Characterization of autoantibodies in mixed-type autoimmune hemolytic anemia

Immunohematological and clinical characterizations of mixed autoimmune hemolytic anemia

BACKGROUND AND AIM:

Patients with warm autoimmune hemolytic anemia (AIHA) may carry immunoglobulin (Ig) M antibodies that react at room temperature and are nonpathological, but few may have cold agglutinins that react at or above 30°C and are referred to as “mixed” AIHA (MAIHA). Here, we present our experience on characterizing MAIHA both clinically and serologically.

MATERIALS AND METHODS:

Out of 134 AIHA patients, 13 diagnosed as MAIHA were subjected to detailed immunohematological characterization. Most patients were severely anemic and required urgent transfusions. Resolution of blood group discrepancy, elution, Donath-Landsteiner test, and adsorption study were performed following established protocol. “Best match” blood units were selected and transfused to patients.

RESULTS:

Eight of the 13 patients had severe hemolysis. The median age of patient was 37 years with a female preponderance and secondary MAIHA was observed in 8 (61.5%) patients. Blood group discrepancy was encountered in 4 (30.8%) patients. Multiple red cell bound autoantibodies and high titer serum-free IgM autoantibodies were detected in all samples. Twenty-nine units of “best match” packed red blood cells were transfused to 12 patients without any adverse reaction. Improvement in hematological and biochemical values was observed in all follow-up patients.

CONCLUSION:

Patients with MAIHA often present with severe hemolysis necessitating blood transfusions. While red cells are coated with multiple autoantibodies, both warm reactive IgG and cold reactive IgM autoantibodies are present in the serum. These serological complexities not only render a crossmatch incompatibility but often lead to blood group discrepancy. “Best match” blood transfusion is always lifesaving.

Systemic lupus erythematosus presenting with mixed-type fulminant autoimmune hemolytic anemia

We report the case of a 9-year-old girl who presented with mixed-type fulminant autoimmune hemolytic anemia (AIHA) at the onset of systemic lupus erythematosus (SLE). On admission, laboratory investigations indicated very severe anemia (Hb, 2.7 g/dL) with reticulocytosis and positive direct/indirect Coombs tests. In addition, agglutinative reaction was clinically observed. Based on further examinations, the patient was diagnosed with AIHA complicated with SLE, and mixed-type AIHA was clinically identified. With oral prednisolone and methylprednisolone pulse therapy, the patient entered remission.

Postoperative Recurrence of Invasive Thymoma with Cold Agglutinin Disease and Autoimmune Hemolytic Anemia

A 50-year-old man presented to our hospital in 1995. Invasive thymoma was diagnosed and extended thymectomy and left upper lobe partial resection were performed. In 2013, he complained of dyspnea. Chest computed tomography showed postoperative recurrence of invasive thymoma. Several chemotherapies were administered. Severe anemia and an increase in the total bilirubin level were observed with chemotherapies. In additional, an examination showed that the direct Coombs test was positive. Cold agglutinin was also high. We herein experienced a rare case of postoperative recurrence of invasive thymoma with cold agglutinin disease and autoimmune hemolytic anemia.

Autoimmune hemolytic anemia: From lab to bedside

Autoimmune hemolytic anemia (AIHA) is not an uncommon clinical disorder and requires advanced, efficient immunohematological and transfusion support. Many AIHA patients have underlying disorder and therefore, it is incumbent upon the clinician to investigate these patients in detail, as the underlying condition can be of a serious nature such as lymphoproliferative disorder or connective tissue disorder. Despite advances in transfusion medicine, simple immunohematological test such as direct antiglobulin test (DAT) still remains the diagnostic hallmark of AIHA. The sensitive gel technology has enabled the immunohematologist not only to diagnose serologically such patients, but also to characterize red cell bound autoantibodies with regard to their class, subclass and titer in a rapid and simplified way. Detailed characterization of autoantibodies is important, as there is a relationship between in vivo hemolysis and strength of DAT; red cell bound multiple immunoglobulins, immunoglobulin G subclass and titer. Transfusing AIHA patient is a challenge to the immunohematologist as it is encountered with difficulties in ABO grouping and cross matching requiring specialized serological tests such as alloadsorption or autoadsorption. At times, it may be almost impossible to find a fully matched unit to transfuse these patients. However, transfusion should not be withheld in a critically ill patient even in the absence of compatible blood. The “best match” or “least incompatible units” can be transfused to such patients under close supervision without any serious side-effects. All blood banks should have the facilities to perform the necessary investigations required to issue “best match” packed red blood cells in AIHA. Specialized techniques such as elution and adsorption, which at times are helpful in enhancing blood safety in AIHA should be established in all transfusion services.

Hemolytic anemia due to warm autoantibodies

The diagnosis of autoimmune hemolytic anemia (AHA) requires evidence of shortened red blood cell (RBC) survival mediated by autoantibodies directed against autologous RBCs. About 80 percent of patients with AHA have warm-reactive antibodies of the IgG isotype; the remainder exhibit cold-reactive autoantibodies. Typical patients exhibit anemia, reticulocytosis, spherocytes and polychromasia on the blood film and a positive direct antiglobulin test (DAT). Increased indirect serum bilirubin, urinary urobilinogen and serum lactate dehydrogenase (LDH), and decreased serum haptoglobin are not required for the diagnosis, but are frequently present. Patients with AHA and no underlying associated disease are said to have primary or idiopathic AHA. AHA in patients with associated autoimmune disease and certain malignant or infectious diseases is classified as secondary. The etiology of AHA is unknown. Patients with symptomatic anemia require transfusion of RBCs. Prednisone and splenectomy may provide long term remission. Rituximab, intravenous immunoglobulin, immunosuppressive drugs and danazol have been effective in refractory cases and for patients who are poor candidates for surgery.

Investigation of the mechanism of drug-induced autoimmune hemolytic anemia in cynomolgus monkeys elicited by a repeated-dose of a humanized monoclonal antibody drug

We investigated the mechanism of hemolytic anemia detected in a repeated-dose toxicity study using cynomolgus monkeys that were treated with a humanized antibody drug. This drug was an IgG1 monoclonal antibody (MoAb) that binds to the human HM1.24 antigen named anti-HM1.24 MoAb. The presence of the HM1.24 antigen on the erythrocyte membranes and the erythrocyte agglutination following the addition of anti-HM1.24 MoAb was examined. In addition, an indirect Coombs' test, a hemolysis assay and the measurement of anti-single stranded-DNA antibodies were performed using test animal serum or plasma. The specific binding of FITC- and 125I-labeled anti-HM1.24 MoAb to the erythrocyte membrane was not observed. HM1.24 antigen was not identified on the erythrocyte membranes. However, a high concentration (more than 713 microg/mL) of anti-HM1.24 MoAb hemagglutinated the erythrocyte suspensions. The cause of this agglutination was unclear, but it is assumed that the non-specific binding and/or adhesion caused the direct agglutination. In the examination using test serum from the anemic monkeys, a positive reaction in the indirect Coombs' test was noted. Moreover, in these Coombs' test-positive animals, the production of anti-single stranded-DNA antibodies was sequentially increased. In the female monkey sacrificed in extremis due to severe anemia, an in vitro hemolytic reaction was detected attributable to complement activation. From these results, the hemolytic anemia detected in the repeated-dose toxicity study was diagnosed as a drug-induced autoimmune hemolytic anemia (AIHA) and the primary cause was assumed to be production of IgG class anti-erythrocyte autoantibodies.

Autoimmune hemolytic anemia

Red blood cell (RBC) autoantibodies are a relatively uncommon cause of anemia. However, autoimmune hemolytic anemia (AIHA) must be considered in the differential diagnosis of hemolytic anemias, especially if the patient has a concomitant lymphoproliferative disorder, autoimmune disease, or viral or mycoplasmal infection. Classifications of AIHA include warm AIHA, cold agglutinin syndrome, paroxysmal cold hemoglobinuria, mixed-type AIHA, and drug-induced AIHA. Characteristics of the autoantibodies are responsible for the various clinical entities. As a result, diagnosis is based on the clinical presentation and a serologic work-up. For each classification of AIHA, this review discusses the demographics, etiology, clinical presentation, laboratory evaluation, and treatment options.

Mixed-type auto-immune haemolytic anaemia in a patient with HIV infection

A young HIV-infected patient presented with a severe auto-immune haemolytic anaemia with both warm and cold auto-antibodies, an infrequent category of anti-erythrocyte auto-immunity. Serological findings were compatible with the presence of a low-titre, high-thermal-amplitude anti-I cold-reacting antibody and a pan-reactive warm-reactive auto-antibody. Immunochemical characterisation of the warm antibody failed to identify any membrane protein acting as auto-antigen. This is, to our knowledge, the first reported case of mixed-type auto-immune haemolytic anaemia in a patient with HIV infection. Overt haemolysis is a very rare complication in HIV-infected patients, despite the high prevalence of a positive direct antiglobulin test reported in these patients. This suggests that HIV infection is a condition in which anti-erythrocyte auto-immunity is a serological finding without haemolytic effects in the large majority of cases.

[Immunologic hemolytic anemia. From autoimmunity to anti-medication immunization]

The serological investigation of auto-immune hemolytic anemias based on the direct antiglobulin test, the study of the serum and the eluate allows a classification of the auto-immune hemolytic anemia which is still valid and correlates well with the clinical features. The use of new techniques should increase the sensitivity of the tests but also stress the problem of the frontier between physiological and pathological states. The use of monoclonal antibodies of defined specificity would be an useful tool for the immunohematological classification of the auto-immune hemolytic anemias. The addition of new therapeutical means should improve the prognosis of these anemias. The increasing consumption of drugs and the development of the investigations of the adverse reactions including the hemolytic anemias have allowed the emergence of new pathogenic concepts. The gravity of the clinical evolution of some of these immune hemolytic anemias stress the necessity of an adequate therapeutic survey and the development of new means of diagnostic. The clinicians should be aware of the possibility of cross reactivity for drug dependent antibodies with other components of related chemical structure.

Identification of autoantigens in autoimmune haemolytic anaemia by a non-radioisotope immunoprecipitation method

In human autoimmune anaemia (AIHA), warm autoantibodies frequently appear to have serological specificity for the Rh complex, but to date, immunochemical techniques have failed to demonstrate that the antibodies react with Rh-associated polypeptides. We describe the immunoprecipitation of red blood cell (RBC) autoantigens, using biotin labelling and a luminescent detection method. In three cases of warm AIHA, a band of 32 kD and a diffuse zone of 38-51 kD or 40-51 kD were specifically precipitated by eluted RBC autoantibody. This pattern corresponds closely with that precipitated by two Rh-specific monoclonal antibodies, BRIC 207 and AB5. Antibody from the three eluates also showed serological specificity for the Rh complex in a haemagglutination assay against a panel of RBC with a range of Rh phenotypes, including rare -D-/-D- and Rh null cells. Eluted autoantibody from another warm AIHA patient immunoprecipitated a peptide of 67 kD that did not correspond in apparent molecular mass either with Rh-associated bands, or with major RBC membrane proteins or sialoglycoproteins (SGP). The haemagglutination assay showed that this eluate contained both Rh-specific and Rh-unrelated antibody. Warm autoantibody eluted from the RBC of a clinically normal, but direct antiglobulin test positive, blood donor was serologically unreactive with the Rh complex, and immunoprecipitated unknown peptides of 26, 29, 35, 48 and 51 kD, together with a band of 90 kD that comigrated with SGP alpha 2 (glycophorin A). In six further warm AIHA cases, no antigens were precipitated by autoantibody-containing RBC eluates. Overall, the results demonstrate that autoantibodies bind to Rh polypeptides in some, but not all, patients with warm AIHA, suggesting that the aetiology of the disease may vary.