Autoimmune Hemolytic AnemiasDonald R. Branch, Ph.D.ScientistResearch & DevelopmentCanadian Blood ServicesToronto, Ontario CANADA
Lecture OutlineDiagnosis of hemolytic anemiasImmune hemolytic anemiasClassification of AIHAsSerological diagnosis of specific AIHAsSelection of blood for transfusing patients with AIHAsTransfusion of patients with AIHAs
No Need to be Terrified
- Diagnosis of Hemolytic AnemiaShortened red cell survival (
Tests to Diagnose AIHA Hemoglobin and hematocritRule-out bleeding/hereditary causes red cell morphology and blood filmReticulocyte countBilirubinSerum haptoglobinLDHOther tests (hemoglobinemia, hemosiderin)DAT!Cooperation between blood bank, hematology and urinalysis depts.
Increased Reticuloctye Count
Immune Hemolytic Anemias
DIRECT ANTIGLOBULINTESTTest for IgG and/or complement coating the patients red blood cells
Classification of Immune Hemolytic AnemiasAlloimmuneHTRDHTRHDFNAutoimmune hemolytic anemias (AIHAs)DAT-positiveDAT-negativeDrug-inducedAutoimmuneDrug-adsorptionImmune-complexBystander Immune CytolysisSickle cell hemolytic transfusion reaction syndrome Reactive hemolysis
Classification of AIHAs Warm Antibody AIHA (warm AIHA) Cold Antibody AIHA (cold agglutinin syndrome; CAS) Paroxysmal Cold Hemoglobinuria (PCH) Combined Cold and Warm (Mixed AIHA) Atypical AIHAAIHA with a Negative DATWarm Antibody AIHA Caused by IgM or IgA Autoantibodies Drug-Induced AIHA (drug-induced immune HA)
Serological Diagnosis of AIHA
Warm Antibody AIHA and DAT70% of all AIHA are warm type~80% of warm AIHA prefer oldest RBCs~20% have no preference for age of RBCs
Associated with IgG, (IgA), (IgM) autoantibodies:DAT: IgG + C (67%) IgG only (20%) C only (13%)
Must use a polyspecific antiglobulin reagent for DAT
Criteria for Diagnosis of Cold Antibody AIHAClinical findings indicative of acquired hemolytic anemia.Positive direct antiglobulin test with anti-C3d ONLY!Serum antibody optimally reactive at 4C but can react up to 30C, usually anti-I/i specificity
Criteria for Diagnosis of Mixed AIHAEvidence indicative of acquired hemolytic anemia.Severe hemolysis intravascular/extravascularDAT positive with BOTH IgG and C3d.Serum contains an IgG antibody reactive at 37C indistinguishable from warm autoantibody.Serum ALSO contains LOW TITER antibody reactive up to 30C (usually 37C) that is optimally reactive at 4C and is IgM; often shows anti-I/i.Eluate contains IgG antibody having same specificity as serum antibody.RESPONDS remarkably WELL to steroid therapy.
(Shulman IA, Branch DR, et al. Autoimmune hemolytic anemia with both coldand warm autoantibodies. JAMA 253:1746-1748, 1985)
Paroxysmal Cold Hemoglobinuria (PCH)Incidence: May be quite common in young children.Acute onset of severe hemolysis with hemoglobinemia and hemoglobinuria.(hemoglobinuria very common).Erythrophagocytosis by neutrophils is common and is distinctive.Donath-Landsteiner test is diagnostic.Patients have a stormy course but good ultimate prognosis.
Erythrophagocytosis in PCH RBC rosetting around neutrophils and erythrophagocytosis by neutrophils, rather than monocytes, are prominent findings in PCH. Rarely seen in other forms of immune hemolysis, where monocytes are usually involved. May be first clue to diagnosis.
The Donath-Landsteiner TestCharacteristics of Typical D-L Antibodies
Biphasic Hemolysin IgG Immunoglobulin Class Anti-P Specificity May also react by IAT
pP + complementP
DAT-negative AIHARareOften severe - fatalSometimes anti-IgA/anti-IgM usefulMononuclear phagocyte assay may be useful use patient monocytesOften responds to steroid treatment
Criteria for Diagnosis of DAT-negative AIHAEvidence indicative of acquired hemolytic anemia.DAT negative with anti-IgG/anti-C3dNo unexpected antibodies detectable in serum or eluate (sometimes antibody can be detected in eluate)Responds to prednisone treatment
Specificity of Warm AutoantibodiesAnti-Rh-like specificityAnti-e or anti-E (SIMPLE SPECIFICITY)Anti-pdl does not react with D- or Rhnull Anti-dl does not react with RhnullRelative Rh specificity titration studiesType I or Type II AutoantibodiesOther blood groups Kell, Gerbich (high frequency antigens)
Not Usually Necessary Academic Exercise
A Guide to Transfusion of Patients with Autoimmune Hemolytic Anemia
No Need to Hide When a Patient Presents with AIHA
Important PrinciplesIndications for transfusion are not significantly different than for similarly anemic patients without AIHA.Specialized laboratory procedures are necessary. Critical to look for alloantibodiesCommunication between laboratory personnel and clinicians is critical.
Provision of Safe Blood
Risks of Transfusion in AIHAAutoantibody will cause shortened survival of transfused RBC.Alloantibodies may be present in addition to the autoantibody. Must Be Identified and Antigen-Negative Blood Given!Risks caused by the increase in RBC mass as a result of transfusion.
Blood Transfusion in Autoimmune Hemolytic Anemia Blood should never be denied a patient with a justifiable need, even though the compatibility test may be strongly positive. Probably the most common mistake is reluctance to transfuse even those patients with severe anemia.
Communication Between Clinician and Transfusion ServiceResponsibilities of Transfusion ServiceInitiate communication.Indicate extent of compatibility testing performed, e.g., auto- or alloadsorption.Clinician should be assured that, after appropriate compatibility testing, an acute HTR is unlikely.Indicate that RBCs will provide temporary benefit even if they do not survive normally because of the patients autoantibody.
Communication Between Clinician and Transfusion ServiceResponsibilities of ClinicianIndicate urgency of situation.Understand principles of compatibility testing.Seek assurance that appropriate compatibility testing is to be performed.
Indications for TransfusionA common mistake is reluctance to transfuse patients with AIHA.If appropriate compatibility procedures are performed, survival of transfused RBCs is generally about as good as that of the patients own RBCs. Alloantibodies MUST be ruled out!Significant temporary benefit is to be expected.Patients should not be denied transfusion because of an RBC autoantibody.
American Journal of Clinical Pathology 1982; 78(2):161-167
ABO and RhIgG auto - Treat cells with ZZAP to remove autoantibody and retypeIgM auto warm everything to 37C and retype or ZZAP treat and retypeSpontaneous Agglutination(Branch DR, Petz LD. A new reagent (ZZAP) having multiple applications in immunohematology. Am J Clin Pathol. 78:161-167, 1982)
RBC ALLOANTIBODIES IN PATIENTS WITH WARM AUTOANTIBODIES #ANTIBODIES/ % OF SERA REFERENCE #SERA TESTED WITH ALLOABS Morel 8/20 40 Branch and Petz 5/14 36Wallhermfechtel et al 19/125 15Laine and Beattie 41/109 38James et al 13/41 32Issitt et al (alloadsorptions) 13/34 38Issitt et al (autoadsorptions) 5/41 12Leger and Garratty 105/263 40 _______ TOTALS: 209/ 647 32%
(Branch DR, Petz LD: Detecting alloantibodies in patients with autoantibodies. Transfusion 39:6-10, 1999) (editorial)
Adsorption ProceduresWarm autoadsorption using ZZAP is the optimal procedure for alloantibody detection.One should obtain adequate volumes of patients RBCs to perform the procedure.RBCs should be retained for subsequent procedures.The number of ZZAP autoadsorptions needed is variable depending on the strength of the IAT and the ability to reduce the DAT.Usually 2 adsorptions is sufficientAutoadsorption is not reliable in a recently transfused patient.
If patients RBCs are not available for autoadsoprtion.If the patient has been transfused recently, and if the patients pre-transfusion RBCs are not available for autoadsorption.
Selection of Red Cells for Allogeneic AdsorptionR1R1R2R2rrOne cell Jk(a-)Another cell Jk(b-)Use ZZAP to denature other important antigens
Allogeneic AdsorptionAdvance planning is important !Large aliquots of appropriately phenotyped RBC should be obtained, treated with ZZAP, and stored at 4oC for up to 2 months.If such procedures are infrequent, cryopreservation may be preferable.Phenotyping patient may make it feasible to use fewer cells in adsorptions.
Single-Cell Allogeneic Adsorption
Cold Antibody AIHAPerform compatibility tests at 37oC.In a small pe