Autoimmune hemolytic anemia is a heterogeneous disease with respect to the type of the antibody involved and the absence or presence of an underlying condition. Treatment decisions should be based on careful diagnostic evaluation. Primary warm antibody autoimmune hemolytic anemias respond well to steroids, but most patients remain steroid-dependent, and many require second-line treatment. Currently, splenectomy can be regarded as the most effective and best-evaluated second-line therapy, but there are still only limited data on longterm efficacy and adverse effects. The monoclonal anti-CD20 antibody rituximab is another second-line therapy with documented short-term efficacy, but there is limited information on long-term efficacy and side effects. The efficacy of immunosuppressants is poorly evaluated. Primary cold antibody autoimmune hemolytic anemias respond well to rituximab but are resistant to steroids and splenectomy. The most common causes of secondary autoimmune hemolytic anemias are malignancies, immune diseases, or drugs. They may be treated in a way similar to primary autoimmune hemolytic anemias, by immunosuppressants or by treatment of the underlying disease.
IntroductionAutoimmune hemolytic anemia (AIHA) is a rare disease. In a recent population-based study 1 the incidence was 0.8/100 000/year, but the prevalence is 17/100 000. 2 Primary (idiopathic) AIHA is less frequent than secondary AIHA. Secondary cases are often challenging because not only AIHA but also the underlying disease(s) must be diagnosed and treated. AIHA is essentially diagnosed in the laboratory, and considerable improvement has been made in this field. However, progress in treatment has been much slower. [3][4][5][6][7][8] Therapy has been reviewed by several investigators, [8][9][10][11][12][13][14][15] but no treatment guidelines have yet been published.
DiagnosisThe diagnosis of AIHA is usually straightforward and made on the basis of the following laboratory findings: normocytic or macrocytic anemia, reticulocytosis, low serum haptoglobin levels, elevated lactate dehydrogenase (LDH) level, increased indirect bilirubin level, and a positive direct antiglobulin test with a broad-spectrum antibody against immunoglobulin and complement ( Figure 1). However, there are pitfalls, particularly in secondary cases, because not always are all of the typical laboratory findings of AIHA present. 15 Two pieces of information are of utmost importance for the clinician to make an appropriate treatment decision: (1) What type of the antibody is involved? (2) Is the AIHA primary or secondary? The type of antibody can be identified with the use of monospecific antibodies to immunoglobulin G (IgG) and C3d. When the red cells are coated with IgG or IgG plus C3d, the antibody is usually a warm antibody (warm antibody AIHA [WAIHA]). When the red cells are coated with C3d only, the antibody is often but not always a cold antibody. For definite diagnosis of a cold antibody AIHA (CAIHA), the cold agglutinin titer should be markedly elevated (Ͼ 1:512)...