Antibodies to histo-blood group substances A and B: agglutination titers, Ig class, and IgG subclasses in healthy persons of different age categories

Isotypes and IgG subclasses of ABO antibodies from sera of 235 healthy blood donors were determined by an enzyme-linked immunosorbent assay (ELISA). Synthetic A and B trisaccharide-bovine serum albumin glycoconjugates were used for coating and monoclonal antibodies for the detection of heavy chain isotypes. Hemagglutination titers were determined in addition. Blood donors were between 20 and 67 years old, and at least 10 sera per 10-year age category and ABO blood group were included in this study. Antibody concentrations were expressed as a percentage of an internal standard, and sera with subclass-restricted anti-A and/or anti-B (anti-A/B) responses were used to normalize the ELISA values of IgG subclasses. A good correlation between the sum of the four subclasses and the total anti-A/B IgG values (rs = 0.81 for anti-A and 0.84 for anti-B) was obtained. IgG1 and IgG2 were the most predominant subclasses, but were found in various proportions in different individuals. Donor-to-donor variation exceeded age-related changes for all measured parameters. The correlation of anti-A IgM, IgG, IgA, and their sum with the agglutination titers was significant and revealed rs values of 0.70, 0.65, 0.65, and 0.80, respectively. For anti-B as well, the correlation of ELISA values with the agglutination titer was best when all three isotypes were added. We conclude that anti-A/B IgA, together with IgM and IgG, substantially contributes to the agglutination reaction. Potentially autoreactive antibodies were detected in sera of blood groups A, B, and AB.     

正常O型人血清ABO血型抗体主要类别的分析

目的通过检测O型及A/B型人血清中IgM类及IgG类抗体的效价,分析正常O型人血清中ABO血型抗体的主要类别。方法分别以盐水介质法和间接抗人球蛋白法检测O型及A/B型人血清中IgM类和IgG类抗A或抗B抗体的效价。结果 O型人血清中IgM类抗A/抗B抗体效价均显著高于IgG类抗A/抗B抗体（均P〈0.01）;O型人血清中IgM类抗A/抗B抗体效价与B/A型人比较无显著性差异（均P〉0.05）,而IgG类抗A/抗B抗体效价显著高于B/A型人（均P〈0.01）;O型人血清中IgG类与IgM类抗A/抗B抗体效价的比值均显著高于B/A型人（均P〈0.01）。结论 O型人ABO血型抗体仍以IgM类为主,但其IgG类抗体效价及在血清中所占的比例要明显高于A/B型人。     

血小板悬浮血浆ABO血型抗体效价与保存时间消长性研究

目的研究单采血小板悬浮血浆中的抗-A和抗-B效价及其与保存时间的相关性。方法应用盐水凝集法检测血浆IgM抗-A、抗-B效价;应用2-巯基乙醇(2-Me)破坏IgM抗体后,抗人球蛋白法检测血浆IgG抗-A、抗-B效价。结果在保存期内A、B、O型单采血小板悬浮血浆中抗-A(IgM或/和IgG)或/和抗-B(IgM或/和IgG)效价间相互比较差异无统计学意义(P>0.05),其效价不随保存时间延长而降低(P>0.05);10%O型单采血小板悬浮血浆中抗-A和抗-B效价均较高。结论单采血小板输注时可不进行血液交叉配合试验,但须同型输注;尤其是O型悬浮血浆含较高的抗-A或/和抗-B(IgM或/和IgG)效价时,不能输注给其他血型患者。     

Effect of ABO mismatching on a radioimmunoassay for platelet compatibility. Successful adsorption of ABO alloantibodies with synthetic A and B substance

IgG and IgM anti-A and/or -B agglutinin titers were determined on 17 serum samples (5 group 0, 7 group A, 5 group B) to range from 8 to 1024. The presence of hemolysins was also evaluated. Single adsorptions with solid-state synthetic A and B substances greatly reduced or eliminated anti-A and -B titers but did not adsorb known platelet antibodies. Unadsorbed and adsorbed serum samples were crossmatched with ABO-compatible and -incompatible platelets by a radioimmunoassay employing 125I-labeled monoclonal antibodies specific for human gamma, mu, and C3d antigens. IgG and IgM crossmatch incompatibility was directly related to ABO alloantibody titers greater than or equal to 64. The use of adsorbed serum in the crossmatch eliminated or greatly reduced incompatible results that were due to ABO alloagglutinins alone, thus allowing the reliable detection of platelet and/or HLA antibodies.     

Significant numbers of apheresis-derived group O platelet units have "high-titer" anti-A/A,B: implications for transfusion policy

Transfusion of group O single-donor apheresis PLTs (SDP) to group A recipients has resulted in intravascular hemolysis and mortality. Owing to low availability of type-specific SDPs, transfusion services sometimes issue ABO-mismatched PLTs. After observing two cases of acute hemolysis following infusion of O SDPs to group A patients, where both recipient eluates revealed anti-A specificity, a prospective study to determine the prevalence of "high-titer" anti-A/A,B in group O SDPs was commenced. One hundred group O SDP samples were tested. Titers of at least 64 and/or 256 from either buffered (generally reflective of IgM antibodies) or anti-IgG gel cards, respectively, were considered critically high. Twenty-eight and 39 percent of samples revealed critically high anti-A/A,B IgM and IgG titers, respectively. IgM titers were at 1:64 (18%), 128 (6%), and 256 (4%), whereas IgG titers were at 1:256 (28%), 512 (7%), 1024 (2%), and 2048 (2%). The prevalence of critical anti-A/A,B titers in group O SDPs is relatively high. Thus, the risk of minor side ABO mismatch and potential intravascular hemolysis during group O SDP transfusion to group A recipients may be significant. Based on these data, a policy was instituted to test anti-A/A,B titers in O SDPs prior to "out-of-group" transfusion.     

High titers of anti-A1 and anti-B antibodies among Peruvian group O platelet donors

Critical antibody titers have been described as factors associated with hemolysis in ABO plasma-incompatible platelet (PLT) transfusions. This study was carried out to describe the frequency of high-titers anti-A and antiB IgM and IgG antibodies in group O apheresis platelet donors, and to explore differences according to the donor characteristics. A cross-sectional study was carried out at the Blood Bank of a National Hospital in Peru from January to March 2019. IgM and IgG antibodies against A1 and B antigens were quantified in 339 platelet donors using the direct hemagglutination technique and the solid-phase adherence technique, respectively. For analysis purposes, two cut-off points; ≥128 and ≥64, were used to define a critical titer for IgM due to a lack of consensus. An IgG titer of ≥256 was also defined as critical. Of the donors, 22.1 % had critical IgM titers when the cut-off point was defined as ≥128. However, when the IgM cut-off was ≥64, the frequency of platelet donors with critical titers increased to 54.0 %. The frequency of donors with critical IgG titers was 23.5 %. Higher IgG titers were associated with female donors while higher IgM titers were negative associated with age. One in two or three platelet donors, depending on the cutoff point used to define a critical IgM titer, had at least one critical titer of anti-A or anti-B antibodies. Early identification of platelet donors with critical antibody titers could prevent passive transfusion of ABO antibodies to non-isogroup recipients.     

The characteristics of ABO antibodies in group O Thai blood donors

This study aimed to characterize anti-A and anti-B hemolysins, IgM, and IgG titers in Thai blood donors. Altogether, 300 serum samples from group O donors at the National Blood Centre, Thai Red Cross Society, were screened for anti-A and anti-B hemolysins and treated with 0.01 M dithiothreitol to characterize IgM and IgG titers by standard tube technique. Antibody titers were compared with hemolysis grade. Male and female ratio = 1:1.3 and ages ranged from 17 to 60 years. The overall prevalence of anti-A and anti-B hemolysins was 69%. Anti-A and anti-B hemolysins comprised 18.3% and 16.7%, respectively and 34% had both antibodies. High titers of anti-A hemolysins were associated with females (P< 0.05), and only anti-B IgM titers were associated with age (P< 0.05). Interestingly, the association of anti-A IgM titers, anti-A IgG titers, and hemolysin grade was demonstrated (P< 0.05). A significant association between hemolysin grade and anti-B IgM titers was found (P< 0.05). The prevalence of anti-A and anti-B hemolysins and high titers of IgM and IgG in Thais are high. Hemolysin grade showed significant associations with IgM titers; therefore, when providing ABO-incompatible platelet transfusion, especially for female plateletpheresis donors, IgM high titers of anti-A and anti-B screening is suggested.     

Anti-A and anti-A,B monoclonal antisera with high titers favor the detection of A weak phenotypes

ObjectivesThis study aimed to evaluate the reactivity and the titers of commercial anti-A and anti-A,B antisera in the detection of A weak antigen expression in human red blood cells.BackgroundCommercial monoclonal antisera for ABO phenotyping are useful reagents allowing the identification of the four main ABO phenotypes (A, B, AB, and O). However, the reactivity of these commercial reagents can not be evident when the A or B antigens are weakly expressed, and these antisera have low titers.Methods/MaterialsSix samples from blood donors and five samples from patients with ABO forward and reverse discrepant phenotyping were evaluated. The ABO phenotyping was carried out with different commercial monoclonal anti-A and anti-A,B antisera under different temperatures, using test tubes and gel column agglutination.ResultsMonoclonal anti-A antisera with titers less than 256 and anti-A,B with titers less than 128 failed to detect the weak expression of A antigen in 73% and 67% of the A weak phenotypes, respectively. Titres equal to or higher than 2048 (anti-A) and 1024 (anti-A,B) showed better reactivity, independent of the cell clone.ConclusionOur data indicate that anti-A and anti-A,B antisera with high titers give better reactivity with red blood cells carrying A weak antigen expression.     

MB-P对血浆部分细胞因子与ABO血型抗体活性影响

目的研究亚甲蓝光化学病毒灭活法(MB-P)对血浆SCF、TPO、PF4与GPⅡb/Ⅲa活性与ABO血型抗体活性的影响。方法应用ELISA方法对MB-P制备前后血浆SCF、TPO、PF4与GPⅡb/Ⅲa活性进行检测;应用血型血清学检测方法对MB-P制备前后血浆IgM抗-A、IgM抗-B与IgG抗-A、IgG抗-B活性进行检测。结果 MB-P制备血浆SCF、TPO、PF4与GPⅡb/Ⅲa活性均有不同程度下降,分别为2.59±2.71,248.54±49.01,12.02±3.21,10.21±9.97;与制备前相互比较有统计学意义(P0.05)。另外,MB-P制备后血浆红细胞IgM抗-A、IgM抗-B与IgG抗-A、IgG抗-B效价也有不同程度下降,与制备前相互比较有统计学意义(P0.05)。结论应用MB-P制备血浆须高度重视部分细胞因子与红细胞ABO血型抗体变化情况,确保临床输血安全性与有效性。     

新生儿ABO溶血病患儿母亲孕期IgG抗A/B效价的动态监测

目的动态监测O型孕妇不同孕期血清IgG抗A/B效价,为更加准确地预测新生儿ABO溶血病的发生提供诊断依据。方法通过对232例新生儿ABO溶血病的患儿母亲孕早期和孕晚期IgG抗A/B效价的动态监测,观察这类孕妇抗体效价的分布情况、变化率和变化幅度。结果这类孕妇的孕早期和孕晚期IgG抗A/B效价大多分布在≥1∶256,其中绝大多数孕妇（O-A：94.9%,O-B：95.8%）孕晚期的IgG抗A/B效价较孕早期有不同程度的升高;以升高2个滴度为主（O-A：46.3%,O-B：44.8%）。有11例其孕晚期的IgG抗A/B效价较孕早期无变化甚至发生降低,这11例孕妇孕早期的IgG抗A/B效价就偏高,主要分布在≥1∶512。结论动态监测O型孕妇不同孕期血清IgG抗A/B效价十分必要,可以将孕晚期抗体效价较孕早期升高2个滴度或以上作为提示ABO溶血的指标。     

Shigella flexneri O-antigen specific enzyme immunoassay: a prospective study of class-specific antibody titres against lipopolysaccharide antigens in Vietnamese children and adults with serotype 1b or 2a dysentery

A total of 278 sera were collected from 97 patients with a bacteriologically verified Shigella flexneri serotype 1b or 2a infection. Of the patients, 65 were children below the age of 5 years and admitted to the Department of Infectious Diseases at St. Paul's Hospital, Hanoi, Vietnam; 32 were adults, aged 20–24 years, and infected during a dysentery outbreak at Son Tay technical school, Hanoi. The sera were analysed for their specific immunoglobulin A (IgA), M (IgM) and G (IgG) titres against phenol-water-extracted and chemically defined lipopolysaccharide (LPS) antigens of S. flexneri and other shigellae by an enzyme immunoassay (EIA). The titres estimated in sera from patients were compared with titres seen in sera from age-matched healthy people living in the Tu Liem district, Hanoi. Positive titres were defined as greater than the mean titre+ 2 SD in sera from healthy persons. Children 1–2 years old and infected with S. flexneri serotype 1b responded with significantly elevated IgA titres up to 60 days after falling ill (P-values 0·06 to <0·001). The IgG titres against the homologous S. flexneri serotype 1b were significantly elevated in samples collected up to 6 months after children up to 5 years old had fallen ill (P-values ranging from 0·007 to <0·001). IgM titres were elevated, but not significantly higher than those seen in healthy individuals. The results suggested that children younger than 3 years who responded with IgA, IgG and, to a lesser extent, IgM increases were experiencing their first S. flexneri dysentery, whereas older children and adults who only showed IgG increases had had experience with previous S. flexneri infections and displayed an anamnestic response. In adults, significant titre increases were seen only in individuals with low pre-infection titres. The clinical data and laboratory analyses of the strains suggest that a virulent S. flexneri serotype 1b clone was prevalent in the Hanoi area in 1982–1983. Young children infected with S. flexneri serotype 2a also responded with elevated IgA and IgG titres, but there were too few children to permit statistical analyses.     

Antibody response in an ABO-incompatible blood transfusion. Antigen specificity and immunoglobulin class

The anti-A response in a group B patient accidentally given 1 unit transfusion of A1 blood is described. The antibody response is characterized both with conventional agglutination techniques and with radioimmunoassay using pure group A antigens with different core saccharide structures (type 1, 2, and 4 chains) and class-specific second antibodies. The anti-A titer rose to a maximum Days 11 to 14 after the incompatible transfusion. The antibodies involved were mainly of the IgG and IgA types, while the IgM response was moderate. The IgA antibodies seemed to be nonselective with respect to group A antigen type, while the IgG antibodies showed a specificity against type 2 chain group A antigens.     

Antibiodies of the IgG, IgM, and IgA classes in newborn and adult sera reactive with gram-negative bacteria

Umbilical cord serum and adult serum antibodies reactive with heat-stable somatic antigens of Gram-negative bacteria (Neisseria gonorrhoeae, Escherichia coli, and Salmonella typhosa) were assayed by using an indirect fluorescent antibody test. Reactive IgG, IgM, and IgA antibodies were identified by using fluoresceinconjugated antisera specific for these immunoglobulin classes.IgG antibody titers in cord serum approximated those found in the corresponding maternal sera. IgM and IgA antibodies were present in adult sera but were not demonstrable or were present only in small amounts in cord sera. The presence of IgG and IgM antibodies reactive with Gram-negative bacteria was confirmed by the testing of purified 7S and 19S fractions. In addition, both IgG and IgM reactivities were inhibited by the prior incubation of serum with purified specific lipopolysaccharide preparations.The ubiquity and magnitude of these natural IgG antibodies in the sera of both adults and neonates have apparently eluded detection in previous studies. The use of bactericidal and agglutination tests, which are apparently more sensitive to the presence of IgM than to IgG antibodies, may account for the failure of previous studies to detect adult and cord IgG antibodies reactive with somatic antigens of Gram-negative bacteria. The presence of these IgG antibodies may be correlated with the resistance to infection demonstrated by most newborns as they are challenged by the septic extrauterine environment.     

应用ROC曲线评价产前IgG抗A(B)效价检测对早期诊断ABO新生儿溶血病的价值

目的 研究O型孕妇产前血清IgG抗A(B)效价对早期诊断ABO新生儿溶血病(HDN)的价值.方法 采用微柱凝胶法检测704例夫妻血型不同的O型孕妇产前血清IgG抗A(B)效价,用红细胞(RBC)直接抗人球蛋白试验、RBC抗体放散试验、血清游离抗体测定等3项试验确定患儿是否患有HDN,用受试者工作特性(ROC)曲线进行分...     

Utility of an immunocapture-agglutination test and an enzyme-linked immunosorbent assay test against cytosolic proteins from Brucella melitensis B115 in the diagnosis and follow-up of human acute brucellosis

The utility of an immunocapture-agglutination (Brucellacapt, Vircell SL, Granada, Spain) test and an enzyme-linked immunosorbent assay IgG, IgA, and IgM (ELISA-IgG, ELISA-IgA, ELISA-IgM) against cytosolic proteins from Brucella melitensis B115 (R) was compared with ELISA-IgG, ELISA-IgA, and ELISA-IgM against smooth lipopolysaccharide (S-LPS) from B. melitensis 16M (S), serum agglutination test (SAT), and Coombs test in the diagnosis and follow-up for 10 months of 51 patients with acute brucellosis. The sensitivities of ELISA tests against cytosolic proteins varied from 49.0 % for ELISA-IgG to 64.7% for ELISA-IgM and were lower than the sensitivities showed by ELISA S-LPS (from 88.2% to 92.2%), SAT (88.2%), Coombs (96.1%), and Brucellacapt (98.0%) tests. Specificity was over 93% in all cases. The evolutionary behavior of the SAT, Coombs, and Brucellacapt tests was similar. There was a decrease of between 20% and 40% in antibody titer in the 10th month of evolution after treatment. The evolutional curves of IgG, IgA, and IgM against cytosolic protein increased slightly till the eighth month. The specific IgM and IgA antibodies against protein fractions began to show a drop from the eighth month on, showing levels slightly lower than the initial sera values by the end of the 10th month. In this month, titers of specific IgG against proteins fractions remained higher than the titers showed by the initial sera.     

Apheresis therapy for living-donor liver transplantation: experience for apheresis use for living-donor liver transplantation at Kyoto University.

Liver transplantation is a fundamental treatment for patients with end-stage hepatic failure. In order to perform living-donor liver transplantations under safer conditions, apheresis plays a major role in Japan due to the prevalence of living-donor liver transplantation wherein later retransplantation is difficult. In our department, the roles of apheresis in liver transplantation are as follows: as bridge therapy to liver transplantation (n = 45); as a supplement to the graft liver until the recovery of hepatic function (n = 77); as treatment for multiple organ failure including posttransplantation renal failure (n = 15); and as a means with which to reduce antibody titers for antibodies such as anti-A or anti-B in persons with ABO blood type = incompatible liver transplantation (n = 23). In our department, we have performed 822 liver transplantations at present. Of those cases, 183 were selected wherein apheresis was performed around the time of the operation. In all cases, transplantation with sufficient apheresis was performed before the surgical operation, however, 22 patients (48.9%) died after undergoing surgery. Among the patients who underwent the postoperative apheresis, those in the nonsurvivor group had lower grafted liver weights compared to those of the survivor group. The kidney was the organ that most frequently failed due to postoperative complications. In cases of ABO blood type-incompatible liver transplantations, patients with high preoperative anti-A/B IgM antibody titers sustained bile duct complications, patients with high preoperative anti-IgG antibody titers sustained hepatic necrosis, and patients with high postoperative anti-A/B IgM and anti-IgG antibody titers sustained hepatic necrosis most frequently.     

Developmental Patterns of ABO Isoagglutinins in Normal Children Correlated with the Effects of Age, Sex, and Maternal Isoagglutinins

The developmental patterns of ABO saline isoagglutinins were determined in 272 children between birth and 16 years of age. The frequency of saline isoagglutinins was significantly higher in group O-O maternal-cord pairs compared to group A-O paired sera. The anti-A and anti-B titers increased gradually from 3 to 12 months: 30 per cent of group O and B children attained adult median titers of isoagglutinin, whereas only 4 per cent of group A children acquired adult anti-B titers. This slow development of anti-B in group A children persisted through the second year. Maternal isoagglutinins may exert a suppressive influence on the development of specific isoagglutinins in the first year of life.     

Discrepancies in reverse ABO typing due to prozone

Three group O sera manifesting prozone in reverse ABO tests are reported. All were implicated in erroneous blood typing results. One sample failed to react with A1 red cells (RBCs) in immediate-spin (IS) tests, had anti-A and -B titers of 8192 and 2048, respectively, by indirect antiglobulin technique (IAT), and was from a diabetic patient; the parenteral administration of A substance present in porcine insulin is a possible cause of hyperimmunity in this case. The second sample was from the recipient of a single unit of group B fresh-frozen plasma; the serum anti-A and -B titers were 10,240 by IAT, but only weak reactions with A1 and B RBCs were noted in routine IS reverse typing tests; the hyperimmunity in the patient concerned was likely due to crossreacting anti-A, B stimulated by B-active glycoproteins and/or glycolipids in the transfused plasma. The third serum also had anti-A and anti-B IAT titers of 10,240 but did not react with A1 and B RBCs by IS; the hyperimmunity in this case may be related to sepsis from intestinal flora carrying A- and/or B-like antigens. These antibodies lysed A1 and/or B RBCs in tests incubated at room temperature (RT) and strongly agglutinated those RBCs by IS when diluted 10-fold with saline. The absence of the prozone phenomenon in tests with RBCs suspended in diluents containing EDTA is consistent with the previously published mechanism for anti-A prozone: namely, the steric hindrance of agglutination by the C1 component of human complement.(ABSTRACT TRUNCATED AT 250 WORDS)     

Some observations on "Bombay" bloods, with comments on evidence for the existence of two different Oh phenotypes

Bloods from three individuals, one each of the phenotypes Oh-A, Oh-B and Oh-O have been studied. The work of Dzierzkowa-Borodej, et al.-10 was confirmed when it was shown that all three samples of Oh red blood cells had increased I antigen strength. The i, Sd-a, Le-a and Le-x antigens were not found to be increased. Attempts were made to adsorb and elute anti-A, anti-B and anti-A,B with the Oh red blood cells, using sera that contained high titered anti-I antibodies. This was done in the belief that previously reported positive results in such tests might be due to the high level of I on the Oh red blood cells, anti-I in the sera containing the ABO antibodies, and the Matuhasi-Ogata phenomenon. However, in no instance were we able to adsorb an ABO antibody onto the Oh red blood cells. Contrary to the report of others- 10 the titers of anti-A, anti-B and anti-H in the sera of the three Oh individuals studied did not differ significantly. We suggest that the evidence from our findings and the work of others is sufficient to show that at least two forms of the Oh phenotype exist: one representing total suppression of H, A, and B antigens, and the other marked but not total suppression, with partial inhibition of antibody production.     

Serological response to plasmid-encoded antigens in children and adults with shigellosis

The immunological response to plasmid-encoded antigens of virulent Shigella was determined in Thai children less than 4 yr of age and in Thai adults by immunoblot analysis and ELISA. Forty-two percent (8/19) of Thai children and 4% (1/22) of Thai adults with shigellosis developed a greater than or equal to 4-fold rise in IgG antibody titer to water-extracted antigens of Shigella flexneri M90T by ELISA (p = 0.006). Two children and one lactating mother with shigellosis developed a 4-fold rise in serum IgA antibody titers to water-extracted antigens of M90T. The results of the ELISA were confirmed by immunoblot analysis in all of the 41 paired sera examined. Five patients developed IgA, and four developed IgM, antibodies as detected by immunoblot analysis, that were not detected by ELISA. The reciprocal log2 geometric mean titers of antibodies to plasmid-encoded antigens in acute sera was higher in Thai adults than Thai children: IgG 7,265 versus 1,659; IgM 879 versus 480; and IgA 662 versus 60 (p less than 0.001). Thai adults had high titers of antibodies to plasmid-encoded antigens in their acute sera, but were susceptible to Shigella infections, although they were historically less susceptible than Thai children.