[Evaluation of different prognostic markers in dogs with primary immune-mediated hemolytic anemia]

Canine primary immune-mediated hemolytic anemia (IMHA) is associated with a high mortality rate. Hypothesis of this study was that laboratory parameters not only determined initially but also in the course of the disease might be useful as prognostic markers. Included in the study were dogs with primary IMHA. Inclusion criteria were anemia (PCV < 0.30 L/L), a positive Coombs'test or persistent autoagglutination of erythrocytes, and the exclusion of underlying diseases. Dogs were divided into two groups based on survival: dogs that were still alive 14 days after start of treatment (group 1) and dogs that died or were euthanized before day 14 (group 2). Hematological and biochemical analyses as well as a coagulation profile were performed initially and on day 3. Out of 37 dogs with primary IMHA 28 belonged to group 1 and 9 to group 2. Significantly associated with mortality were thrombocytopenia (p = 0.001), lymphopenia (p = 0.026), a prolonged PT (p = 0.003) and aPTT (p = 0.005), hypofibrinogenemia (p = 0.028), disseminated intravascular coagulation (DIC) (p = 0.019), and high plasma ALT (p = 0.003) and AST (p = 0.004) plasma activities on initial presentation, as well as a decrease in hemoglobin (p = 0.034) and an increase in WBC count (p = 0.034), plasma bilirubin (p = 0.012) and urea concentration (p = 0.003) between day 0 and 3. In conclusion various laboratory parameters were useful as prognostic

[Autoimmune hemolytic anemia]

Diagnosis of autoimmune hemolytic anemia (AIHA) requires both serologic evidence of an autoantibody and hemolysis. Based on the characteristic temperature reactivity of the autoantibody to red cell membranes, AIHA is classified into warm AIHA or cold AIHA (cold agglutinin disease and paroxysmal cold hemoglobinuria). Sensitized RBCs are destructed by intravascular and/or extravascular hemolysis. On the basis of etiology, AIHA are classified as idiopathic or secondary. The common cause of secondary AIHA is lymphoproliferative disorders, autoimmune diseases, and infections. The first line therapy of patients with warm AIHA is glucocorticoids and primary treatment for cold AIHA is avoiding cold exposure. The other standard treatments include splenectomy and immunosuppressive drugs. Recently, rituximab, a monoclonal anti-CD20 antibody, has been used in refractory AIHA with excellent responses.

Detection of serum hemolysins in autoimmune hemolytic anemia

BACKGROUND

Some patients with autoimmune hemolytic anemia (AIHA) have in their sera autohemolysins able to hemolyze RBCs in vitro by activation of complement. We describe three autohemolysins in patients with AIHA and we study clinical correlations.

STUDY DESIGN AND METHODS

Thirty-two patients with AIHA were explored by immuno-hematological investigations (DAT, elution and serum testing).

RESULTS

Three autohemolysins were detected in three patients. All of these autoantibodies were likely IgM and reacted in vitro only with enzyme-treated RBCs. Two warm autohemolysins were detected in patients with warm-type AIHA. The first one was active at neutral pH with low title. The second, having a wide thermal amplitude reacting at 22 degrees C and a title of 16, was acid. The hemolysin detected in patient 3 with cold hemagglutinin disease, was active at 4 and 22 degrees C, at acid pH. The thermal optimum was 4 degrees C and the title 64. It was also detected at 37 degrees C with the same title, but only at neutral pH.

CONCLUSION

Although these autohemolysins were incomplete, hemolyzing in vitro only enzyme-treated RBCs, they were associated for the three patients with severe hemolysis.

Warm autoimmune hemolytic anemia is an IgM–IgG immune complex disease

Warm autoimmune hemolytic anemia (WAIHA) is characterized by polyclonal IgG autoantibodies binding to red blood cells (RBC). The characterization of the autoantigen in WAIHA has not yet led to definitive results, and the etiology of RBC autoantibodies remains unclear. An altered control of self-reactive IgG by autologous IgM has been proposed as the underlying mechanism of disease in WAIHA, suggesting that IgM-IgG immune complexes contribute to the pathophysiology of the disease. In the present study, we purified and characterized IgM from plasma of WAIHA patients and from healthy controls using FPLC-based protocols and optical biosensor technology, and investigated IgG present within the IgM fractions. We provide evidence that IgM-IgG immune complexes in plasma and associated with the RBC membrane are the characteristic feature of WAIHA, independent of the etiology of the disease. IgM-IgG immune complexes of WAIHA patients differ from IgM-IgG immune complexes of healthy individuals with regard to quantity and to structural composition. The data suggest that self-immunoglobulin is the original autoantigen underlying WAIHA. The molecular characterization of IgM-IgG immune complexes may define new targets for therapeutic intervention in WAIHA.

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.

Treatment of autoimmune hemolytic anemias

Treatment of autoimmune hemolytic anemias varies depending on whether the patient has autoimmune hemolytic anemia of warm antibody type, cold agglutinin syndrome, paroxysmal cold hemoglobinuria, or autoimmune hemolytic anemia secondary to an underlying disorder. Initial therapy for warm antibody autoimmune hemolytic anemia should be corticosteroids, such as prednisone at conventional doses of 1 to 1.5 mg/kg/d orally. Criteria must be established to determine whether the therapeutic response is adequate, because long-term therapy may lead to significant detrimental side effects. Splenectomy has the advantage over therapeutic options in that it has the potential for complete and long-term remission. The major adverse effect is the syndrome of overwhelming postsplenectomy infection. Other therapeutic options, which are less likely to have long-term benefit, are immunosuppressive drugs, danazol, intravenous immunoglobulin, and plasma exchange. Therapy of cold agglutinin syndrome often is unsatisfactory. All patients should avoid exposure to cold, and if additional therapy is necessary, the therapies used for warm antibody autoimmune hemolytic anemia may be tried with less likelihood of response. Paroxysmal cold hemoglobinuria requires aggressive supportive therapy, generally supplemented by corticosteroids. Hemolysis usually terminates spontaneously. Patients with secondary autoimmune hemolytic anemia may be treated similarly to those with idiopathic autoimmune hemolytic anemia, and additional therapy for the underlying disorder also may result in remission of the hemolysis.

Autoimmune hemolytic anemias: characteristics and classification

AIHAs may be caused by either IgG or IgM class antibodies which affects the presentation and severity of the hemolytic process. In addition, the IHA may be idiopathic or secondary in etiology. Resolution of underlying diseases in the secondary type will often resolve the hemolysis; however, treatment may require more than one course of action, especially in the WAIHAs.

Autoimmune hemolytic anemia

Six types of autoimmune hemolytic anemias have been described. Table 1 provides summary highlights for each type of AIHA. WAIHA accounts for the majority of cases, followed by CAIHA and DIAHA. In recent years, AIHA status post-BMT has been noted to occur more often than previously reported, particularly in T-cell-depleted graft recipients. The clinical presentation is diverse among the various types of AIHAs: WAIHA cases may require a complex treatment regimen if unstable hemolytic anemia is present, and often permanent remission is infrequent. In contrast, CAIHA in younger patients (status postinfection) is frequently asymptomatic and self-limiting. If AIHA is suspected in a patient with clinically significant presentation, it is important to communicate with the transfusion service since specific tests to confirm these diagnoses are not routinely done. Special procedures may be necessary to identify underlying rbc alloantibodies prior to transfusion. In a patient pre-operative for cardiopulmonary-bypass surgery, CAIHA antibody testing should be done. When found, pre-operative management may lessen the risk of serious consequences such as hemolysis, renal failure, and myocardial damage. AIHA associated in BMT recipients is frequently severe, and, in some cases may be refractory to treatment despite complex management strategies. Further studies are needed to acquire a better understanding of the pathogenesis of BMT-associated AIHA.

[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.

[A new approach for diagnosis of autoimmune hemolytic anemia]

Sixty four cases of autoimmune hemolytic anemia (AIHA) referred to our laboratory from 1985 to 1993 consisted of 51 warm type AIHA, 9 cold agglutinin disease (CAD), one paroxysmal cold hemoglobinuria, and 3 mixed type AIHA. There were 5 patients who had all clinical features of AIHA except for a positive direct-antiglobulin test (DAT). These patients were diagnosed as DAT-negative AIHA because of the elevation of red blood cell-associated IgG (RBC-IgG). The mean RBC-IgG of 100 healthy individuals was 33 +/- 13 (SD) molecules per one RBC. On the other hand, the RBC-IgG of patients with DAT-positive and with DAT-negative warm type AIHA were ranged from 257 to 12,421 and from 126 to 256 molecules per one RBC, respectively. One of 9 patients with CAD had a hemolytic anemia associated with only a cold agglutinin titer of 32 using saline-suspended RBCs, but a titer of 4,096 in the presence of bovine albumin. This case was diagnosed as low titer CAD. All of patients with DAT-negative AIHA or low titer CAD showed a good response to corticosteroid treatment.

[Immune hemolytic anemia induced by drugs]

Drugs may induce immune destruction of red blood cells through either autoantibody formation or antibody formation against the drug or its metabolites. In the former scheme the drug is believed to induce autoimmunization by causing some central dysregulation of the immune system the mechanism of which is still unclear. In the latter, data have been accumulating during the last decade pertaining to clinical manifestations, incriminated drugs, and immunohematologic diagnosis. The sharp specificity and individual variations of drug specific antibodies as well as the recognition of the receptor role of red cell blood group antigens explaining the involvement of red cells in drug-antidrug complexes are among the recent achievements in the knowledge of these anemias.

Autoimmune haemolysis: an 18-year study of 865 cases referred to a regional transfusion centre

Clinical and serological records of 865 patients with confirmed autoimmune haemolysis (AIH)--a much larger series than any previously reported--were critically reviewed nd analysed. A proposed new classification for AIH based on serological findings differs from traditional classifications in that a new category of "mixed" AIH has been defined in which both "warm" and "cold" autoantibodies are present, and both are capable of causing haemolysis. Patients in this mixed group tend to have severe disease that may run a chronic intermittent course. The presentation of cold agglutinin disease is much more variable than has been seen in previous studies, haemolysis due to low titre autoantibodies being common. The AIH associated with pregnancy, usually considered as being of bad prognosis, is often mild and self limiting in the absence of other associated disorders.

Serologic diagnosis in the differentiation of autoimmune hemolytic anemias

A complex serologic study was carried out in 20 patients with autoimmune hemolytic anemias (AIHA). The methods used were: the direct Coombs' test with specific sera anti IgG, IgM, IgA and complement (C), the direct and indirect test with papain treated erythrocytes (at 37 degrees C), determination of cold agglutinin titer and of warm and cold hemolysins. By these investigations using indigenous sera, the 20 cases of autoimmune hemolytic anemia could be classified: a) according to the thermal behaviour of autoantibodies, into warm antibody AIHA -- 15 cases, cold antibody AIHA -- 2 cases and both warm and cold antibody AIHA -- 3 cases; and b) according to the sensitizing globulin, into: IgG type -- 10 cases, IgG + C type -- 7 cases, IgG + IgM + C type -- 1 case, type C + cold agglutinins -- 2 cases.

Coombs--negative immune hemolytic anemia

An immune hemolytic anemia occurs in a few patients in whom the concentration of antibody on the red cell is below the level for detection by the usual antiglobulin test. Clinically, these patients are identical to patients with warm type Coombs-positive hemolytic anemia, except for the quantity of antibody on the cell. The course of the hemolytic disease is highly variable. It is postulated that the properties of the antibody in conjunction with the sensitivity of the reticuloendothelial system for antibody-coated cells account for hemolytic anemia occurring with such low concentrations of antibody. The response to steroid therapy and splenectomy, when indicated, is usually favorable.