Clinical significance of the detection of Rh blood group antigens and irregular antibodies in pregnant women with a second pregnancy

Objective:To investigate the phenotype distribution of five antigens of Rh blood group system and the specificity of Rh blood group irregular antibodies in pregnant women with second child.To analyze the relationship between Rh blood group antibody and hemolytic disease of the newborn(HDN)in second-child pregnant women,and to provide laboratory basis for the diagnosis and treatment of hemolytic disease of the newborn(Rh-HDN).Methods:500 pregnant women with second child were collected as the study group and 500 pregnant women with first pregnancy as the control group(all pregnant women underwent obstetric examination in the integrated obsteric clinic of our hospital from January 2020 to January 2021).To detectethe Rh blood group antigens(D,C,c,E,e)of the two groups of samples,screene the irregular antibodies,identify the specificity of irregular antibodies,determine the titer and record the hemolytic disease of the newborn of pregnant women with positive Rh blood group antibodies.Results:There were 11 Rh phenotypes in the pregnant women with second child in the study group:CCDee(152cases,30.4%),CcDEe(136cases,27.2%)CcDee(84cases,16.8%),ccDEE(30cases,6%),ccDee(31cases,6.2%),CCDEe(14cases,2.8%),ccDEe(9cases,1.8%),cc dee(18cases,3.6%),CCDEE(2cases,0.4%),CcdEe(12cases,2.4%),Ccdee(6cases,1.2%),CCd ee(6cases,1.2%).A total of 42 cases(8.4%)in the pregnant women with second child were negative for RhD.There were 10 Rh phenotypes in the pregnant women with first pregnancy in the control group:CCDee(144cases,28.8%),CcDEe(138cases,27.6%),CcDee(90cases,18%),ccDEE(42cases,8.4%),ccDee(28cases,5.6%),CCDEe(10cases,2%),ccDEe(8cases,1.6%),cc dee(19cases,3.8%),CCDEE(1cases,0.2%),CcdEe(11cases,2.2%),Ccdee(9cases,1.8%).A total of 39 cases(7.8%)in the pregnant women with first pregnancy were negative for RhD.In the pregnant women with second child in the study group,the positive rate of irregular antibody screening was 4.0%(20/500),and the specificity of Rh blood group antibodies was found as follows:anti-E 1.8%(9/500),anti-D 1.4%(7/500),anti-C 0.4%(2/500)and anti-Ec 0.4%(2/500).The positive rate of irregular antibody screening in the pregnant women with first pregnancy in the control group was 0,and the difference between the two groups was statistically significant(P<0.05).Rh-HDN was found in 10 newborns(2%)of the 20 women with positive irregular antibodies in the pregnant women with second child,and the antibody titer during pregnancy was more than 32.No Rh-HDN occurred in newborns in the pregnant women with first pregnancy,and the difference between the two groups was statistically significant(P<0.05).Conclusion:Pregnancy stimulation can increase the probability of irregular antibodies in pregnant women,and irregular antibodies in Rh blood group can easily cause Rh-HDN,so attention should be paid to routine detection of five antigens of Rh blood group and irregular antibody screening during prenatal examination.It is helpful for the early detection of Rh-blood irregular antibodies and the assessment of fetal or neonatal risk of Rh-HDN.

Blood group type antigens in pancreatic intraductal papillary mucinous neoplasms

BACKGROUND: There are few data on blood group(BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms(IPMNs). METHODS: BG type and tumor BG-antigen(glycoprotein) expression(studied by immunohistochemistry on tissue microarrays) were analyzed with regard to characteristics of 101 surgically resected pancreatic IPMNs. RESULTS: Non-O BG type predicted invasive carcinoma independently from high serum CA19-9 and male gender. BG type A was observed more frequently in women than in men. Chronic pancreatitis was more frequently seen in patients with BG type B or AB. Aberrant tumor expression(with regard to BG type) of loss of A antigen expression type occurred in 15.0% of IPMNs and of loss of B antigen expression type in 62.5% of IPMNs. Intraneoplasm BG-antigen expression was not related to dysplasia grade or invasion. CONCLUSION: The results of the study suggest that in pancreatic IPMN, non-O BG type predicted invasive carcinoma, whereas for intratumor BG-antigen expression no specific patterns were detected with regard to the progression of glandular epithelial dysplasia or invasion.

Identification and Characterization of Peptide Mimics of Blood Group A Antigen

In order to investigate peptide mimics of carbohydrate blood group A antigen, a phage display 12-mer peptide library was screened with a monoclonal antibody against blood group A antigen, NaM87-1F6. The antibody-binding properties of the selected phage peptides were evaluated by phage ELISA and phage capture assay. The peptides were co-expressed as glutathione S-transferase （GST） fusion proteins. RBC agglutination inhibition assay was performed to assess the natural blood group A antigen-mimicking ability of the fusion proteins. The results showed that seven phage clones selected bound to NaM87-1F6 specifically, among which, 6 clones bore the same peptide sequence, EYWYCGMNRTGC and another harbored a different one QIWYERTLPFTF. The two peptides were successfully expressed at the N terminal of GST protein. Both of the fusion proteins inhibited the RBC agglutination mediated by anti-A serum in a concentration-dependent manner. These results suggested that the fusion proteins based on the selected peptides could mimic the blood group A antigen and might be used as anti-A antibody-adsorbing materials when immunoabsorption was applied in ABO incompatible transplantation.

Overloading of differentiated Caco-2 cells during lipid transcytosis induces glycosylation mistakes in the Golgi complex

Overloading the intestine enterocytes with lipids induced alteration of the Golgi complex(GC;Sesorova et al.,2020)and could cause glycosylation errors.Here,using differentiated Caco-2 cells with the established 0[I]blood group phenotype(no expression of the blood antigens A and B[AgA,AgB]under normal conditions)as a model of human enterocytes we examined whether the overloading of these cells with lipids could cause errors in the Golgi-dependent glycosylation.We demonstrated that under these conditions,there were alterations of the GC and the appearance of lipid droplets in the cytoplasm.Rare cells produced AgA and AgB.This suggested that after overloading of enterocytes with lipids,AgA were mistakenly synthesized in individual enterocytes by the Golgi glycosyltransferases.These mistakes could explain why in the absence of AgA and AgB antibodies against them exist in the blood.

Polymer-mediated immunocamouflage of red blood cells: Effects of polymer size on antigenic and immunogenic recognition of allogeneic donor blood cells

Developing a practical means of reducing alloimmunization in chronically transfused patients would be of significant clinical benefit. Immunocamouflaging red blood ceils （RBCs） by membrane grafting of methoxypoly（ethylene glycol） （mPEG） may reduce the risk of allo-immunization. The results of this study showed that antibody recognition of non-ABO antigens was sig- nificantly reduced in an mPEG-dose- and polymer size-dependent manner, with higher molecular weight mPEGs providing better immunoprotection. Furthermore, in vivo immunogenicity was significantly reduced in mice serially transfused with mPEG-modified xenogeneic （sheep; sRBCs）, allogeneic （C57B1/6）, or syngeneic （Balb/c） RBCs. Following a primary transfu- sion of sRBCs, mice receiving mPEG-sRBCs showed a 〉90% reduction in anti-sRBC IgG antibody levels. After two transfusions, mice receiving mPEG-sRBCs showed reductions of 〉80% in anti-sRBC IgG levels. Importantly, mPEG-modified autologous cells did not induce neoantigens or an immune （IgG or IgM） response. These data suggest that the global immuno- camouflage of RBCs by polymer grafting may provide a safe and cost-effective means of reducing therisk of alloimmunization.