Is it necessary to add the eluate testing to the direct antiglobulin test to improve the detection of maternal erythrocyte alloantibodies?

BACKGROUND: The screening of umbilical cord blood samples by the Direct Antiglobulin Test (DAT) is the reference tool for the identification of maternal erythrocyte alloantibodies present in erythrocytes; however, its diagnostic usefulness is controversial. OBJECTIVE: To evaluate the diagnostic validity, safety, and efficiency of the eluate testing (detection of antibody in erythrocyte eluates by the Indirect Antiglobulin Test/IAT) in cord blood samples for detection of maternal erythrocyte alloantibodies in comparison with the DAT. MATERIALS AND METHODS: Evaluation study of diagnostic tests. DAT and eluate testing were performed in 306 cord blood samples from neonates born to mothers admitted at Clínica Somer in Rionegro, Colombia; then, antibodies present in the eluates were identified with erythrocyte panels. Percentage of positive results by DAT and IAT were compared with the Pearson's chi-square test and the agreement between both assays with the Cohen's kappa coefficient. The diagnostic sensitivity, specificity, safety, and efficiency of the eluate testing were calculated, taking into account the use of DAT as an imperfect reference test. RESULTS: The DAT detected alloantibodies in 6.21% of samples and the eluate testing in 14.1 %; the strength of agreement between both tests was moderate (k = 0.56) due to 25 discrepancies. The eluate testing showed sensitivity and specificity of 98.83 % and 92.31 % respectively, and a negative predictive value of 99.9 %. The diagnostic efficiency was sufficient for detection of maternal erythrocyte alloantibodies. The antibodies identified in the erythrocyte eluates were anti-A or anti-B (79.5 %), anti-D (136%), anti-C (2,3%), and anti-Fya (2,3%). CONCLUSION: The eluate testing in cord blood samples is a valid, safe, and efficient test for the diagnosis of maternal erythrocyte alloantibodies.

Rhesus D alloimmunization in pregnancy from 1996 to 2015 in Iceland: a nation-wide population study prior to routine antenatal anti-D prophylaxis.

BACKGROUND: Rhesus D (RhD) incompatibility is still the most important cause of hemolytic disease of the fetus and newborn (HDFN) worldwide. The aim of this study was to investigate the incidence, causes, and consequences of anti-D alloimmunizations in pregnancy in Iceland, prior to implementation of targeted routine antenatal anti-D prophylaxis (RAADP) in 2018. STUDY DESIGN AND METHODS: This was a nation-wide cohort study of 130 pregnancies affected by RhD alloimmunization in Iceland in the period from 1996 through 2015. Data were collected from transfusion medicine databases, medical records, and the Icelandic Medical Birth Register. RESULTS: Of 130 RhD alloimmunizations, 80 cases (61.5%) represented new RhD immunization in the current pregnancy. Sensitization was discovered in the third trimester in 41 (51.3%) and occurred in the first pregnancy in 14 cases (17.5%). The most likely causative immunization event was the index pregnancy for 45 (56.25%), a previous pregnancy/birth for 26 (32.5%), abortion for 3 (3.75%), and unknown for 6 women (7.5%). Higher anti-D titers were associated with shorter gestational length, cesarean sections, positive direct antiglobulin test (DAT), and severe HDFN. Intrauterine transfusion (IUT) was performed in five pregnancies (3.8%), and 35 of 132 (26.5%) live-born neonates received treatment for HDFN; 32 received phototherapy (24.2%), 13 exchange transfusion (9.8%), and seven simple blood transfusion (5.3%). CONCLUSION: In about half of cases, RhD alloimmunization was caused by the index pregnancy and discovered in the third trimester. Thus, the newly implemented RAADP protocol should be effective in reducing the incidence of RhD immunization in Iceland in the future.

Red Blood Cell Antibodies in Hematology/Oncology Patients: Interpretation of Immunohematologic Tests and Clinical Significance of Detected Antibodies.

Red blood cell (RBC) transfusion is a cornerstone of the management of patients with hematology/oncology disorders. However, a potentially deleterious consequence of transfusion is the development of alloantibodies against blood group antigens present on RBCs. Such alloantibodies can be an obstacle in providing compatible units for transfusion. Providers in this arena must fully understand the testing performed by blood banks, as well as the consequences of detected antibodies. This article reviews immunohematologic tests, describes how autoimmune hemolytic anemia is classified by autoantibodies; outlines RBC alloimmunization rates, and presents strategies to prevent/mitigate the impact of RBC alloimmunization.

Autoimmune hemolytic anemia associated with renal urothelial cancer: A case report and literature review.

BACKGROUND: Autoimmune hemolytic anemia (AIHA) is hemolytic anemia characterized by autoantibodies directed against red blood cells. AIHA can be induced by hematological neoplasms such as malignant lymphoma, but is rarely observed in the urological field. We report a case of renal urothelial cancer inducing Coombs-positive warm AIHA and severe thrombocytopenia that was responsive to nephroureterectomy. CASE PRESENTATION: A 52-year-old man presented with a 1-month history of general weakness and dizziness. Hemoglobin level was 4.2 g/dL, and direct and indirect Coombs tests both yielded positive results. Abdominal computed tomography revealed huge left hydronephrosis due to a renal pelvic tumor measuring 4.0 x 4.0 x 3.0 cm, and renal regional lymph-node involvement was also observed and suspected as metastasis. Corticosteroid therapy was administered, and nephroureterectomy was performed. After surgical resection, the hemoglobin level gradually normalized, and direct and indirect Coombs tests yielded negative results. We thus diagnosed warm AIHA associated with renal urothelial cancer. CONCLUSION: To the best of our knowledge, this represents the first report of AIHA associated with renal urothelial cancer and severe thrombocytopenia responsive to nephroureterectomy. Renal urothelial cancer needs to be included in the differential diagnoses for warm AIHA, and nephroureterectomy represents a treatment option for AIHA.

The HI-STAR study: resource utilization and costs associated with serologic testing for antibody-positive patients at four United States medical centers.

BACKGROUND: Little is known about how the resource utilization and costs of serologic work ups for positive antibody screens vary across subpopulations based on diagnosis, transfusion history, and serologic testing history. STUDY DESIGN AND METHODS: Detailed data were collected on patient demographics, diagnoses, transfusion history, history of known allo- and autoantibodies, and specific serologic tests performed for 6077 consecutive serologic work ups in 3608 antibody-positive patients between 2009 and 2011 at four US academic medical centers. Direct testing costs were also determined at each site for each serologic test performed to calculate total costs per work up and per patient over the duration of the study. RESULTS: The mean direct cost of serologic testing was $114 per work up and $195 per patient. The mean cost per patient was significantly higher for 12 of 19 diagnostic categories evaluated, including autoimmune hemolytic anemia (mean cost per patient, $1490; p < 0.001), hematologic malignancies ($640, p < 0.001), and transplant recipients ($462, p = 0.019). Patient transfusion and serologic testing characteristics associated with greatest increases in costs included history of a warm autoantibody ($626, p < 0.001) and more than five prior transfusions ($404, p < 0.001). CONCLUSION: Antibody-positive patients with complex diagnoses or transfusion histories require significantly more resources and incur greater cost to assess red blood cell antibody status.

Relevance of blood groups in transfusion of sickle cell disease patients.

Blood groups are clinically significant in sickle cell disease (SCD) as transfusion remains a key treatment in this pathology. The occurrence of a delayed haemolytic transfusion reaction (DHTR) is not rare and is a life-threatening event. The main cause of DHTR is the production of alloantibodies against red blood cell antigens. The high rate of alloimmunization in SCD patients is mainly due to the differences of red blood groups between patients of African descent, and the frequently Caucasian donors. From an immuno-haematological point of view, DHTR in SCD patients has specific features: classical antibodies known to be haemolytic can be encountered, but otherwise non significant antibodies, autoantibodies and antibodies related to partial and rare blood groups are also frequently found in individuals of African descent. In some cases, there are no detectable antibodies. As alloimmunization remains the main cause of DHTR, it is extremely important to promote blood donation by individuals of African ancestry to make appropriate blood available.

Management of fetal hydrops due to maternal antibodies against a low incidence paternal red cell antigen: a novel insight from clinical practice.

A rare case of a low incidence red cell antigen causing severe fetal allo-immune red cell disease is presented. Discussion of how this can be diagnosed and successfully managed antenatally using middle cerebral artery Doppler ultrasound and maternal antibody titre levels for fetal surveillance and timing of intervention with intrauterine transfusion.

[Immune-mediated hemolytic anemia under oxaliplatin]. / Autoimmunhämolytische Anämie unter Oxaliplatin.

The induction of autoimmune hemolysis is a rare side effect of oxaliplatin. A 68-year-old patient was referred to our hospital because of progedient jaundice and exertional dyspnea. One day before she had received the 5th consecutive week of treatment of the 8th cycle of a chemotherapy according to FUFOX protocol with oxaliplatin and 5-fluorouracil because of metastasized adenocarcinoma of the sigma. Laboratory values revealed hemolytic anemia associated with thrombocytopenia and neutropenia. In the further clinical course a rapid decline of the hemoglobin (hb) level could be observed associated with a significant increase of hemolysis parameters. A direct Coombs test was positive consistent with oxaliplatin-mediated autoimmune anemia (AIHA) and a pulse therapy with steroids was started accompanied by transfusions resulting in a normalization of red blood cell and white blood cell counts. Chemotherapy was switched to an oxaliplatin-free regimen because of progressive tumor disease and induction of immune pancytopenia. Oxaliplatin-induced AIHA requires an immediate diagnosis since reexposition results in a more severe hemolysis. The direct Coomb's test represents the essential hallmark of the diagnosis.

Acute hemolysis of transfused A2 red cells by an auto-HI antibody.

BACKGROUND: Anti-HI is a common cold autoantibody that complicates serologic testing for underlying alloantibodies and has only rarely been associated with hemolysis. An unusual case of an acute hemolytic transfusion reaction (AHTR) due to an anti-HI autoantibody in a subgroup A1 patient transfused with A2 red blood cells (RBCs) is reported. CASE REPORT: A 56-year-old man presented to the hospital with anemia and gastrointestinal tract bleeding. His medical history was significant for congestive heart failure, obesity, and pulmonary hypertension. On admission, he was noted to have a hemoglobin level of 7.7 g per dL and therefore transfusion of RBCs was ordered. The patient was group A, D- with a reactive antibody screen due to a cold autoantibody with HI specificity. Further serologic investigation did not detect any alloantibodies. The patient was issued an electronically cross-matched group A, D- unit of RBCs. Several hours after the transfusion, he was found to be producing "Coca-cola"-colored urine with gross hemoglobinemia visible in a posttransfusion specimen, indicating an AHTR. A transfusion reaction investigation excluded mistransfusion or a missed alloantibody and instead revealed that the patient's anti-HI had a high thermal amplitude and that the implicated unit of RBCs was from the A2 subgroup. The patient subsequently tolerated transfusion of a unit of group A1 RBCs through a blood warmer without any signs or symptoms of hemolysis. CONCLUSION: This case illustrates that anti-HI autoantibodies rarely may behave like alloantibodies and cause AHTRs. Subsequent RBC transfusion with an appropriate ABO group or subgroup through a blood warmer is well tolerated.

Cutting edge: allogeneic CD4+CD25+Foxp3+ T regulatory cells suppress autoimmunity while establishing transplantation tolerance.

An important unresolved question with regard to T regulatory (Treg) cell specificity and suppressive activity is whether allogeneic Treg cells inhibit self-reactive T cells. In the present study, this issue was addressed using IL-2Rbeta-deficient mice that develop rapid lethal autoimmunity due to impaired production of Treg cells. We show that adoptive transfer of completely MHC-mismatched Treg cells into IL-2Rbeta(-/-) mice resulted in life-long engraftment of the donor cells, which exhibited skewed reactivity toward host alloantigens, and prevented autoimmunity. Thus, Treg cells that underwent thymic selection by peptide/MHC class II complexes distinct from those recognized by autoreactive T cells, still effectively suppress autoimmunity. Remarkably, when such animals were skin grafted, they exhibited dominant tolerance to those grafts bearing MHC molecules that were shared with donor Treg cells. Collectively, these data demonstrate that effective engraftment by allogeneic Treg cells controls autoimmunity and results in permissive conditions for long-term acceptance of allografts.

Review: complement receptor 1 therapeutics for prevention of immune hemolysis.

The complement system plays a crucial role in fighting infections and is an important link between the innate and adaptive immune responses. However, inappropriate complement activation can cause tissue damage, and it underlies the pathology of many diseases. In the transfusion medicine setting, complement sensitization of RBCs can lead to both intravascular and extravascular destruction. Moreover, complement deficiencies are associated with autoimmune disorders, including autoimmune hemolytic anemia (AIHA). Complement receptor 1 (CR1) is a large single-pass glycoprotein that is expressed on a variety of cell types in blood, including RBCs and immune cells. Among its multiple functions is its ability to inhibit complement activation. Furthermore, gene knockout studies in mice implicate a role for CR1 (along with the alternatively spliced gene product CR2) in prevention of autoimmunity. This review discusses the possibility that the CR1 protein may be manipulated to prevent and treat AIHA. In addition, it will be shown in an in vivo mouse model of transfusion reaction that recombinant soluble forms of CR1 can reduce complement-mediated RBC destruction, thereby prolonging survival of transfused RBCs. It is proposed that CR1-based therapeutics have potential for effective and safe prophylactic short-term use and for treatment of hemolytic transfusion reactions.

A novel human CD32 mAb blocks experimental immune haemolytic anaemia in FcgammaRIIA transgenic mice.

A fully human IgG1 kappa antibody (MDE-8) was generated, which recognised Fc-gamma receptor IIa (FcgammaRIIa) molecules on CD32 transfectants, peripheral blood monocytes, polymorphonuclear cells and platelets. This antibody blocked FcgammaRIIa ligand-binding via its F(ab')(2) fragment. Overnight incubation of monocytes with F(ab')(2) fragments of MDE-8 leads to a c. 60% decrease in cell surface expression of FcgammaRIIa. MDE-8 whole antibody induced a concomitant c. 30% decrease of FcgammaRI on THP-1 cells and monocytes. In humans FcgammaRIIa plays an important role in the clearance of antibody-coated red blood cells in vivo. As an equivalent of FcgammaRIIa does not exist in mice, the in vivo effect of MDE-8 was studied in an FcgammaRIIa transgenic mouse model. In these mice, antibody-induced anaemia could readily be blocked by MDE-8. These data document a new human antibody that effectively blocks FcgammaRIIa, induces modulation of both FcgammaRIIa and FcgammaRI from phagocytic cells, and ameliorates antibody-induced anaemia in vivo.

CD4+CD25+ regulatory T cells control induction of autoimmune hemolytic anemia.

Autoimmune hemolytic anemia (AIHA) is the result of increased destruction of red blood cells (RBCs) due to the production of autoantibodies, and it can be life-threatening. To study the mechanisms that trigger AIHA, we used the Marshall-Clarke and Playfair model of murine AIHA, in which mice repeatedly immunized with rat RBCs develop erythrocyte autoantibodies as well as rat-specific alloantibodies. We analyzed the role of CD25(+) T-regulatory subsets in controlling AIHA in C57/Bl6 mice using antibody depletion studies. Treatment with anti-CD25 antibody but not isotype control prior to immunization with rat RBCs increased the incidence of AIHA from 30% to 90%. Adoptive transfer of purified splenic population of CD4(+)CD25(+) but not CD4(+)CD25(-) cells from immunized mice into naive recipients prevented the induction of autoantibody production. Altogether, our data establish a critical role for CD4(+)CD25(+) cells for control of AIHA, which may help to establish therapeutic strategies for treatment of AIHA.

Transgenic expression of CTLA-4 controls lymphoproliferation in IL-2-deficient mice.

IL-2-deficient mice develop a lymphoproliferative and autoimmune disease characterized by autoimmune hemolytic anemia (AHA) and inflammatory bowel disease. We have previously reported that IL-2 is necessary for optimal up-regulation of CTLA-4, an inducible negative regulator of T cell activation. In this study, we have tested the hypothesis that reduced expression of CTLA-4 in IL-2-deficient T cells contributes to the pathogenesis of disease in IL-2-deficient mice. Expression of CTLA-4 as a transgene completely prevented lymphoaccumulation and AHA in IL-2-deficient mice. The normalization of T cell numbers was due to inhibition of expansion of conventional CD4+CD25- T cells rather than to rescue of the numbers or function of CD4+CD25+ regulatory T cells, suggesting that CTLA-4 expression on conventional T cells plays a role in maintaining normal T cell homeostasis. In addition, the inhibitory effect of the CTLA-4 transgene on T cell expansion was at least in part independent of CD28 expression. Our results suggest that deficient CTLA-4 expression on conventional T cells contributes to the pathophysiology of the lymphoproliferative disease and AHA in IL-2-deficient mice. Thus, restoring CTLA-4 expression in T cells may be an attractive strategy to control clinical autoimmune diseases in which CTLA-4 expression is reduced.

Beneficial effect of a human monoclonal IgM cryoglobulin on the autoimmune disease of New Zealand black mice.

NZB mice spontaneously develop an autoimmune disease characterized by autoimmune hemolytic anemia, thymic atrophy, lymphoid hyperplasia, and hypergammaglobulinemia. The aim of this study was to examine the hypothesis that cryoglobulins may have an immunoregulatory effect on the autoimmune process. The effect of human monoclonal IgM cryoglobulin preparations (including Cryo13, Cryo14, and Cryo16) isolated from the serum of patients with Waldenström's macroglobulinemia on the autoimmune disease of NZB mice was therefore studied. The effect of cryoglobulin preparations was evaluated on several disease parameters, i.e., survival, severity of anemia, and serum IgM and IgG levels (hypergammaglobulinemia). We found that immunization of NZB mice with Cryo13 at 3 months of age delayed the course of the disease, whereas Cryo14 and Cryo16 were ineffective. Furthermore, the effect of Cryo13 was long lasting. On the other hand, Cryo13 was able to react with 8 of 32 mouse monoclonal natural IgM autoantibodies. In contrast, Cryo14 was able to bind only 2 and Cryo16 none of these mouse monoclonal IgM antibodies. These results indicate that, in this model of autoimmune pathology, the beneficial effect of Cryo13 is mediated by its idiotypic interaction with the murine natural autoantibody network.

Autoimmune hemolytic anemia in patients with SCID after T cell-depleted BM and PBSC transplantation.

We report a high incidence (19.5%) of autoimmune hemolytic anemia (AIHA) in 41 patients with SCID who underwent a T cell-depleted haploidentical transplant. Other than infections, AIHA was the most common post-transplant complication in this patient cohort. Clinical characteristics and treatment of eight patients who developed AIHA at a median of 8 months after the first T cell-depleted transplant are presented. All patients had warm-reacting autoantibodies, and two of eight had concurrent cold and warm autoantibodies. Clinical course was most severe in two patients who had cold and warm autoantibodies. Five patients received specific therapy for AIHA. Successful taper off immunosuppressive therapy for AIHA coincided with T cell reconstitution. Delayed reconstitution of T cell immunity, due to T cell depletion, immunosuppressive conditioning and CsA, as well as paucity of regulatory T cells, are the likely explanations for the occurrence of AIHA in our patient cohort. Screening of the population at risk may prevent morbidity and mortality from AIHA.

Interleukin-2 is indispensable for development of immunological self-tolerance.

Interleukin-2-deficient mice (IL-2(-/-)) manifest severe immune system abnormalities characterized by an uncontrolled activation and proliferation of lymphocytes. A systemic autoimmune syndrome results, and hemolytic anemia leads to early death especially in mice derived from a BALB/c genotype. Remarkably, IL-2 treatment prevents both the activation of the immune system and the development of autoimmune disease. Moreover, adoptive transfer of lymphocytes from IL-2-treated IL-2(-/-) animals confers protection to IL-2(-/-) mice, suggesting that IL-2 induces a postnatal differentiation/maturation of regulatory cells necessary for self- and non-self-discrimination.