Hematology

• What type of cells are dendritic cells?

  Highly phagocytic antigen-presenting cells
• What is the function of dendritic cells?

  Link between innate and adaptive immune systems
• What do dendritic cells express on their surface?

  MHC class II and Fe receptors
• What is the role of eosinophils?

  Defend against helminthic infections
• What type of nucleus do eosinophils have?

  Bilobate nucleus
• What do eosinophils produce?

  Histaminase and major basic protein
• What does eosinophilia stand for?

  Increased eosinophil count
• What are the causes of eosinophilia (PACMAN Eatc)?

  • Parasites
  • Asthma
  • Chronic adrenal insufficiency
  • Myeloproliferative disorders
  • Allergic processes
  • Neoplasia (e.g., Hodgkin lymphoma)
  • Eosinophilic granulomatosis with polyangiitis
• What is the primary function of basophils?

  Mediate allergic reactions
• What do basophils contain in their granules?

  Heparin and histamine
• What is basophilia?

  Increased basophil count
• What do mast cells mediate?

  Local tissue allergic reactions
• From what do mast cells originate?

  Same precursor as basophils
• What activates mast cells?

  Tissue trauma and IgE cross-linking
• What is mastocytosis?

  Proliferation of mast cells
• What are natural killer (NK) cells important for?

  Innate immunity against intracellular pathogens
• What do NK cells contain that aids in their function?

  Cytoplasmic lytic granules
• How do NK cells distinguish between healthy and infected cells?

  By identifying cell surface proteins
• What is the primary function of B cells?

  Mediate humoral immune response
• Where do B cells mature?

  In the bone marrow
• What happens when B cells encounter an antigen?

  They differentiate into plasma and memory cells
• What is the primary function of T cells?

  Mediate cellular immune response
• Where do T cells mature?

  In the thymus
• What is the rule of 8 in relation to T cells?

  MHC II > CD4 = 8; MHC I > CD8 = 8
• What do plasma cells produce?

  Large amounts of specific antibodies
• What is a characteristic feature of plasma cells?

  Clock-face chromatin distribution
• What is hemoglobin electrophoresis used for?

  To analyze different types of hemoglobin
• How does hemoglobin migrate during electrophoresis?

  From cathode to anode
• What is the direct antiglobulin test used for?

  To detect antibodies against RBCs
• What does the indirect antiglobulin test assess?

  Presence of anti-RBC antibodies in serum
• What is the role of aspirin in hemostasis?

  Inhibits TXA₂ synthesis
• What do clopidogrel and prasugrel inhibit?

  ADP-induced expression of GPIIb/IIIa
• What does ristocetin activate?

  vWF to bind GpIb
• What is the process of platelet plug formation?

  1. Platelet adhesion to injury site
  2. Activation and degranulation of platelets
  3. Formation of a temporary platelet plug
  4. Recruitment of additional platelets
  5. Stabilization of the plug by fibrin mesh
• What does desmopressin promote?

  Release of vWF and factor VIII
• What does vWF do?

  Carries and protects factor VIII