Age dependency of ABO histo-blood group antibodies: reexamination of an old dogma

Current textbooks for transfusion medicine state that anti-A and/or anti-B (anti-A/B) agglutination titers–and thus the respective antibody concentrations–reach their maximum in individuals 5 to 10 years old and then gradually decline with the increasing age of the individual. This statement is largely based on a study by Thomsen and Kettel that dates to 1929. In the present article, ABO antibodies in sera of 175 healthy persons aged 61 to 97 years, as well as sera of 170 newborn infants and children aged 0 to 17 years, were analyzed. Microhemagglutination tests were performed with all sera and complemented by ABO enzyme-linked immunosorbent assays to measure the immunoglobulin class (IgM, IgG, and IgA) of the anti-A/B. As in a previous study using sera of persons aged 20 to 67 years, individual differences exceeded age-related changes for all variables. Median values of IgG and IgA anti-A/B were elevated in elderly persons of blood group O, whereas no significant changes were observed in other variables. In particular, the decrease in agglutination titers with the increasing age of the individuals was far less pronounced than previously described; even in sera of persons aged 90 to 97 years, median agglutination titers of 128 were found. Results in the sera of children confirm previously reported data that agglutination titers and IgM anti-A/B reached adult levels at the age of 5 to 10 years.     

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。     

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.     

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。     

ABO新生儿溶血病与O型孕妇血清中IgG及其亚类含量的相关分析

目的探讨O型孕妇血清IgG抗体及其亚型含量与新生儿溶血病(HDN)的关系。方法采用血型血清学方法,对317名夫妇血型不合的O型孕妇作IgG抗体效价检测,并对其中有妊娠史的287名孕妇作IgG抗体水平比较;采用ELISA法对71名HDN患儿及其母亲、65名健康O型孕妇和51名健康新生儿的IgG亚类作定量分析。结果1)317名新生儿中发生ABOHDN71例(22.4%),其中抗-A46例、抗-B25例;2)随着妊娠次数的增加,IgG抗体效价≥64者的比例和ABO-HDN发病率升高,>2次妊娠与第2次妊娠间有统计学差异;3)患儿及其母亲体内IgG抗体的含量显著高于正常对照组,且以IgG1抗体为主,患儿体内的IgG1比例(61.9%)高于母体(52.8%)。结论新生儿ABOHDN的发病率随其母亲体内IgG抗体效价的升高而升高,且与母亲体内IgG1呈正相关。夫妇血型不合的O型孕妇应定期检测IgG抗体及其亚类含量。     

Natural antibodies in sera of patients with systemic lupus erythematosus

Sera obtained from fifty-five patients with active systemic lupus erythematosus (SLE) and from four patients with mixed connective tissue disease (MCTD) previously shown by immunofluorescence and by double immunodiffusion to possess antinuclear antibodies, were tested for the presence of natural antibodies of IgG, IgA, and IgM isotypes. Antibody activity to actin, myosin, DNA, TNP, albumin, and tubulin was examined, using an enzyme-linked immunosorbent assay (ELISA). It was found that, in comparison with the antibody titers in normal sera, most of the SLE and MCTD sera possessed statistically greater amounts of IgG, IgA, and IgM antibodies directed against all the antigens tested. Furthermore, the IgG, IgA, and IgM antibody activity to DNA and TNP, compared to that found with all the other antigens, was significantly higher. Antibodies reacting with a saline extract of calf thymus (ECT) were studied by ELISA and by immunodiffusion. No correlation was observed between the natural antibody titers and the serum antibody levels to ECT detected either by ELISA or by immunodiffusion.     

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。     

Comparison between the levels of anti-A/B IgM/G antibodies in paired mother/child serum samples

A relationship between the anti-A/B ABO-histoblood group antibody levels was investigated in the serum samples of 24 mother/child pairs of which 16 were ABO-identical, 2-compatible and 6-incompatible. For this purpose, and in addition to conventional haemagglutination technology, we used a novel ELISA system which involves synthetic trisaccharides coupled to bovine serum albumin as capturing antigens. Development of the ELISA with isotype-specific monoclonal anti-IgM/G antibodies further allows for quantitative estimation of anti-A/B IgM/G in serum samples. In maternal serum samples, the correlation assessed by Spearman's rank correlation test was significant between anti-A haemagglutination titre and anti-A IgM as quantitated by ELISA (r_s = 0.837, P < 0.001). In addition, comparison between anti-B IgG level in maternal and neonatal serum samples revealed a significant correlation (r_s = 0.720, P < 0.001) reflecting transplacental passage of the IgG molecules. Hyperbilirubinemia was seen in 3 neonates independently of the ABO constellation between mother and child. The six incompatible children had birth weights corresponding to their degree of maturity. In this category, three children were born preterm and three at maturity. Although on the basis of these data a transplacental crossing of IgG isotype anti-A/B antibodies takes place indeed, this process on its own is not sufficnent to cause haemolytic disease of the newborn.     

Studies on IgA class circulatory red cell antibodies--I. Preparation and identification of IgA class anti-A,anti-B

To elucidate the role of IgA class alloantibodies in transfusion practice, anti-A,anti-B was prepared using pooled serum from healthy group O donors. IgG was removed by protein A and protein G, whilst IgM was extracted by concanavalin A and anti-human mu chain. The final preparation contained both IgA1 and IgA2; it had an IgA concentration similar to the original serum pool and an environment as near to normal as possible; the absence of IgG and IgM was confirmed by sensitive enzyme-linked antiglobulin tests, and extensive haemagglutination studies showed that anti-A,anti-B was the only red cell antibody present.     

Class- and subclass-specific antibody response to hemocyanin in nonmalignant paraproteinemia.

IgM, IgG, and IgA class-specific, as well as IgG subclass-specific antibody titers against the primary immunogen HPH were measured with ELISA in 19 patients with nonmalignant paraproteinemia (eight with IgG1, two with IgG2, two with IgG4, four with IgM, and three with IgA) and in a simultaneously studied age- and sex-matched control group. After primary immunization only IgM and IgA anti-HPH titers were significantly lower in the patient group. Four patients with relatively high IgG or IgA serum paraprotein levels did not produce antibodies in some Ig classes or IgG subclasses, whereas all other patients and all controls developed antibody titers in all classes and IgG subclasses. Low or absent antibody titers did not occur preferentially in the Ig (sub)classes to which the paraproteins belonged. After secondary immunization the patients could not increase or maintain their antibody titers as well as the controls, and this was most clear in the IgM and IgA antibody class. A direct correlation between polyclonal serum IgM levels and IgM anti-HPH titers was present in the patients. Such a correlation was absent for IgA in the patients and for all classes in the controls. It is concluded that humoral immunosuppression as measured with a newly encountered antigen in patients with nonmalignant paraproteinemia is most clearly expressed in the IgM and IgA antibody class and that the paraprotein (sub)class is not preferentially involved.     

Rapid quantitation of immunoglobulin G antibodies specific for blood group antigens A and B by surface plasmon resonance

BACKGROUND: The measurement of immunoglobulin (Ig) G blood group A/B antibody(anti-A/B) levels is important for ABO-unmatched organ recipients because the effective removal of the antibodies improves their prognosis. Currently existing methods to detect IgG anti-A/B suffer limitations owing to high costs, low throughput, and poor adaptability to automation. STUDY DESIGN AND METHODS: We have developed a rapid means to quantitate IgG anti-A/B by surface plasmon resonance (SPR). To investigate the accuracy, a serially diluted plasma sample from a donor was measured with the SPR method. Moreover, IgG anti-A/B titers in 45 healthy volunteers were measured both by the SPR and by the standard tube test (TT) method, as were plasma samples from two ABO-unmatched organ recipients. RESULTS: The change in titers when the same plasma was diluted was precisely reflected by the SPR method. The coefficients of correlation between SPR and TT methods for IgG anti-A and anti-B were 0.85 and 0.56, respectively. The SPR values also paralleled the TT values, which showed a decline in titers after the removal of antibodies by double-filtration plasmapheresis or plasma exchange. CONCLUSION: This SPR method can be used to measure IgG anti-A/B titers in the plasma very quickly and quantitatively.     

人血液经56℃孵育处理后溶血率及血型抗原抗体变化

目的 为降低传染风险,对疑似或确诊新型冠状病毒(SARS-Cov-2)患者血样,部分实验室采用56℃孵育30分钟后再进行血型血清学检测,该处理方法对输血前检测的影响未见评估研究.本研究对血液样本经56℃孵育后的溶血率、红细胞A、B、D抗原凝集强度及其抗体效价进行评估.方法 从上海地区随机抽取正常献血者A型20例,B型2...     

Blood group isoagglutinins and immunoglobulins (IgG, IgM) in old age

Titres of blood-group isoagglutinins and the serum concentration of immunoglobulins M and G were investigated in 388 inmates (89.7% females) of an old-age home, ranging in age from 78 to 99 years [mean (+/- s) = 85.7 years +/- 4.1 years]. Concentrations of isoagglutinins were positively correlated to the concentrations of IgM (total concentration of IgM corr. to IgM anti-B (group A): p less than 0.0005, corr. to IgM anti-A (group B): p less than 0.01, corr. to IgM anti-B (group 0): p less than 0.025), but not to the concentration of IgG. The blood group A IgG red cell alloantibodies (IgG anti-B) indicated, in the low titre range, a positive correlation (p = 0.025) to the IgM isohaemagglutinins (IgM anti-B); the red cell alloantibodies (IgG, IgM) of the other blood groups did not correlate in this way. There was no age-dependent reduction or increase in isohaemagglutinin titres and/or total immunoglobulin levels. From these date we conclude that the lack of red cell alloantibodies in the serum of elderly patients in case of routine ABO blood grouping should not be accepted any more. There has to be an internal diagnosis available or, if missing, coinciding diagnostic tests should be performed.     

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.     

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.     

Preparation of single donor platelet with low antibody titers for all patients

Platelet concentrates from ABO-identical donors are the components of choice for patients. However, since inventories are generally insufficient and because there is usually a relative abundance of group O donors, perfect matches are not always possible. It is therefore the accepted practice for platelets to be transfused out of the ABO group when ABO-identical platelets are unavailable. Notwithstanding, the transfusion of platelets containing high titers of antibodies to the antigens on the red blood cells of the patient can cause clinically significant hemolysis. The way to improve the safety of group O platelets has focused on defining a safe level of antibodies or reducing the volume of incompatible plasma. In the current study, 107 group O single donor platelets (SDP) were modified after collecting the platelet pellet in a bag. The AB plasma was added instead of the donor's own plasma. The direct agglutination titers of anti-A/anti-B in the original group O SDPs' plasma were performed by doing a gel test, resulting in from 1:4 to 1:1024. The prevalence of high titers (i.e., at least 1:64 in our study) was relatively high, ～63% for anti-A and 78% for anti-B. The titer of residual anti-A/anti-B in the modified SDPs ranged from negative to 1:8. In most of the modified SDPs anti-A/anti-B could not be detected in the plasma (58.9% and 52.3%, respectively). The results indicate that our modified SDPs have very low titers; that is, acting as a universal SDP which is safe for all ABO patients. This modified SDP form is a more convenient way to overcome the risk from incompatible plasma or loss of platelets during the process of volume reduction and can help effectively manage our inventory.     

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.     

ABO antibody titer performance characteristics and correlates between two automated platforms

BackgroundAABB standards require a policy for assessing transfusing ABO-incompatible plasma. After a fatal hemolytic event with incompatible plasma, our institution instituted platelet donor population titer method for ABO antibodies on the PK7300, with high-titer being defined as having isohemagglutinin titers greater than 256. We recently switched titering platforms to the Neo Iris and we seek to determine the equivalent isohemagglutinin high-titer cutoff on the Neo Iris as compared to the PK7300.MethodsWe measured the titers on 299 apheresis platelet donors and compared its performance characteristics at various cutoffs to the PK7300 reference standard. Discrepant results were manually diluted and retested on the Neo Galileo. Furthermore, since the Neo Iris is able to determine isotype and antigen specific titers, we also characterized these features in our donor population.ResultsIgM titer of 128 on the Neo Iris has better accuracy compared to the titer of 64 (94 % vs 93.6 %). Eleven of sixteen discordant results were in agreement with Neo Iris. Blood group O had the highest IgG antibody titers for both anti-A and anti-B (p = 8.4E-17 and 4.3E-09, respectively). Additionally, group O donors exhibited lower anti-A2 than anti-A1 IgG titers.DiscussionThe Neo Iris titer cut-off of 128 had the best overall accuracy and correlation with a 256 cut-off on our laboratory developed test on the PK7300 platform. Additionally, we found that group O donors had the highest titer antibodies, with typically higher IgG titers than IgM, and generally multiple dilution levels greater than other blood types.     

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.