Positive Indirect Antiglobulin Test Research Articles

Significance of red cell alloantibodies other than anti-D during pregnancy and their effect on the newborn: A case series

Contrary to well-established guidelines in developed countries, awareness regarding red cell alloantibodies in antenatal period are lacking in India. Investigating for indirect antiglobulin test (IAT) is mostly limited to the Rh D negative antenatal cases. This case series revisits this vital aspect of maternal and fetal safety. Instances of alloantibody other than anti-D are reported.Study was done in Transfusion Medicine department of a tertiary care hospital in North India during 2019-2020. IAT was performed not during the 1st or 2nd trimesters of pregnancy but as a routine compatibility test during delivery. Patients with positive IAT were further evaluated for the detection of alloantibody by using identification panel red cells. Result: Eight antenatal cases with irregular antibodies other than anti-D during 2019-2020 are described. Antibodies detected per patient were single (three cases of anti-E, one of anti-Fya, one of anti-M) or multiple (two cases of anti-E plus anti-c, one of anti-E plus anti-K). Direct antiglobulin test of four babies born to these mothers was found to be positive, one of whom was still born and rest recovered with medical management. Two other babies had DAT negative and two mothers presented late after still birth. Alloantibody titer indicated in patient with anti-E during mid-pregnancy had titer was undetectable by standard tube technique.Non anti-D alloantibodies can potentially affect fetus, asserting equal attention as anti-D. IAT should not be missed in pregnancy as it is common to investigations for compatibility as well as for fetal wellbeing assessment.

The Indirect Antiglobulin (Coombs') Test Is Specific but Less Sensitive Than the Direct Antiglobulin Test for Detecting Anti-Erythrocytic Autoantibodies and Thereby Immune-Mediated Hemolytic Anemia in Dogs.

The immunodiagnostic assessment of dogs suspected of having immune-mediated hemolytic anemia (IMHA) is based on persistent autoagglutination of erythrocytes (after three saline washes), marked spherocytosis, and a positive direct antiglobulin (Coombs') test (DAT). However, the value of using the indirect antiglobulin test (IAT) for the detection of anti-erythrocytic autoantibodies in serum from dogs suspected of having IMHA is unclear. To evaluate the IAT, leftover serum samples from a large cohort of 94 dogs suspected of having IMHA and for which DAT results were known were incubated with DAT- erythrocytes, and five IAT techniques were performed (in part with different reagents and temperatures): microtiter plate (MICRO), microcapillary, laboratory gel column, gel minitube kit (GEL KIT), and immunochromatographic strip kit. Two IAT techniques (MICRO at 37 °C and GEL KIT with rabbit anti-dog polyvalent reagent) detected autoantibodies against erythrocytes in serum from 53% and 57% of DAT+ dogs, respectively, while other IATs performed less well. Moreover, while the analytic specificity of the IAT methods compared to the DAT ranged from 96-100%, the sensitivity range was only 9-57%. Thus, we still recommend DAT for diagnosis and monitoring of IMHA in dogs but conclude that a positive IAT result may aid diagnostically when serum is available, but fresh red blood cells are not.

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

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. 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. 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). 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.

Diagnosis of severe anaemia and positive antibody screening as consequences of pre-analytical error.

The pre-analytical phase is the principal source of errors in laboratory medicine and continues to pose a challenge to laboratory professionals. We present the case of a 73-yearold female patient with a very low hemoglobin level (69 g/L) and positive indirect antiglobulin test result that indicates the key role of phlebotomy as an important error-prone process in which mistakes can have serious consequences for the patient's diagnosis and treatment. We conclude that there is still an urgent and continuous need to provide educational activities for healthcare professionals involved in blood collection, improve blood collection guideline adherence, and eliminate the errors which can affect diagnosis and treatment, thus jeopardising patient safety.

Alloimmunization and Autoimmunization in Multi-Transfused Thalassemic Patients: A Single Center Study

Aim: To determine frequency of alloimmunization and autoimmunization among the patient of thalassemia with history of multiple blood transfusions. Methods: This study was conducted by consecutive sampling in six months duration from September 2020 to August 2021 at the department of Hematology and blood Transfusion Medicine, of University of Child Health Sciences, The Children's Hospital Lahore. Any patient with a positive Direct antiglobulin test (DAT) was labeled as auto-immunized and a positive indirect antiglobulin test (IAT) was labeled as alloimmunized. Results: Total 90 cases were enrolled with 62% male and 38% females with a mean age 6.04 + 3.3 years (range of age: 7 months to 14 years). Antibody screening and auto-antibodies were positive in 4.4% (n= 4) cases each, and allo-antibodies in 6.7% (n=6) cases (anti-E in 2, anti-C in 2, anti-K and anti-e in 1 each). Among all these patients of beta thalassemia, spleen was enlarged in 71% cases; around half of these were &lt;5 years old. Around 96% had first transfusion &lt;2 years. The frequency of patients positive on DAT, IAT and on anti-body screening was significantly related to the frequency of blood transfusion Practical Implications: Autoantibodies produce a positive direct antiglobulin test (DAT), resulting in hyperhemolysis of red cells in thalassemic patients, which exacerbates the existing alloantibodies factor in children who have received several blood transfusions. The gap between transfusions will be shortened. Routinely, greater emphasis is placed on the identification of allo-antibodies, but auto-antibodies should also be evaluated so that this phenomena may be better understood and handled. This study was conducted to examine the link between a greater transfusion demand and the existence of auto or allo antibodies in Thalassemia patients. I Conclusion: We found Alloimmunization and autoimmunization together not very uncommon in transfusion dependent patients of Thalassemia. The frequency of transfusions is affected in co-existing states. Extended matching, as well as early diagnosis and control of Auto and allo-antibodies both can improve the efficacy of blood transfusion. Keywords: Autoantibodies, IAT, DAT, Coomb’s test, Thalassemia, Allo-immunization

Enfermedad hemolítica por incompatibilidad de factor RH D variante tratado con inmunoglobulina humana

Hemolytic disease of the newborn may be due to Rh disease, ABO blood group incompatibility, and alloantibody reactions. His management plan includes: enteral or intravenous hydration, phototherapy, exchange transfusion, and intravenous immunoglobulin. The American Academy of Pediatrics recommends IV Ig for newborns with hemolytic disease due to Rh incompatibility, ABO and increased bilirubin, as it may be an alternative to exchange transfusion and has been reported in some clinical trials. We present the case of a newborn group O Rh D-Variant, with predominantly indirect hyperbilirubinemia plus hemolytic anemia; who was managed with phototherapy, exchange transfusion, IV Ig and packed red blood cell transfusion with favorable evolution. The diagnosis of hemolytic disease of the newborn due to Rh incompatibility of subgroups is confirmed by demonstrating antibody-mediated hemolysis either by a positive direct or indirect antiglobulin test (DAT), so it should be considered in newborns with pathological jaundice who do not have respond to conventional treatment, presenting a risk of severe hyperbilirubinemia and hemolytic anemia.

To Reflex or Not to Reflex: A Time and Cost-Effectiveness Analysis of Autocontrol with Reflex DAT versus Direct DAT.

Performing autocontrol with a reflex direct antiglobulin test (DAT) or directly performing IgG DAT only for alloantibody detection has been a matter of institutional preference. The aim of this study is to evaluate antibody identification (ABID), local cost, and staff time savings of both processes. We retrospectively reviewed all positive indirect antiglobulin tests with corresponding ABID, DAT, autocontrol, and patients with newly identified antibodies in 2014 and 2016. The number of tests performed, ABID, and the cost differences between methods were compared. Cost analysis was estimated from direct material costs, labor costs, and time spent per ABID workup. Annual costs and time saved by performing direct IgG DAT only were $8460 and 180 hours, respectively. The percentage of new ABID in 2014 and 2016 was identical (3.3%). Removing autocontrol with reflex DATs at our center reduced costs and staff time while maintaining a comparable rate of positivity of ABID.

Low prevalence red blood cell antigens: transfusions, babies, and changing demographics

See article on page 870–874, in this issue

A rare case of immune hydrops in an “Elevated D” pregnancy

The D-/-phenotype is a rare variant of the Rh system, in which red blood cells express only D antigen. Sensitized D-/-women carry a risk of hemolytic disease of fetus and newborn (HDFN) and pose a challenge in management due to nonavailability of antigen negative blood for intra-uterine/exchange-transfusion. A 23y old G2P1L1A0, blood group “A” Rh D+C-c-E-e- presented at 20 weeks' period of gestation (POG) with a positive indirect antiglobulin test. Cordocentesis at 23 weeks' POG revealed fetal's blood group as “B” Rh D+, Direct Coombs Test 4+, Hemoglobin 2.8 g/dL. USG with MCA-PSV indicated rapid development of fetal anemia and hydrops. Patient's sibling had D-/-phenotype, but was ABO-incompatible with the fetus. Rapidity of progression of case resulted in intrauterine fetal demise at 27 weeks' POG. HDFN, in rare blood groups, leads to problems in arranging compatible units in developing countries due to lack of centralized rare donor registries.

Routine indirect antiglobulin testing of blood donors—a further step toward blood safety: an experience from a tertiary care center in northern India

This scientific article emphasizes the importance of a policy for antibody screening of all blood donors as a step to further improve blood safety. We also report the incidence of red blood cell (RBC) alloimmunization in healthy blood donors obtained using a cross-sectional prospective study from September 2017 to January 2019 in the Department of Transfusion Medicine of a tertiary care referral and teaching institute in northern India. The indirect antiglobulin test (IAT) for unexpected RBC antibodies was performed by the conventional tube test with pooled group O RBCs on all donor units irrespective of their D status. Samples with positive IATs were sent to the Immune Hematology Reference Laboratory for further immunohematolo-gy workup, maintaining predefined optimal storage and transport conditions. Of the 10,390 donors studied, 9959 were males and 431 were females. The incidence of unexpected antibodies (antibodies other than those of the ABO blood system) among the blood donors was found to be 0.18 percent (19 of 10,390 with 25 alloantibodies). Of the 19 alloimmunized donors, 16 (84.2%) were male (alloimmunization rate 0.16%, 16 of 9959) and 3 (15.8%) were female (alloimmunization rate 0.69%, 3 of 431) (p = 0.01; chi-square test). In our study, the most frequent alloantibodies identified were of the Lewis blood group system (17 of 25 [68%] in 14 of the 19 alloimmunized donors). The second most common allo-antibodies belonged to the Rh blood group system (4 of 25 [16%] in 3 of the 19 alloimmunized donors), followed by those of the MNS blood group system (3 of 25 [12%] in 2 of 19 alloimmunized donors). Anti-K was found in one donor (1 of 25 [4%]). Based on the results of the study, we recommend that a policy of routinely performing IATs on all donor units, irrespective of their D status, be adopted as an essential component of safe blood transfusion practices.

PB2141 FEATURES OF THE DIRECT ANTIGLOBULIN TEST IN PATIENTS WITH MULTIPLE MYELOMA

Background:The direct antiglobulin test (DAT) is used to detect autoantibodies that are fixed on the surface of red blood cells. A differentiated DAT allows to estimate the amount of absorbed immunoglobulins, describe their class and subclass, and detect the components of the complement on the membrane of red blood cells. This information helps to predict the risk of hemolysis and suggest the cause of anemia in a particular patient.Aims:To study the frequency and features of positive DAT in patients with multiple myeloma (MM).MethodsThe results of differentiated DAT were analyzed in 80 patients first hospitalized at the Institute clinic in 2018–2019 with the diagnosis MM. DAT was performed by gel method using anti‐IgG/C3d, DC‐Screening I and DAT IgG1/IgG3 cards (BioRad, USA). The frequency of positive DAT in patients was compared with the same in 200 healthy residents of the region–donors of blood components.Results:All blood donors were DAT‐negative. Autoantibodies to red blood cells were detected in 27.5% (22) of patients with MM (p &lt; 0.05).The intensity of the reaction (+) was observed in 50.0% (11) of patients with positive DAT, (++)–in 50.0% (11). DAT (++ + ), (++ + +) was not revealed. In the 100% of cases immunoglobulins G subclasses 2,4 were fixed on the surface of red blood cells, associated with a low risk of immune hemolysis. None of the patients was positive due to immunoglobulins classes A, M and complement components, which could contribute to the development of hemolytic complications. No clinical and laboratory signs of hemolysis were observed in the patients with positive DAT.Positive DAT was more frequently found in the group of patients with MM older than 60 years (48.0%), whereas in the group of patients younger than 60 years it was 18.2% (p &lt;0.05).When observing patients with MM with positive DAT, it was noted that in one third of patients receiving chemotherapy, the result of DAT becomes negative within 5 months.Autoantibodies can interact with test and donors red blood cells, being detected in an indirect antiglobulin test (IAT). Positive IAT was in 9.1% of patients with positive DAT and in 3.4% ‐ with negative. These patients had difficulties in donor's selection due to non‐specific agglutination.Summary/Conclusion:Even though positive DAT is often found in patients with MM, not in every case it should be regarded as a sign of autoimmune hemolysis. To correctly assess the risk of hemolysis, physicians should analyze other laboratory and clinical data. Positive DAT may be correlated with the difficulties of selection of the donor for such patient.

Relapsing Evans syndrome and systemic lupus erythematosus with antiphospholipid syndrome treated with Bortezomib in combination with plasma exchange

Relapsing Evans syndrome (ES) and systemic lupus erythematosus (SLE) with secondary antiphospholipid syndrome (APS) is very rare association. Coexistence of these syndromes is potentially fatal and require high-dose combined immunosuppressive therapy. We describe a case of successful use of Bortezomib and plasma exchange in a patient with ES and APS refractory to standard therapy. Thirty-two-year-old male who presented episodes of relapsing hemolytic anemia, pancytopenia and multiple thrombosis with positive direct and indirect antiglobulin test result, lupus anticoagulant and medium titer of anti-beta-2-glycoprotein 1 and anti-cardiolipin antibodies was diagnosed with ES and SLE with secondary APS. High-dose therapy by steroids and Cyclosporin A were started with temporary improvement. There was also no stable improvement with Rituximab and Cyclophosphamide. Bortezomib in combination with cyclosporine A and plasma exchange was introduced. He had stable improvement in hematological parameters with no evidence of relapse of hemolytic crisis or thrombosis during a follow-up for 1 year.

Red blood cell alloimmunization among hospitalized patients: transfusion reactions and low alloantibody identification rate

BackgroundUnexpected red blood cell alloantibodies can cause hemolytic transfusion reactions. In this study, the prevalence of alloimmunization, the rate of identification of alloantibodies and the rate of blood transfusion reactions among transfused patients were identified in a clinical emergency hospital in Brazil. MethodsTransfusions and clinical records of patients who had a positive indirect antiglobulin test between January and December 2013 were analyzed. ResultsOf 1169 patients who received blood transfusions, 28 had positive indirect antiglobulin tests, with one patient having two positive tests at different times, resulting in 29 positive tests during the period of this study. Alloantibodies were identified in 58.6% (17/29) of the cases. In 27.5% (8/29), identification was inconclusive and it was not possible to confirm alloimmunization. The rate of red blood cell alloimmunization was 1.71% (21/1169). Of 21 cases of alloimmunization, four (19%) were unidentified due to an unusual agglutination profile. All identified alloantibodies were clinically significant (10/17 anti-Rh, 5/17 anti-Kell and 2/17 anti-MNS). In two patients who had positive indirect antiglobulin tests, one had an unidentified alloantibody, and the other had an inconclusive test and developed a hemolytic transfusion reaction. ConclusionThe prevalence of clinically important red blood cell alloantibodies and hemolytic transfusion reactions among patients with unidentified alloantibodies suggests that specific laboratory techniques should be performed to identify alloantibodies in cases of pan-reactivity or autoantibodies to improve transfusion safety.

False-negative compatible antiglobulin crossmatches in samples with alloantibodies to cognate red blood cell antigens.

Patient samples showing a positive indirect antiglobulin test are further tested to identify alloantibody specificity using a panel of phenotypically characterized group O reagent red blood cells (RBCs). Donor RBCs phenotypically negative for the antibody specificity are then serologically crossmatched using an antiglobulin reagent. This latter test is performed to identify any incompatibility due to the presence of undetected minor blood group antibodies and considered an important step in patient safety. Samples with well-characterized alloantibodies were intentionally crossmatched against donor RBCs expressing the cognate antigen. In a separate set of specimens, the alloantibody was titered and crossmatched against both heterozygous and homozygous cells. Thirty-five samples containing 10 common alloantibodies crossmatched against 240 ABO-compatible donor cells phenotypically positive for the cognate antigen showed compatible crossmatches in 89 of 240 (37%). Antibody titering of 12 alloantibodies showed that a titer of 2 or more was required for incompatibility of all homozygous cells and a titer of 8 or more for incompatibility of all heterozygous cells. The antiglobulin crossmatch has a high failure rate (false-negatives) related to antibody titer and donor cell zygosity and is not reliable in interdicting incompatibility due to minor blood group antibodies.

Investigation of the Etiology of Anemia in Thromboangiitis Obliterans.

During a review of patients admitted with thromboangiitis obliterans (TAO), there was evidence of normochromic normocytic anemia and abrupt changes in hemoglobin (Hgb) levels in patients with several hospital admissions. Therefore, the evidence of hemolytic anemia was evaluated based on 37 banked plasma samples taken from Caucasian male TAO patients during disease exacerbation between 2012 and 2014. The patients' hospital records, including clinical manifestations and complete blood count, were evaluated. The following tests were performed on all samples: indirect antiglobulin test (IAT), C-reactive protein (CRP), high-sensitivity CRP (hsCRP), lactate dehydrogenase (LDH), haptoglobin, indirect bilirubin, d-aspartate aminotransferase (AST), and d-alanine aminotransferase (ALT). The mean age of the patients was 40 ± 7 years. Two patients underwent below-knee amputation. The mean hospital-documented Hgb of the patients was 12.9 ± 2.6 g/dL. CRP and IAT were positive in 75.6 and 70.2% of the samples, respectively. The tests and corresponding results were as follows: hsCRP, 14.07 ± 2.37 µg/mL; LDH, 2,552 ± 315 u/L; haptoglobin, 2.27 ± 1.1 g/L; indirect bilirubin, 0.09 ± 0.04 mg/dL; AST, 67 ± 7 u/L; and ALT, 26 ± 3 u/L. There was a significant inverse correlation between hsCRP and hospital-documented Hgb level (p = 0.03). Anemia with the positive IAT in most of the samples, high LDH and AST, and normal ALT are suggestive of hemolytic anemia. Normal indirect bilirubin is consistent with intravascular hemolysis. The positive CRP and elevated haptoglobin levels could be due to systemic inflammation in TAO. However, it is not known if an autoantigen or an infectious antigen is responsible for TAO systemic inflammation and induction hemolytic anemia. As such, the underlying mechanism of anemia in TAO could be part of the footprint of its main etiology.

Direct Antiglobulin Test Positivity in Children With Acute Lymphoblastic Leukemia at Diagnosis

Direct antiglobulin test positivity had been reported in the course of some lymphoproliferative neoplasms. However, there are a few case reports describing direct antiglobulin test (DAT) positivity in children with acute lymphoblastic leukemia (ALL). We herein report 8 patients who had positive DAT among 95 newly diagnosed children with ALL. None of these patients had evidence of hemolysis during the follow-up. An antibody was detected in 2 of 8 patients with positive DAT. These 2 children also had positive indirect antiglobulin test (IAT); an autoantibody that was reactive at 4°C, and an alloantibody (anti E) that was reactive at 37°C was detected. We believe DAT positivity in ALL without significant hemolysis is not a rare disorder, and a need for further prospective studies is apparent.

Cancer of the sigmoid colon and antibodies. A puzzle

In this work we describe the case report of a woman affected by cancer of the sigmoid colon and with a positive direct antiglobulin test (DAT) and indirect antiglobulin test (IAT). Case report with results: A meticulous medical history showed that the woman had been suffering from recurrent fetal loss. Then she had cardiac and coagulative problems. These data suggested a phospholipid syndrome. Conclusion: The patient had a medical history positive for a phospholipid syndrome and we think that this disease could explain the onset of the autoantibody.

Red Blood Cell Alloimmunization and Hemolytic Disease of the Fetus and Newborn: New Approaches Using Animal Models

Women may become alloimmunized to foreign red blood cell (RBC) antigens after exposure during transfusion or pregnancy/delivery. These alloantibodies can be detrimental to developing fetuses/neonates, with six in every 1000 pregnancies being affected by maternal alloantibodies. Despite being described more than 80 years ago, hemolytic disease of the fetus and newborn (HDFN) has few preventive or therapeutic options. Outside of antigen avoidance, the most effective maternal preventive therapy to date is Rh immune globulin. However, it targets just one of the more than 50 antigens implicated in HDFN, and its mechanism of action remains unknown. Furthermore, treatment options for affected fetuses are limited largely to intrauterine transfusions of antigen negative RBCs. With a decrease in HDFN cases due to Rh(D), KEL has emerged as one of the most widely implicated antigens. We now describe a transgenic murine model in which the human KEL antigen is expressed on murine RBCs, with clinical significance in both pregnancy and transfusion settings. Transgenic animals were generated with expression of the human KEL2 antigen (referred to herein as KEL) on their RBCs using a β-globin promoter. KEL expression was evaluated on fetal liver and bone marrow erythroid precursors, mature RBCs, and organs. C57BL/6 or MuMT females were bred with transgenic heterozygous KEL males. Maternal serum was collected during pregnancy and after delivery, with anti-KEL glycoprotein responses measured by flow cytometric crossmatch. Newborn pups were evaluated for KEL positivity, degree of anemia, and presence of maternal anti-KEL. Additionally, the effect of anti-KEL alloantibodies on fetal RBC precursors was evaluated at multiple stages of gestation. Lastly, females alloimmunized through pregnancy were transfused with incompatible KEL RBCs labeled with a lipophilic dye, and females alloimmunized through transfusion were bred with KEL males. Transgenic mice have RBC specific expression of the KEL glycoprotein, with antigen detected on early and late RBC precursors in the fetal liver and bone marrow but not on any tested organ. Fetal/maternal blood exchange was maximally detected after delivery, with the majority of mothers developing anti-KEL glycoprotein antibodies (IgM and all IgG subclasses) within weeks of delivery. All IgG subclasses of anti-KEL crossed the placenta and bound to RBC precursors and mature RBCs in developing KEL positive pups; KEL negative pups had positive indirect antiglobulin tests. Maternal anti-KEL glycoprotein titers increased with antigen exposure, with fewer KEL positive pups born during successive pregnancies to alloimmunized C57BL/6 but not MuMT females. Affected KEL positive pups were anemic, and some were stillborn and hydropic-appearing. As has been described in humans, maternal anti-KEL alloantibodies suppressed the development of fetal KEL RBC precursors at all levels of maturation. Additionally, newborn pups had a relative reticulocytopenia, with reticulocyte recovery within a week after birth. Multiparous alloimmunized females exhibited rapid clearance of transfused incompatible KEL RBCs, and females alloimmunized through KEL RBC transfusion also had pups affected by HDFN. To the best of our knowledge, this is the first animal model of HDFN in which pregnancy stimulates alloantibodies to a paternally derived RBC antigen, with these alloantibodies being clinically significant in both pregnancy and transfusion settings. The anti-KEL glycoprotein alloantibodies generated in this model have similar effects on murine RBCs as anti-KEL1 alloantibodies have on human RBCs. Such effects include suppression of erythropoiesis, fetal anemia, and even hydrops fetalis. This model thus provides a platform to study not only the induction, placental transfer, and consequences of maternal RBC alloantibodies, but also to investigate potential preventive therapies (including “KEL” immune globulin). Long-term translational goals of this work include minimizing the dangers of RBC alloantibodies to developing fetuses and neonates, through the development of targeted maternal immunomodulatory therapies. Disclosures:No relevant conflicts of interest to declare.

Autoimmune Hemolytic Anemia In Cancer Patients At a Tertiary Center In Southern Nigeria

Background With the emergence of non-communicable diseases accounting for 63% of deaths globally in 2008, and about four-fifths of these deaths occurring in the low and middle income countries; Cancer has been identified as the second leading cause of death by the World Health Organization. Anemia is one of the commonest symptoms of cancer and very frequently causes the patient to seek for medical attention even before the cancer is diagnosed. Anemia contributes tremendously to the co-morbidity of cancer, and proper treatment of anemia improves quality of life. Autoimmune haemolytic anemia (AIHA) is a heterogeneous group of diseases characterized by autoantibody production against red cell antigens, leading to their shortened survival. Autoimmunity and cancer are conditions associated with impaired cellular regulation. Immune dysregulation is believed to play a pathogenic role in the development of both autoimmunity and neoplasia. The objectives of this study are to provide baseline data on the prevalence of anemia in cancer in the Niger-Delta region of Nigeria, to determine if AIHA plays a significant role in anemia of cancer, and ascertain the cancers in which AIHA occurs in our environment. Methods This was a case-control study conducted on patients with confirmed diagnoses of solid, soft-tissue and haematological malignancies. Controls were healthy age, sex matched subjects. Cases with, and without exposure to chemotherapy were analyzed as sub groups. Three hundred and seventy six (376) participants (188 cancer patients and 188 controls) were enrolled into the study. Complete blood count, reticulocyte count, peripheral blood film, direct antiglobulin test (DAT), indirect antiglobulin test (IAT) and bilirubin assays were done. The DAT was performed on fresh samples not more than 6 hours after collection using polyspecific antihuman globulin. Analysis was done using Microsoft Office Excel 2007® Results Anemia was found in 124 (66%) of the total cancer population, while only 5 (2.7%) participants had anemia in the control group. Anemia was found in 98 of 149 (65.8%) in the cancer group not yet exposed to chemotherapy, while 26 of 39 cases (66.7%) in the cancer group who had received chemotherapy had anemia. Three (1.6%) of the 188 cancer patients (all not exposed to chemotherapy) were found to have a positive DAT, of which two were strongly positive with features of hemolysis and therefore had AIHA. The 2 patients with AIHA had chronic lymphocytic leukaemia. The third case of positive DAT had malignant teratoma and a weak DAT with no features of hemolysis. The 3 cases of positive DAT had positive IAT. AIHA was the aetiology of the anemia in 2 (2%) of the 98 cases with anemia in the group not yet exposed to chemotherapy. The group receiving chemotherapy had no positive DAT. There was no positive DAT in the control group, however there is no significant difference in the occurrence of AIHA in the cancer group from the controls (p= 0.08) Conclusion The data generated shows that anemia is common in patients with cancer as generally reported. The prevalence of anemia in the cancer group not yet exposed to chemotherapy and those on chemotherapy was about the same. Our data also suggests AIHA may play a role in the aetiology of anemia of cancer; however, patients with lymphoid malignancies are more predisposed. Our results show that a positive DAT may occur without hemolysis. Disclosures: No relevant conflicts of interest to declare.

Identifying D-positive donors using a second automated testing platform

Abstract Because of the variability of D expression, one method may be inadequate to correctly classify donors with variant RHDalleles. We evaluated the use of a solid-phase automated platform (ImmucorGamma Galileo) to confirm D– test results obtained on first-time donors on the Beckman Coulter PK7300 automated microplate test system. Samples with discordant results were analyzed by serologic tube methods, RHD genotyping using the BLOODchip platform (Progenika), and, if necessary, sequencing. We estimated the number of cases of alloimmunization in women younger than 50 years likely to be prevented by the addition of Galileo testing. From May 2011 to May 2012, 910,220 donor samples were tested; 15,441 were first-time donors with concordant D– results. Five donors tested D– on the PK7300 and weak D+ on the Galileo; one was found to be a false positive on further testing. On manual testing, the other four donors had positive indirect antiglobulin test results with one to three of the antisera used and were C+. On BLOODchip testing, two donors were classified as D+, and two were assigned a “no call.” D variants included weak D type 67, weak D type 9, and two novel variants. Approximately 10 percent of D– units are transfused to women younger than 50 years. Assuming an alloimmunization rate of 30 percent, use of the Galileo would prevent approximately one alloimmunization every 5 to 6 years in this patient group. We conclude that the yield of preventing alloimmunization in this population by adding a second automated serologic testing platform is very low. Immunohematology 2013; 29:97–100.