Neonatal hemolytic disease: How should we use indirect and direct antiglobulin tests?

BACKGROUND

In newborns with hemolysis, the direct antiglobulin test (DAT) and indirect antiglobulin test (IAT) play a key role in demonstrating the presence of an immune cause. We aimed to emphasize the importance of IAT in mothers of DAT-positive babies.

METHODS

DAT was performed with forward blood grouping on cord blood in term babies who were born between September 2020 and September 2022. IAT was performed in the mothers of the babies who were found to have a positive DAT and antibody identification was performed in the mothers who were found to have a positive IAT. Specific antibodies detected and identified were associated with the clinical course.

RESULTS

The study included 2769 babies and their mothers. The prevalence of DAT positivity was found to be 3.3% (87 of 2661). In DAT-positive babies, the rate of ABO incompatibility was 45.9%, the rate of RhD incompatibility was 5.7% and the rate of RhD and ABO incompatibility in association was 10.3%. The rate of subgroup incompatibility and other red blood cell antibodies was 18.3%. Phototherapy was applied because of indirect hyperbilirubinemia in 16.6% of the DAT-negative babies and in 51.5% of the DAT-positive babies. The need for phototherapy was significantly higher in DAT-positive infants (p < 0.01). Severe hemolytic disease of the newborn, bilirubin level, duration of phototherapy and use of intravenous immunoglobulin were found to be significantly higher in the babies whose mothers were IAT positive compared with the babies whose mothers were IAT negative (p < 0.01).

CONCLUSIONS

IAT should be performed on all pregnant women. When screening with IAT is not performed during pregnancy, performing DAT in the baby plays a key role. We showed that the clinical course was more severe when mothers of DAT-positive babies were IAT positive.

ABO hemolytic disease of the newborn: a need for clarity and consistency in diagnosis

The diagnosis of ABO hemolytic disease of the newborn (ABO HDN) has been the subject of considerable debate and clinical confusion. Its use as an overarching default diagnosis for hyperbilirubinemia in all ABO incompatible neonates regardless of serological findings is problematic and lacks diagnostic precision. Data on hemolysis indexed by carbon monoxide (CO) levels in expired air (ETCOc) and blood (COHbc) support an essential role for a positive direct antiglobulin test (DAT) in making a more precise diagnosis of ABO HDN. A working definition that includes ABO incompatibility, significant neonatal hyperbilirubinemia, and a positive DAT is needed to gain clarity and consistency in the diagnosis of ABO HDN. Absent a positive DAT, the diagnosis of ABO HDN is suspect. Instead, a negative DAT in a severely hyperbilirubinemic ABO incompatible neonate should trigger an exhaustive search for an alternative cause, a search that may require the use of targeted gene panels.

Creating Options for Difficult-to-match Kidney Transplant Candidates

BACKGROUND

Most transplantation centers recognize a small patient population that unsuccessfully participates in all available, both living and deceased donor, transplantation programs for many years: the difficult-to-match patients. This population consists of highly immunized and/or ABO blood group O or B patients.

METHODS

To improve their chances, Computerized Integration of Alternative Transplantation programs (CIAT) were developed to integrate kidney paired donation, altruistic/unspecified donation, and ABO and HLA desensitization. To compare CIAT with reality, a simulation was performed, including all patients, donors, and pairs who participated in our programs in 2015-2016. Criteria for inclusion as difficult-to-match, selected-highly immunized (sHI) patient were as follows: virtual panel reactive antibody >85% and participating for 2 years in Eurotransplant Acceptable Mismatch program. sHI patients were given priority, and ABO blood group incompatible (ABOi) and/or HLA incompatible (HLAi) matching with donor-specific antigen-mean fluorescence intensity (MFI) <8000 were allowed. For long-waiting blood group O or B patients, ABOi matches were allowed.

RESULTS

In reality, 90 alternative program transplantations were carried out: 73 compatible, 16 ABOi, and 1 both ABOi and HLAi combination. Simulation with CIAT resulted in 95 hypothetical transplantations: 83 compatible (including 1 sHI) and 5 ABOi combinations. Eight sHI patients were matched: 1 compatible, 6 HLAi with donor-specific antigen-MFI <8000 (1 also ABOi), and 1 ABOi match. Six/eight combinations for sHI patients were complement-dependent cytotoxicity cross-match negative.

CONCLUSIONS

CIAT led to 8 times more matches for difficult-to-match sHI patients. This offers them better chances because of a more favorable MFI profile against the new donor. Besides, more ABO compatible matches were found for ABOi couples, while total number of transplantations was not hampered. Prioritizing difficult-to-match patients improves their chances without affecting the chances of regular patients.

A comparison of desensitization methods: Rituximab with/without plasmapheresis in ABO-incompatible living donor liver transplantation

BACKGROUND

Plasmapheresis is a desensitization method used prior to ABO-incompatible (ABO-I) living donor liver transplantation. However, studies on its usefulness in the rituximab era are lacking.

METHODS

Fifty-six adult patients underwent ABO-I living donor liver transplantation between January 2012 and October 2015. A single dose of rituximab (300 mg/m²) was administered 2 weeks before surgery with plasmapheresis in all patients until February 2014 (RP group, n = 26). Patients were administered rituximab only, without plasmapheresis between March 2014 and October 2015 (RO group, n = 30).

RESULTS

The 6-, 12- and 18-month overall survival rates were 92.3%, 80.8% and 76.9% in the RP group and 96.6%, 85.4% and 85.4% in the RO group, respectively (P = 0.574). When the initial isoagglutinin titers < 16, neither group showed a rebound rise of isoagglutinin titers. For patients with initial isoagglutinin titers ≥ 16, the rebound rise of isoagglutinin titers was more prominent in the RP group. There was no difference in time-dependent changes in B cell subpopulations and ABO-I-related complications.

CONCLUSIONS

Sufficient desensitization for ABO-I living donor liver transplantation can be achieved using rituximab alone. This desensitization strategy does not affect the isoagglutinin titers, ABO-I-related complications and patient survival.

Pediatric Heart Transplantation across ABO Blood Type Barriers: A Case Study

Heart transplantation with ABO blood type–incompatible donors has historically been contraindicated because of the high risk of an immediate hyperacute humoral graft rejection. The immature neonatal immune system presents an immunologic window that allows for breaching the ABO barrier before the natural development of anti-ABO antibodies. Information from a small series of neonates has demonstrated similar survival rates and posttransplant outcomes compared to ABO-compatible transplantations. In the posttransplant period, particular attention is placed on the surveillance of graft-specific antibody production and monitoring for immunologic signs and symptoms of early graft vasculopathy. This article presents a case study of a neonate with congenital heart disease who underwent one of the first successful ABO-incompatible heart transplantations in the United States.

Precautions surrounding blood transfusion in autoimmune haemolytic anaemias are overestimated

BACKGROUND

It is very evident that many precautions are taken regarding transfusion of red blood cells in patients with autoimmune haemolytic anaemia. Frequently, considerable efforts are made to examine the indication and serological compatibility prior to transfusion in such patients. However, at times, this may unnecessarily jeopardize patients who urgently require a red blood cell transfusion.

MATERIALS AND METHODS

Thirty-six patients with warm-type autoimmune haemolytic anaemia were included in this study. All patients had reactive serum autoantibodies and required blood transfusion. Standard serological assays were employed for the detection and characterization of antibodies to red blood cells.

RESULTS

A positive direct antiglobulin test was observed in all 36 patients, in addition to detectable antibodies in both the eluate and serum. Significant alloantibodies were detected in the serum samples of three patients (anti-c, anti-JK(a), and anti-E). In 32 patients, red blood cell transfusion was administered with no significant haemolytic transfusion reactions due to auto- and/or allo-antibodies. Due to overestimation of positive cross-matches three patients received no transfusion or delayed transfusion and died, and one patient died due to unrecognised blood loss and anaemia which was attributed to an ineffective red blood cell transfusion.

DISCUSSION

Many of the reported recommendations regarding transfusion of red blood cells in autoimmune haemolytic anaemia are highly questionable, and positive serological cross-matches should not result in a delay or refusal of necessary blood transfusions.

Efficacy and safety of tandem hemodialysis and immunoadsorption to desensitize kidney transplant candidates

OBJECTIVES

We conducted a desensitization program in our center in patients undergoing kidney transplant for end-stage renal disease. These patients had a living-donor either ABO incompatible and/or human-leukocyte antigen-incompatible. The safety and efficacy of this program were evaluated.

MATERIALS AND METHODS

A pretransplant desensitization program relies on immunosuppressants and apheresis to remove detrimental antibodies. We chose immunoadsorption as the apheresis technique, and coupled this with hemodialysis in a tandem procedure.

RESULTS

We report on the efficacy of this new method in 120 procedures performed in 20 patients (14 ABO incompatible, 6 ABO incompatible/human leukocyte antigen-incompatible). The tandem procedure was well tolerated, and saved time compared with conducting sequential immunoadsorption and hemodialysis (6 h vs 10 h). The tandem procedure was associated with significantly decreased isoagglutinin titers and donor-specific alloantibodies (assessed by mean fluorescence intensity). Dialysance was effective (183, 102-264). The biochemical and hematologic parameters were similar to those observed after a conventional hemodialysis session, with the exception of protidemia; this might be related to some degree of albumin loss during the immunoadsoprtion procedure. The posttransplant events included 1) one ABO incompatible / human leukocyte antigenincompatible patient with vein thrombosis and ultimate kidney loss; 2) two patients with steroidsensitive cellular acute rejection; and 3) two patients with acute antibody-mediated rejection, which was successfully treated with apheresis and steroid pulses, plus rituximab in one and eculizumab in the other.

CONCLUSIONS

We conclude that the tandem immunoadsorption-hemodialysis procedure is efficient at desensitizing patients with end-stage renal disease who are candidates for a living ABO incompatible and/or human leukocyte antigenincompatible donor-kidney transplant.

Trends in ABO-incompatible kidney transplantation

The ABO-incompatible living-donor kidney transplantation was developed in Japan in 1989. Currently, most transplant physicians and surgeons have noted that outcomes are unexpectedly excellent, and no hyperacute rejections have been reported since 2001. In the registry of the Japanese ABO-Incompatible Kidney Transplantation Committee, the data of 2434 ABO-incompatible living-donor kidney transplants were collected from 120 Japanese kidney transplant centers. Overall patient and graft survival rates were 97% and 94% at 1 year, 93% and 86% at 5 years, 90% and 71% at 10 years, and 73% and 52% at 20 years. The patient survival and graft rates in 2001 to 2012 were 93% and 81%, which were significantly better than 83% and 55% reported in 1989 to 2000. The addition of novel immunosuppressive treatments has improved results. Azathioprine has been replaced by mycophenolate mofetil since 2000 to 2001, and basiliximab and rituximab were introduced in 2002 and 2004. The titer of antidonor blood group antibody before transplantation was not correlated with graft survival in 2001 to 2012. De novo antibodies against vascular endothelium of peritubular and glomerular capillaries seemed to be more important than natural antibodies against red blood cells. Therefore, recipients with antidonor blood group antibody titers < 1:128 did not require antibody-removal procedures such as plasmapheresis or immunoadsorption. In particular, children (regard less of their peritoneal dialysis status) do not need to be catheterized for plasmapheresis or immunoadsorption. It is better to avoid the risks of catheterization and antibody removal procedures in children with end-stage renal failure.

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA

OBJECTIVE

Anti-D immunoglobulin is applied to all pregnant women having RhD incompatibility to prevent hemolytic disease of the newborn. The aim of this study is to determine fetal RhD status in the Rh incompatible pregnancies with an non-invasive technique; free fetal DNA isolation from maternal circulation. In the case of Rh incompatibility especially with a history of previous fetal anemia, it can be beneficial to know Rh status antenatally in terms of monitoring fetuses with Rh positive [RhD(+)] status consciously.

MATERIALS AND METHODS

Total free DNA was isolated in 50 Rh negative [RhD(-)] pregnant women, who had RhD alloimmunisation with their husbands. The gene in isolated DNA was investigated with TagMan prob and real time PCR by using primers belonging to exon 7 of the RhD gene.

RESULTS

The authors analyzed 50 RhD(-) women by using quantitative real time PCR technique. Five of them were RhD(-) and the rest of them were found to be RhD(+). After birth one of the infants who were analyzed as RhD(+) were found to be RhD(-).

CONCLUSION

The detection of fetal RhD status by using a non-invasive method from maternal circulation was found to be possible. Assessing fetal RhD status non-invasively by using free fetal DNA in maternal blood will be cost-efficient, avoiding unnecessary indirect Coombs test and unnecessary Rhogam applications that is used in RH incompatible pregnancies. This study will throw a fresh light on prenatal diagnosis.

Feline blood genotyping versus phenotyping, and detection of non-AB blood type incompatibilities in UK cats

OBJECTIVES

The aim of this study was to determine the agreement between AB blood phenotyping and genotyping and determine whether non-AB blood type incompatibilities exist in UK cats.

METHODS

Blood samples underwent phenotyping (A, B or AB) using microplate agglutination, and genotyping (AA, Ab or bb) using pyrosequencing of a fragment of the cytidine monophospho-N-acetylneuraminic acid hydroxylase gene. Non-AB blood type incompatibilities were investigated by cross-matching against reference blood of the same phenotype.

RESULTS

Of 112 cats tested, 86 (77%) were blood phenotype A, 19 (17%) type B and 7 (6%) type AB. Genotype and initial phenotype agreed in 96% (107 of 112) of cats, but 5 were discordant; these were all B phenotype with either AA (n=2) or Ab (n=3) genotype. Two of the five cats had repeat blood samples tested: one was reclassified as phenotype A; the other remained phenotype B. Two cats had incompatibilities on minor cross-match, but these were attributed to phenotyping errors.

CLINICAL SIGNIFICANCE

Unknown mutation(s) associated with phenotype B, resulting in false AA or Ab genotyping, were evident in a small number of cases in this study. No conclusive evidence for non-AB blood type incompatibilities was found.

[Sickle cell anemia and transfusion safety in Bamako, Mali. Seroprevalence of HIV, HBV and HCV infections and alloimmunization belonged to Rh and Kell systems in sickle cell anemia patients]

Red cell transfusion is one of the main treatments in sickle cell disease. However there are potential risks of blood transfusions. In order to propose strategies to improve blood safety in sickle cell disease in Mali, we conducted a prospective study of 133 patients with sickle cell anemia recruited at the sickle cell disease research and control center of Bamako, November 2010 to October 2011. The study aimed to determine the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections by serum screening and the frequency of red cell alloimmunization before and after blood transfusion. The diagnosis of sickle cell syndrome was made by HPLC, the detection of markers of viral infection was performed by ELISA, and the diagnosis of alloimmunization was conducted by the Indirect Coombs test. Prevalence of viral infections observed at the time of enrolment of patients in the study was 1%, 3% and 1% respectively for HIV, HBV and HCV. Three cases of seroconversion after blood transfusion were detected, including one for HIV, one for HBV and one another for HCV in sickle cell anemia patients. All these patients had received blood from occasional donors. The red cell alloimmunization was observed in 4.4% of patients. All antibodies belonged to Rh system only. Blood transfusion safety in sickle cell anemia patients in Mali should be improved by the introduction of at least the technique for detecting the viral genome in the panel of screening tests and a policy of transfusions of blood units only from regular blood donors.

ABO antibody titers are not predictive of hemolytic reactions due to plasma-incompatible platelet transfusions

BACKGROUND

The overall risk of hemolytic transfusion reactions (HTRs) from plasma (minor)-incompatible platelet (PLT) transfusions and the role of a critical anti-A or anti-B titer in predicting and preventing these reactions has not been clearly established.

STUDY DESIGN AND METHODS

We evaluated all apheresis PLT (AP) transfusions for 3 months. Using the gel titer method, we determined the anti-A and/or the anti-B immunoglobulin (Ig)G titer for all incompatible APs. Reported febrile transfusion reactions and HTRs were recorded; transfusions were not prospectively evaluated by the study team. A posttransfusion direct antiglobulin test (DAT) and eluate were performed after a reported febrile or hemolytic reaction for patients who received plasma-incompatible APs.

RESULTS

A total of 647 of 4288 AP transfusions (15.1%) were plasma incompatible. Group O APs (n = 278) had significantly higher anti-A and anti-B titers than group A or B APs (p < 0.0001). No group A or B APs had a titer of more than 128 (0/342). For group O APs, 73 had titers of 256 or greater (26.3%), and 27 had titers of 512 or greater (9.7%). No HTRs were reported to any plasma-incompatible AP transfusion during the study period. Two plasma-incompatible AP transfusions were associated with fever and chills and positive DATs, of which one had a positive eluate. The incidence of a DAT and eluate-positive febrile transfusion reaction in the plasma-incompatible AP population is 0.15% (95% confidence interval, 0.0%-0.86%).

CONCLUSION

A critical anti-A or -B titer is not sufficient to predict the risk of hemolysis in patients receiving plasma-incompatible APs, although underreporting of reactions to the blood bank may limit the generalizability of this study.

Early detection of a blood transfusion reaction utilizing a wireless remote monitoring device

Continuously monitoring vital signs on general care units may provide earlier detection and intervention of instabilities in patients. These earlier interventions could prevent deaths and admission to critical care units, thereby increasing patient safety and improving patient outcomes.

DNA-based methods in the immunohematology reference laboratory

Although hemagglutination serves the immunohematology reference laboratory well, when used alone, it has limited capability to resolve complex problems. This overview discusses how molecular approaches can be used in the immunohematology reference laboratory. In order to apply molecular approaches to immunohematology, knowledge of genes, DNA-based methods, and the molecular bases of blood groups are required. When applied correctly, DNA-based methods can predict blood groups to resolve ABO/Rh discrepancies, identify variant alleles, and screen donors for antigen-negative units. DNA-based testing in immunohematology is a valuable tool used to resolve blood group incompatibilities and to support patients in their transfusion needs.

Performance of an automated solid-phase red cell adherence system compared with that of a manual gel microcolumn assay for the identification of antibodies eluted from red blood cells

IgG antibodies coating red blood cells (RBCs) can be removed by elution procedures and their specificity determined by antibody identification studies. Although such testing is traditionally performed using the tube agglutination assay, prior studies have shown that the gel microcolumn (GMC) assay may also be used with comparable results. The purpose of this study was to compare an automated solid-phase red cell adherence (SPRCA) system with a GMC assay for the detection of antibodies eluted from RBCs. Acid eluates from 51 peripheral blood (PB) and 7 cord blood (CB) samples were evaluated by both an automated SPRCA instrument and a manual GMC assay. The concordance rate between the two systems for peripheral RBC samples was 88.2 percent (45 of 51), including cases with alloantibodies (n = 8), warm autoantibodies (n = 12), antibodies with no identifiable specificity (n = 2), and negative results (n = 23). There were six discordant cases, of which four had alloantibodies (including anti-Jka, -E, and -e) demonstrable by the SPRCA system only. In the remaining 2 cases, anti-Fya and antibodies with no identifiable specificity were demonstrable by the GMC assay only. All seven CB specimens produced concordant results, showing anti-A (n = 3), -B (n = 1), maternal anti-Jka (n = 2), or a negative result (n = 1). Automated SPRCA technology has a performance that is comparable with that of a manual GMC assay for identifying antibodies eluted from PB and CB RBCs.