Transfusion Therapy for Autoimmune Hemolytic Anemia Patients: A Laboratory Perspective

Extract

Patients presenting with autoimmune hemolytic anemias create inherent challenges to those tasked with providing compatible blood for transfusion therapy. These patients have developed autoantibodies against their own red cell surface antigens. Because these antigens are usually high-incidence, these patients will typically demonstrate panagglutination when their serum is exposed to most commercially procured screening red blood cells. This makes the identification of clinically significant alloantibodies difficult for laboratory personnel. Transfusion history, patient phenotype availability, and previous antibody records all impact the testing methods. The end goal is to identify clinically significant alloantibodies in order to provide antigen negative, compatible red blood cells, which reduces the risk of transfusion related reactions. It is imperative to understand the laboratory results and the techniques available that guide the investigative process.

Immune hemolytic anemia (IHA) results from an immune mediated response to red blood cell (RBC) surface antigens. Based on the class of antibody, predominantly immunoglobulin G (IgG) and immunoglobulin M (IgM), patients may experience varying degrees of hemolyis. The immunological response may result in complement fixation or subsequent RBC destruction by the splenic macrophages. Though various classifications and sub-classifications exist, the AABB has divided IHAs into three main classes: autoimmune hemolytic anemias (AIHA), drug-induced hemolytic anemias, and alloimmune hemolytic anemias.¹ Regardless of the type of anemia, most patients present with diverse, non-specific symptoms that may include dyspnea, pallor, weakness, fatigue, dizziness, abdominal pain, weight loss, and jaundice.^2,3

In order to effectively manage the technological methodologies employed in the attainment of compatible RBCs for these…

ABBREVIATIONS: AHG = anti-human globulin; AIHA = autoimmune hemolytic anemia; CAS = cold agglutinin syndrome; DAT = direct antiglobulin test; HDN = hemolytic disease of the newborn; IAT = indirect antiglobulin test; IHA = immune hemolytic anemia; LISS = low ionic strength solution; PAM = prophylactic antigen-matched; PCH = paroxysmal cold hemoglobinuria; PEG = polyethylene glycol; RBC = red blood cell; WAIHA = warm autoimmune hemolytic anemia.