularly its real-world outcomes. This study involved patients aged ≥60 years who were admitted to 25 hospitals in mainland China with confirmed SARS-CoV-2 infection between December 1, 2022, and February 28, 2023. Efficacy outcomes were all-cause mortality during hospitalization, the proportion of patients discharged with recovery, time to nucleic acid-negative conversion (T _NANC), time to symptom improvement (T _SI), and time of hospital stay (T _HS). Safety was also assessed. Among the 5884 participants identified, 1999 received azvudine, and 1999 matched controls were included after exclusion and propensity score matching. Azvudine recipients exhibited lower all-cause mortality compared with controls in the overall population (13.3% vs. 17.1%, RR, 0.78; 95% CI, 0.67-0.90; P = 0.001) and in the severe subgroup (25.7% vs. 33.7%; RR, 0.76; 95% CI, 0.66-0.88; P < 0.001). A higher proportion of patients discharged with recovery, and a shorter T _NANC were associated with azvudine recipients, especially in the severe subgroup. The incidence of adverse events in azvudine recipients was comparable to that in the control group (2.3% vs. 1.7%, P = 0.170). In conclusion, azvudine showed efficacy and safety in older patients hospitalized with COVID-19 during the SARS-CoV-2 omicron wave in China.

Objective:To investigate the serological and molecular genetic characteristics of a voluntary blood donor with combined FUT1 and ABO blood group gene variants causing para-Bombay and A2 subtype, and to review relevant literature on para-Bombay blood types carrying alleles such as FUT101W.37 and FUT101W.23. Methods:A blood donor with para-Bombay and A 2 subtype who participated in voluntary blood donation at the Dongguan Blood Center in August 2023 was selected as the study subject. Serological tests were performed to identify the ABO blood group, Lewis blood group antigens, and unexpected serum antibodies in the donor. Adsorption-elution test was conducted to detect trace antibodies in the blood donor′s plasma to trace the A, B and H antigens on the red blood cell surface. Sanger sequencing was carried out to analyze the sequences of the FUT1 and ABO genes. Using keywords such as " para-Bombay" " FUT1*01W.37" and " FUT1*01W.23" both in Chinese and English, relevant literature on para-Bombay blood type subjects carrying FUT1*01W.37 and FUT1*01W.23 alleles was retrieved from the CNKI, Wanfang Data Knowledge Service Platform, and PubMed databases, and the retrieval time was set as from the establishment of database to December 2022. This study has been approved by the Ethics Committee of Dongguan Blood Center (No. 2022005), and informed consent of blood donation was obtained from the blood donor. Results:Serological testing of the blood donor revealed inconsistent results between forward and reverse ABO blood typing, negative H antigen on the red blood cell surface, Le(a-b+ ) secretor type for Lewis blood group, and unexpected anti-H antibodies in the plasma, indicating a suspected para-Bombay type. Absorption-elution test suggested the blood type of the blood donor to be para-Bombay and A subtype. Sanger sequencing showed that the donor has harbored homozygous FUT1*(c.35T+ c.803A)/(c.35T+ c.803A) variant, with the FUT1*(c.35T+ c.803A) allele containing a dual nucleotide variant unrecorded by the International Society of Blood Transfusion (ISBT) FUT1 gene variant database, which was similar to the weakly functional allele of FUT101W. 37(c.803G>A) as recorded by the ISBT database. The ABO genotype was heterozygous ABOA2.05/O.01.02. Combining the results of serological and genetic testing, the blood type of the blood donor was determined to be para-Bombay and A 2 subtypes. Literature review has identified a pregnant women from Qingdao carrying the FUT1*01W.37 allele and 2 individuals carrying a heterozygous FUT1*01W.23 allele. Conclusion:This study has discovered a blood donor with coexisting para-Bombay and ABO subtype blood groups. Based on the characteristics of red blood cell surface antigens, the FUT1*01W.37 as classified as an FUT1 null allele.

The proband was a 33-year-old pregnant woman (G4P1) who suffered spontaneous abortion in the first 3 months of pregnancy without a history of blood transfusion or transplantation. The fourth pregnancy was clinically diagnosed with threatened abortion, and a cesarean section was performed on June 28, 2023, at the Obstetrics and Gynecology Department of Dongguan Hospital of Traditional Chinese Medicine. During cross-matching tests, unexpected antibodies were detected in the proband′s plasma, which could not be specifically identified, and no suitable donor red blood cells could be found. The blood samples were sent to the Blood Transfusion Laboratory of Dongguan Blood Center. The laboratory used serology to identify the erythrocyte phenotype of the proband and confirmed the proband as having a rare p blood group. The unexpected antibody was identified as anti-PP1P K, and gene sequencing of the proband revealed that the new allele A4GALT* (c.100G>A+c.418_428delins) was homozygous, which is speculated to cause changes in the polypeptide chains p.Veral34ile and p.GERln140TRPFS *73, and inactivation of α1, 4-galactosyltransferase. At the same time, another new allele A4GALT*c.100G>A was found in family members, and it was predicted that the single change of p.Val34Ile caused by this mutation would not affect protein function or enzyme activity.

OBJECTIVE: To explore the genetic mechanism underlying a case with para-Bombay phenotype. METHODS: The ABO and Lewis phenotype were identified with serological methods. The coding regions of exons 6 and 7 of the ABO and FUT1 genes were amplified with PCR and directly sequenced. Haploid sequence analysis was carried out on the variant sites of the FUT1 gene. RESULTS: Serological analysis confirmed that the proband has a rare para-Bombay phenotype. Direct sequencing revealed that he was a B.01/O.01.02 heterozygote for the ABO gene, and had heterozygous deletion for the 768 and 881-882 sites of the FUT1 gene. Further haploid analysis showed that the c.881_882delTT deletion has occurred in one haploid while c.768delC was present in the other haploid. The proband was therefore determined as a FUT1*01N.13/01N.20 heterozygote, which have resulted in frameshift in polypeptide chain p.Phe294Cysfs*40 and p.Val257Phefs*23, respectively. CONCLUSION A rare bi-allelic heterozygous deletion of para-Bombay phenotype has been identified in a blood donor. The c.881_882delTT and c.768delC deletions may decrease the activity of α-1,2-fucosyltransferase.
Animals ; Male ; ABO Blood-Group System/genetics* ; Alleles ; Fucosyltransferases/genetics* ; Genotype ; Heterozygote ; Mutation ; Phenotype ; Humans

Streptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.
Animals ; Biofilms ; Dental Caries ; Dental Plaque ; Rats ; Streptococcus mutans/genetics*

Objective : To study the changes of acid resistance, oxidation resistance and high osmotic pressure resistance of Streptococcus mutans after knockout of rnc gene and its possible regulatory mechanism. Methods: Through PCR ligation mutagenesis, an rnc knockout mutant (Smurnc) was constructed. Acid tolerance, oxidation tolerance and high osmotic pressure tolerance were compared between Smurnc and the wild strain respectively. Real-time RT-PCR was used to verify the changes in expression of stress tolerance related genes at the transcriptional level. Results : When rnc gene was knocked out, the acid tolerance (χ2=13.464, P=0.001) and oxidation tolerance (χ2=4.505, P=0.048) of Streptococcus mutans was significantly decreased, but the high osmotic pressure tolerance was significantly increased (χ2=11.971, P=0.001). Expression of stress tolerance related genes luxS and ropA (0.64 and 0.51 times expression of the wild strain) had been significantly downregulated (P<0.001). Expression of htrA and brpA (1.56 and 1.80 times expression of the wild strain) had been significantly upregulated (P<0.001). Conclusion The deletion of rnc gene affects the expression of the environmental tolerance related genes of Streptococcus mutans, which reduces its acid resistance and oxidation resistance, and enhances its tolerance to hypertonic pressure.

nal surface coil,and it can be a promising method to diagnose interphalangeal joints lesions.

Objective To investigate the application of 3D ultrashort TE double echo pulse sequence in the bone and joint MR imaging. Methods Eight volunteers and a porcine fibula in vitro with intact muscle were involved in this study. Among the volunteers, one was suspected with meniscus tear, the others were asypmtomatic. MR imaging of 3D ultrashort TE double echo pulse sequence were performed on the tibial diaphysis, knee joint, ankle and wrist of each volunteer and the porcine fibula in vitro. Using the first echo images subtract with the second echo images, we observed the subtracted images from the primary double echo images and MPR images respectively. We then compared the difference of SNR. Four different echo times of the first echo (TE1) in the images were set as 0. 08 ms, 0. 16 ms, 0. 24 ms, 0. 35 ms. The quality of the subtracted images from the primary double echo images of the four different TE1 was compared.The MIP images from the primary double echo images with TE1 of 0. 08ms were performed to display the 3D structure of the ankle tendons. The data were analysed with One-Way ANOVA and Paired-Samples t test statistically. Results The 3D images of the tendons were displayed through MIP of the subtracted images from the primary double echo images. The cortical bones, periosteums, tendons and menisci of the 8 volunteers appeared as high signal intensity in UTE pulse sequence. The SNR of the subtracted images from MPR images (SNR, 3.76 ± 0. 88) was significantly higher than those from the primary double echo images(SNR,2. 82±0. 75) (t = - 4. 851, P < 0. 01). There were significant differences among the subtracted images from each of the four different TE1. The highest quality were obtained from the TE1 of 0.08ms. The CNR were as follows: CNR<,0.08ms>1.74±0. 54, CNR<,0.16ms> 1.35 + 0. 60, CNR0.24ms>1.20±0. 48,CNR<0.35ms> 0.89±0. 24 (F = 3. 681, P < 0. 05). The artifacts appeared markedly with prolonging of the TE1.Conclusion The MRI of ultrashort TE double pulse sequence may display the short T2 components that appeared as low signal with conventional clinical MR imaging, which made it pessible to quantify the tissues containing a majority of short T2 components.