Alloimmune hemolytic anemia

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Text of Alloimmune hemolytic anemia

  • 1. TABLE OF CONTENTS:ALLOIMMUNE HEMOLYTIC ANEMIA................................................................2INTRODUCTION:......................................................................................................2CLASSIFICATION OF IMMUNE HEMOLYTIC ANEMIA.................................3ALLOIMMUNIZATION FROM TRANSFUSION..................................................4CONSEQUENCES OF ALLOIMMUNIZATION TO BLOOD:.............................4PATHOPHYSIOLOGY:..............................................................................................6CLINICAL PRESENTATION:...................................................................................8LABORATORY STUDIES:........................................................................................9MANAGEMENT:.......................................................................................................10ALLOIMMUNIZATION DURING PREGNANCY (RhDALLOIMMUNIZATION).........................................................................................12BACKGROUND:.......................................................................................................13EPIDEMIOLOGY:....................................................................................................13PATHOPHYSIOLOGY:............................................................................................14CAUSES OF MATERNAL ALLOIMMUNIZATION:..........................................16HEMOLYTIC DISEASE OF INFANTS & NEWBORNS (HDFN)......................16PATHOPHYSIOLOGY:............................................................................................17CLINICAL PRESENTATION:.................................................................................17CAUSES:.....................................................................................................................18LABORATORY STUDIES:......................................................................................19MANAGEMENT:.......................................................................................................22DRUG INDUCED ALLOIMMUNIZATION..........................................................30PATHOGENESIS:......................................................................................................30SEROLOGICAL DIAGNOSIS:...............................................................................32 1
  • 2. REFERENCES:..........................................................................................................33 ALLOIMMUNE HEMOLYTIC ANEMIAINTRODUCTION:Alloimmunization is defined as, an immune response generated in an individual byan alloantigen from a different individual.In alloimmune hemolytic anemia, antibodies are produced against the red blood cellsa person receives in a blood transfusion. If the blood type used for the transfusion isdifferent than the recipients blood type, the recipients immune system can developantibodies that attack and destroy the transfused blood cells.Alloimmune antibodies also can develop as a result of the mixing of blood between apregnant woman and her baby at delivery. If the mothers blood type is Rh-negativeand the babys is Rh-positive, the mother can produce antibodies against the babysblood type. If a mother develops anti-Rh antibodies as a result of one pregnancy, theycan cross the placenta during the next pregnancy and harm the fetus. To prevent this, amedicine called RhoGam can be given at the time of delivery to block the mothersbody from developing antibodies against the babys blood type.Certain drugs can cause a reaction that develops into hemolytic anemia. These drugsinclude high doses of penicillin and related drugs, acetaminophen, quinine and otherdrugs to treat malaria, anti-inflammatory drugs, and levodopa.Thus Alloimmunization can be broadly divided into three main categories: 1. Alloimmunization after transfusion 2
  • 3. 2. Maternal Alloimmunization or iso-immunization 3. Drug induced alloimmunization CLASSIFICATION OF IMMUNE HEMOLYTIC ANEMIAAntigen Antibody Disease AssociationAutoimmune Warm antibody Primary Idiopathic Secondary Autoimmune disease(SLE) Lymphoprolifera tive disorders(EBV) Ovarian cysts Some cancers Drugs Cold antibody Cold haemagglutinin disease Cold antibody Infections, syndromes lymphoproliferat ive disorders Donath Paroxysmal cold Post viral & Landsteiner hemoglobinuria syphilisAlloimmune Induced by red cell Hemolytic transfusion antigens reactions HDN Post-stem cell allograft Drug dependent Antibody/macrophage mediated Antibody/complement mediated Membrane modification 3
  • 4. ALLOIMMUNIZATION FROM TRANSFUSIONAllogeneic blood transfusion is a form of temporary transplantation. This procedureintroduces a multitude of foreign antigens and living cells into the recipient thatpersist for a variable time. A recipient who is immuno-competent often mounts animmune response to the donor antigens, resulting in various clinical consequences,depending on the blood cells and specific antigens involved. The antigens mostcommonly involved are classified in the following categories: Human leukocyte antigens (HLAs) class I shared by platelets and leukocytes class II present on some leukocytes Granulocyte-specific antigens Platelet-specific antigens (human platelet antigen [HPA]) RBC-specific antigens.CONSEQUENCES OF ALLOIMMUNIZATION TO BLOOD:The consequences of alloimmunization to blood include the following clinicalmanifestations:Alloimmunization against RBCs Acute intravascular hemolytic transfusion reactions (rarely a consequence of alloimmunization and almost always caused by ABO antibodies) Delayed hemolytic transfusion reactions (DHTRs) (hemolysis caused by RBC all antibodies at least 24 hours post transfusion) 4
  • 5. Hemolytic disease in newborns (mothers alloimmunization against fetal antigens, most often resulting from previous pregnancies)Alloimmunization against platelets (platelet-specific or HLA class I antigens) Refractoriness to platelet transfusion (an increase in the platelet count after platelet transfusion that is significantly lower than expected e.g < 30% of predicted after 10-60 min or < 20% at 18-24h post transfusion) Post transfusion purpura (thrombocytopenia after transfusion of red cells or other platelet-containing products, associated with presence of platelet allo-antibodies) Neonatal alloimmune thrombocytopenia (mothers alloimmunization against fetal antigens, most often resulting from previous pregnancies)Alloimmunization against granulocytes (granulocyte-specific or HLA antigens)Refractoriness to granulocyte transfusion Febrile non-hemolytic transfusion reactions Transfusion-related acute lung injury (i-e a transfusion reaction in which donor HLA antibodies react against recipient antigens)Transplant rejection Alloimmunization against HLA antigens 5
  • 6. Alloimmunization against blood cell antigens (in bone marrow transplantation)DHTR and refractoriness to platelet transfusions are most important. Refractoriness togranulocyte transfusions involves either anti-HLA o