Haemolytic Anaemia - H. LEE, HKMU PDF

HONG KONG METROPOLITAN UNIVERSITY SCI 3009SEF Haematology & Transfusion Science I H.LEE Haemolytic Anaemia 20-1-2025 H.LEE SCI 3009SEF 20/1/2025...

HONG KONG METROPOLITAN UNIVERSITY SCI 3009SEF Haematology & Transfusion Science I H.LEE Haemolytic Anaemia 20-1-2025 H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 1  Haemolytic anaemias (HA) Hemolytic anemias are defined as those anemias which result form an increase in the rate of red cell destruction. - In hemolytic disorders, red cells are destroyed prematurely - If the red blood cell life span is only moderately shortened, the patient will usually have little, if any, anemia because the bone marrow is capable of increasing the rate of new red blood cell production. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 2  Haemolytic anaemias (HA) Red cell destruction usually occurs after 120 days when the cells are removed extravasculary by the macrophages of the reticuloendothelial (RE) system, especially in the marrow but also in the liver and spleen. The breakdown of red cells liberates iron for recirculation via plasma transferrin to marrow erythroblasts, and protoporphyrin which is broken down to bilirubin. This circulates to the liver where it is conjugated to glucuronides which are excreted into the gut via bile and converted to stercobilinogen and stercobilin (excreted in feces). Stercobilinogen and stercobilin are partly reabsorbed and excreted in urine as urobilinogen and urobilin. A small fraction of protoporphyrin is converted to carbon monoxide (CO) and excreted via the lung. Globin chains are broken down to amino acids which are reutilized for general protein synthesis in the body. Haptoglobins are proteins present in normal plasma capable of binding hemoglobin. The hemoglobin-haptoglobin complex is removed from plasma by the RE system. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 3 JaypeeDigital/eBook Reader/Essentials in Hematology and Clinical Pathology H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 4  Haemolytic anaemias (HA) The major criteria for the laboratory diagnosis of hemolytic anemia are: - Reticulocytosis - Serum level of unconjugated/conjugated bilirubin. - Serum level of lactic dehydrogenase (LDH) is elevated. - Serum haptoglobin level is decreased. - The peripheral blood smear often but not invariably shows morphologic changes in the red blood cells compatible with hemolysis e.g. many spherocytes suggest hereditary spherocytosis or immunohemolytic anemia and sickle cells suggest one of the sickle cell syndromes. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 5  Haemolytic anaemias (HA) There are two general sites in which hemolysis may take place. 1. Intravascular hemolysis Red blood cells are destroyed directly within the circulatory system i.e. breakdown of red cells within blood vessels which plays little or no part in normal red cell destruction. 2. Extravascular hemolysis Is more common than intravascular hemolysis and involves the destruction of red blood cells within mononuclearphagocytic cells, often in the spleen. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 6  Haemolytic anaemias (HA) HA can be classified into : 1. Extrinsic HA - From a source outside the red cell; disorders extrinsic to the RBC are usually acquired. - The RBC may get damaged by chemicals, mechanical or physical agents or immune destruction. - Hemolysis can occur either intravascularly or extravascularly 2. Intrinsic HA - Due to defects of the RBC itself and are usually inherited. - The abnormality can be in the membrane, cell enzymes, or the hemoglobin molecule. - The cells that show intrinsic defects are hemolyzed extravascularly because the RBCs are not severely damaged H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 7  Extrinsic Haemolytic Anaemias Immune Haemolytic Anaemia (IHA) mediated by immune response especially humoral antibodies resulted in RBC shortened life span. IHA has 3 main types 1. Autoimmune HA (AIHA) , in which the patient makes an autoantibody against his or her own red cells; included both - Warm AIHA and Cold AIHA 2. Alloimmune, where the patient’s antibody is directed against foreign red cells; included -Hemolytic transfusion reactions -Hemolytic disease of the fetus and newborn 3. Drug-induced, where a drug-dependent or related antibody is responsible for hemolysis H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 8  Autoimmune Hemolytic Anaemia AIHA : Immune system lost its ability for self-recognition and antibodies are made to own RBCs and initiate haemolysis AIHA is characterized by premature RBC destruction caused by autoantibodies that bind to the RBC surface. In AIHA, the lost of T suppressor cell control resulting in the production of autoantibodies against RBC self- antigens. It is believed that the autoimmune disease occur because of a number of factors including genetic predisposition, exposure to infectious agents that can induce antibody production and defects in the mechanism regulating immune tolerance. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 9  Autoimmune Hemolytic Anaemia Warm AIHA The majority of the warm autoantibodies are of the IgG class optimal at 370C It cause extravascular hemolysis of the RBC. The red cells are usually coated with IgG alone, IgG and complement or complement alone, The complement component detectable is C3d, the degraded fragment of C3. The disease may occur at any age in either sex and presents as a hemolytic anemia of varying severity. About 60% of these cases are idiopathic, with the remaining percentage due to another underlying disease, such as lymphoma, chronic lymphocytic leukemia, viral infections and immunodeficiency syndromes, AIHA in SLE is typically of the IgG + complement type H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 10  Autoimmune Hemolytic Anaemia Warm AIHA Anaemia is moderate to severe Normochromic, normocytic with Polychromasia Spherocytes, schistocytes, etc may be seen indicating haemolysis Increase reticulocytosis Autoantibody presence Direct Coombs test (DAT) Positive - DAT tests for RBC sensitized with IgG antibody or complement H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 11  Autoimmune Hemolytic Anaemia Cold AIHA The majority of the cold autoantibodies are of the IgM class optimal below 370C Cold AIHA has 2 main type: - Cold Agglutinin Disease (CAD) - Paroxysmal Cold Haemoglobinuria H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 12  Autoimmune Hemolytic Anaemia Cold Agglutinin Disease (CAD) CAD occurs predominantly in older individuals with peak incidence after 50 years of age. Affects men and women equally. The antibodies in this disorder show the greatest reactivity with antigens at temperatures below 300 C. These antibodies are usually of the IgM class and they bind complement. Cases of cold agglutinin disease can be idiopathic or secondary to another underlying condition, such as infections with Mycoplasma pneumoniae or Infectious mononucleosis. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 13 Autoimmune Hemolytic Anaemia Cold Agglutinin Disease (CAD) Hemolytic syndromes of varying severity may occur depending on the titer of the antibody in the serum, its affinity for red cells, its ability to bind complement, and its thermal amplitude The cold IgM antibody may dissociate from red cells when they pass to the warmer central circulation but complement remains bounding leading to be destroyed in the whole RE system, especially the liver, giving rise to a chronic haemolytic anemia DAT remains positive-of complement only type H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 14  Autoimmune Hemolytic Anaemia Paroxysmal Cold Haemoglobinuria (PCH) PCH is found associated with viral infection or syphilis and usually is chronic Autoantibodies to red blood cells bind to the cells in cold temperatures and fix complement, which can cause intravascular hemolysis upon warming. PCH is caused by biphasic IgG antibody that can bind at low temperature H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 15  Alloimmune Hemolytic Anaemia (AHA) - AHA occurs as the result of Alloantibodies development to an erythrocyte antigen that the individual lacks through transfusion or pregnancy. - Recipient’s lymphocytes recognizes these RBCs are foreign and stimulates antibody production. - The antibody coats the foreign RBCs and shortens RBC survival with positive DAT. - There are two main types: i. Haemolytic transfusion reactions and ii. Haemolytic disease of the fetus and newborn H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 16  Alloimmune Hemolytic Anaemia (AHA) Haemolytic transfusion reactions i. Acute transfusion reaction causing Intravascular hemolysis occurs due to the complete activation of complement mediated by IgM antibodies ii. Delayed transfusion reaction which occur days to weeks after the transfusion. RBCs experience extravascular hemolysis as they are coated with IgG antibodies and removed by the macrophages. Complement is not involved. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 17  Alloimmune Hemolytic Anaemia (AHA) Haemolytic disease of the fetus and newborn (HDN) - Fetus RBCs are destroyed by maternal IgG antibodies crossing thro’ the placenta - The newborn is often with jaundice and anaemia H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 18  Autoimmune Hemolytic Anaemia Drug-Induced AIHA 1. Immune complex mechanism - Drugs binds to plasma proteins and Abs are made against the drugs - Abs made bind to the drug to form an immune complex which adsorbs non-specifically to patient’s RBC, activate complement and cause intravascular haemolysis H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 19 H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 20  Autoimmune Hemolytic Anaemia Drug-Induced AIHA 2. Drug adsorption mechanism - Drugs binds non-specifically to proteins on RBC ; and trigger IgG Abs which bind to the drug and cause extravascular haemolysis 3. Membrane modification mechanism 4. Methyldopa induced mechanism - Drug induces autoantibodies causing extravascular haemolysis H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 21 H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 22 H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 23  Non-immune Hemolytic Anaemia 1. Antagonists in blood or abnormalities in plasma lipids e.g. chemicals 2. Animal venoms e.g. bees , spiders 3. Infectious agents e.g. malarial parasites, babeiosis H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 24  Haemolytic anaemias (HA) Intrinsic HA has 2 main type: 1. Membrane Defects i. Hereditary spherocytosis ii. Hereditary elliptocytosis 2. Enzyme Deficiency Glucose-6-phophate dehydrogenase (G-6-PD) deficiency H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 25  Membrane Defects Defects due to abnormalities in membrane proteins or lipids Defects alter membrane’s stability, shape, deformability and permeability Hemolysis occurs extra-vascularly H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 26  Membrane Defects Skeletal protein abnormalities ◦ Vertical Separating of lipid bilayer from skeletal lattice Result in decrease in surface area-to-volume ratio..spherocyte ◦ Horizontal Disruption of skeletal lattice Membrane destabilizes Cell fragmentation H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 27  Membrane Defects Lipid composition abnormalities ◦ Excess cholesterol accumulates in the outer bilayer of the RBC ◦ Acanthocyte H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 28  Emito.net H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 29  Membrane Defects Hereditary spherocytosis (HS) ◦ Defect in ankyrin & spectrin ◦ Results in the formation of fragile spherocytic red cells. ◦ Spherocyte becomes less flexible and more permeable to Na+ ◦ Tends to affect Northern Europeans ◦ Inherited H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 30  Ilovepathology.com H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 31  Stepwards.com H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 32  Hereditary spherocytosis (HS) CBC Mild anemia MCV is usually normal (77-87f L) MCH normal MCHC is >36% (This is the only condition in which an MCHC can be truly increased.) RDW Increased RBC morphology Spherocyte Varying degrees of polychromasia, anisocytosis and poikilocytosis H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 33  Hereditary spherocytosis (HS) Bone Marrow Normoblastic erythroid hyperplasia Increased iron storage Chemistry Increased Bilirubin Fecal urobilinogen LD/LDH Decreased Haptoglobin Immunohematology DAT negative H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 34  DIAGNOSTIC TESTS FOR HS i. Osmotic fragility - ↑ Cells are incubated in decreasing concentrations of NaCl. Spherocytes lyse sooner than normal red cells. ii. Autohemolysis test Red cells are incubated at 37̊ C for 48 hours. Degree of hemolysis is increased when spherocytes are present. iii. Red cell membrane studies Membrane proteins are analyzed using gel electrophoresis. H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 35  Membrane Defects Hereditary elliptocytosis (HE) A defect of one of the skeletal proteins Results in the formation of fragile elliptocytic red cells that are sensitive to mechanical stress. More permeable to Na+ Increased sensitivity to heat Found commonly in Africa and the Mediterranean H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 36  Hereditary elliptocytosis (HE) Hemolysis not evident Mild Anemia Presence of Elliptocytes or ovalocytes H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 37  Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD) Sex-linked(X) disorder Affects Africans, Middle East, Americas, and Mediterraneans Most common enzyme disorder Denatured hemoglobin precipitates in the RBC after exposure to oxidative stress causing hemolysis H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 38  Hexose monophosphate shunt GSH levels maintained by the conversion of NADPH to NADP NADP is reduced back to NADPH by G6PD MedHealth.Info.com H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 39  Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD) Oxidative stress (reduced GSH)triggers response Unable to generate NADPH to reduce GSH System is overwhelmed Oxidized Hgb accumulates as Heinz bodies H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 40  G6PD Causes of Oxidative Stress Infections – Mechanism not clear – Release of hydrogen peroxide from the WBCs Ingestion of oxidative drugs – Antimalaria drugs (i.e Primaquine) – Quinine, quinidine – Analgesics Ingestion of fava beans – Favism is found in the Mediterranean area Person eats or inhales fava bean or its pollen Hereditary H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 41  Laboratory Findings Decreased H&H (hemoglobin and hematocrit) Hemoglobinuria Increased bilirubin and LD Reticulocytosis Blister cells, bite cells, polychromasia, occasional spherocytes, and fragments Heinz Bodies H.LEE SCI 3009SEF 20/1/2025 Haemolytic Anaemia 42 References A.V.HOFFBRAND & J.E.PETTIT: Essential Haematology. Blackwell Scientific Publications 3rd Edition. LEE Y C Leukemia (AML) 2023 43