The impact of an antibody investigation algorithm emphasizing specificity on reducing potential false-positive warm autoantibody detection at a Canadian tertiary care centre.

BACKGROUND AND OBJECTIVES: To reduce potential false-positive warm autoantibody (WAA) by solid-phase red cell adherence assay (SPRCA), our centre implemented a new antibody investigation algorithm (AIA) by classifying cases with panreactive SPRCA but negative saline-indirect antiglobulin test as 'antibody of undetermined significance' (AUS) after excluding clinically significant antibodies. We assessed the effects of the new AIA and subsequent alloantibody formation in patients with AUS. MATERIALS AND METHODS: Samples from patients with positive SPRCA screens between 1 September 2017 and 31 August 2021 were selected for the study. Frequencies of antibodies classified by the old and new AIAs were compared using Fisher's exact test. Patient demographics, transfusion history and antibody formation in cases of AUS were collected. RESULTS: A significant reduction in potential WAA frequencies from 127/1167 (11%) to 53/854 (6%) was observed (p < 0.001) when compared between the old and new AIAs among 2021 positive SPRCA antibody screens. While no patients with AUS later transitioned to potential WAA using the new AIA, four patients developed alloantibodies, including anti-E, anti-C, both anti-C and anti-E, and anti-Wra . CONCLUSION: A significant reduction in the frequencies of potential false-positive WAA detection at our centre was observed after implementing the new AIA, leading to less resource and phenotypically matched red blood cell (RBC) use. Some patients still developed subsequent RBC alloimmunization, so clinically relevant alloantibodies should be carefully excluded before determining AUS, taking forming or evanescent antibodies into consideration.

An Adjusted Process to Improve Efficiency and Efficacy of Adsorption Procedures to Resolve Warm Autoantibody Cases.

OBJECTIVE: The presence of warm autoantibodies in patient plasma typically causes extended delays in patient care due to panreactive antibody identification tests. Adsorption is the primary method for resolution. A modified adsorption procedure was devised with the intent to minimize delays, and the aim of the study was to evaluate its efficacy. METHODS: To evaluate the in-house developed (experimental) adsorption method, specimens were tested in parallel with the standard adsorption method described in the AABB Technical Manual, 20th edition. Specimens selected demonstrated panreactivity at the submitting facility and contained adequate volume for parallel adsorption studies. RESULTS: Ninety specimens were tested with both methods. Ninety specimens achieved complete adsorption with the experimental method and 88 specimens achieved complete adsorption with the standard method. Two underlying alloantibodies, which have been reported to cause hemolytic transfusion reactions and potential renal graft rejection, were detected using the experimental method that the standard method failed to detect. CONCLUSION: The experimental method demonstrated a significant reduction in rounds of adsorption required to resolve warm autoantibody reactivity, enhanced antibody detection ability with adsorbed plasma, and more cost-effective outcomes compared to the standard method. A follow-up study is planned to assess whether the incubation time can be decreased with the experimental method to further improve the efficiency of the method without sacrificing efficacy.

How to eliminate the interference of warm autoantibodies with antibody identification / 中国输血杂志

【Objective】 To investigate the effect of serological methods for eliminating the interference of warm autoantibodies with the compatibility test before blood transfusion. 【Methods】 The blood samples (whole blood and serum, 3 mL/each) of 10 cases of warm autoantibodies interfering with antibody screening and identification were collected. Autogenous or allogeneic red blood cells(RBCs) were treated with microthermal(45 ℃), chloroquine, or ZZAP (dithiothreitol and papain) reagents, and then were used to absorb the autoantibodies in patients′ plasma. The plasma after absorption and RBC elution were used for antibody identification by anti-human globulin method or Polybrene method to determine the specificity of the autoantibody/alloantibody. Blood transfusion with ABO/Rh homotypic RBCs without corresponding antigens was performed in patients with alloantibodies or specific autoantibodies, and the efficacy of blood transfusion was evaluated. 【Results】 The interferenc of warm autoantibodies with antibody screening and identification due to primary or secondary autoimmune diseases were eliminated after absorption, and IgG isospecific antibodies (anti-E, anti-Jka, anti-Wra) in 3 cases and specific autoantibodies (anti-Ce) in 1 case were yielded. 6 of the 10 patients received blood transfusion, and 4 with specific antibodies avoided exposure to corresponding antigens. After transfusion of 2U suspended RBCs, the increase of hemoglobin at 24h in all 6 patients was greater than 10 g/L, and no hemolytic transfusion reaction occurred. Anemia symptoms were improved after transfusion. 【Conclusion】 Appropriate elution methods and autologous/allogeneic absorption methods can eliminate the interference of warm autoantibodies with the identification of alloantibodies, therefore can accurately identify the types and properties of antibodies, thus providing targeted and effective blood transfusion.

Red-blood-cell alloimmunization and prophylactic antigen matching for transfusion in patients with warm autoantibodies.

BACKGROUND: Warm autoantibodies (WAA) are antibodies that react with an antigen on a patient's own red-blood-cells and can complicate compatibility testing whether or not they cause clinical haemolysis. The goal of this study was to understand the overall prevalence of WAA, the risk of RBC alloimmunization and determine whether RBC selection practices have an impact on alloimmunization. MATERIALS AND METHODS: Records of patients (>1 year of age) with an indirect antibody detection test (IAT) and serologic evidence of WAA over a 10-year-period were included. Eight centres from 5 countries collectively reviewed 1 122 245 patients who had an IAT. RESULTS: Of patients having IAT, 1214 had WAA (0·17%). Transfusion information for 1002 of the patients was available; 631 were transfused after identification of the WAA (63%); of the transfused patients, 390 received prophylactic antigen-matched (PAM) RBCs and 241 did not. Of the 372 patients with WAA who were transfused and had serologic testing 30+ days following transfusion (30-2765 days), 56 developed new RBC alloimmunization (15·1%). Patients who were transfused using a PAM strategy were not protected from new RBC alloimmunization [14·6% (31 of 212 patients) having PAM transfusion approach compared with those not receiving PAM approach (15·6%, 25 of 160 patients, P = 0·8837)]. CONCLUSIONS: The prevalence of WAA in patients having an IAT is low (<1%). A significant portion of patients with WAA form new RBC alloimmunization (15·1%); however, the use of PAM approach for RBC selection was not found to be protective against new alloimmunization.

Alloimmunization in autoimmune hemolytic anemia patient: The differential adsorption approach.

Patients of ß-thalassemia major are dependent on regular blood transfusions for their entire lifetime. Development of antibodies against red blood cell (RBC) antigen which may be alloantibody or autoantibody, several times as a result of frequent red cell component transfusions, further complicates the subsequent transfusion therapy. Among the autoantibodies, warm-reactive autoantibodies are commoner and interfere in the pretransfusion testing. These RBC autoantibodies present in patient's serum potentially react with all the cells of antibody identification panel giving "pan-reactive" picture and making alloantibody identification complex. In this report, we present our approach in a thalassemia patient who presented with warm-type autoimmune hemolytic anemia, low hemoglobin of 5.8 g/dl, and three significant alloantibodies (anti-D, anti-S, and anti-Jkb) which were masked by pan-reactive warm autoantibody(s). Differential adsorption was used to unmask underlying alloantibodies. We suggest that differential adsorption procedure is an effective and efficient method for autoantibody adsorption, detection, and identification of masked alloantibody(s), especially in patients with low hemoglobin and history of recent blood transfusion.

Process solution of autoantibodies in patients of autoimmune hemolytic anemia / 国际检验医学杂志

Objective Serological characteristic analysis for patients with autoimmune hemolytic anemia(AIHA)who has cold and warm auto‐antibody when undergoing blood type and cross‐matching .Methods Choosed 3 donors of red blood cells of group O to absorb autoantibodies of the patient′s serum(by using the methods of cold absorption) and used 2‐mercaptoethanol(2‐Me) to de‐stroyed the IgM antibody .Results The patient of AIHA blood type was B+ .There was cold and warm auto‐antibody in the pa‐tient′s serum ,and the result of cross‐matching is incompatible .Conclusion The patient′s serum contains cold and warm auto‐anti‐body which interferes blood type and cross‐matching .In emergency ,considering the patients condition ,blood transfusion combined with the drug treatment could achieve good effects .

Drug-induced autoimmune hemolytic anemia in a 78-year-old African-American man with chronic lymphocytic leukemia.

PATIENT: 78-year-old African-American man. PAST MEDICAL HISTORY: Chronic lymphocytic leukemia first diagnosed in 2003, with a subsequent relapse in 2006 and another in 2010. HISTORY OF PRESENT ILLNESS: In late 2011, the patient was admitted to the hospital for cholelithiasis, at which time his treating physician incidentally discovered severe anemia. The anemia worsened as time went on, and the patient became transfusion dependent. Hypogammaglobulinemia secondary to chronic lymphocytic leukemia (CLL) required that the patient receive intravenous immunoglobulin. Despite transfusion therapy, the anemia failed to lessen; laboratory results eventually led to the diagnosis of a drug-induced warm autoantibody that triggered hemolytic anemia. MEDICATIONS: The patient had taken rituximab in 2003; rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone (R-CHOP) in 2006; fludarabine, cyclophosphamide, and rituximab (FCR) in 2010; and intravenous Immunoglobulin (IVIG) and prednisone in 2011.

Auto-antibody Showing Anti-Fy(b) Specificity as Proven by the Dilution Method in the Presence of Warm Autoantibodies: A Case Report / 대한수혈학회지

Several approaches have been introduced to detect allo-antibodies in the presence of warm auto-antibodies, and these methods include warm autoadsorption, cysteine-activated papain and dithiothreitol (ZZAP), and polyethylene glycol (PEG) and dilution of the patient's serum. Among them, the dilution technique is a simple and rapid method. During pretransfusion testing of a 33 year-old systemic lupus erythematosus (SLE) patient with warm auto-antibodies, antibody identification was done by the dilution technique with using serum diluted 1-in-8. The patient demonstrated an anti-Fy(b) pattern of reactivity in his sera. Contrary to our expectations, the phenotype of the erythrocytes was Fy(a+/b+) and the genotype, as assessed by performing PCR-restriction fragment length polymorphism (RFLP), was FY*A/FY*B. These results suggest that the antibody is an autoantibody showing anti-Fy(b) specificities. An antibody identification test using undiluted serum showed the same result when 40 days had passed. We report here on a case with auto-anti-Fy(b) proven by the dilution method in the presence of warm autoantibodies.