Type II Hypersensitivity

Question 1

What type of hypersensitivity is a Type II reaction?

Answer 1

Cytotoxic

Question 2

What is a Type II reaction induced by?

Answer 2

The antigen on the target cell binds directly with IgG and IgM resulting in cellular destruction or function reduction

Question 3

Complement-mediated lysis definition

Answer 3

Antigen attacks target cell and the antibody reacts with the antigen present on the cell surface and activates the complement system resulting in direct membrane damage

Question 4

Complement-mediated lysis example

Answer 4

ABO mismatch from a blood transfusion, RBCs destroyed by autoimmune hemolytic anemia

Question 5

Macrophage-mediated phagocytosis definition

Answer 5

Cell destruction by macrophages once IgG and C3 opsonize the target cell

Question 6

Macrophage-mediated phagocytosis example

Answer 6

Erythroblastosis fetalis (hemolytic anemia of the newborn)

Question 7

Patho for hemolytic anemia of the newborn

Answer 7

Mom is Rh-, dad and baby are Rh+

During a first pregnancy where the baby is Rh+, the baby’s RBCs leak into the mother’s circulation during delivery

Postpartum, the mother’s body will recognize the Rh+ RBCs from the baby and make B cells that will activate and become sensitized -> plasma cells mount and specific IgG Abs will be produced against the child’s Rh+ RBCs

In future pregnancies where the baby is Rh+, the mother will mount anti-Rh- immunoglobulins quicker -> enter placenta -> cause lysis of the infant’s RBCs

Question 8

Hemolytic anemia of the newborn treatment

Answer 8

Rho-Gam

Question 9

What do you have to do before administering Rho-Gam?

Answer 9

Verify that the mother is Rh-!

Question 10

Rho-Gam MoA

Answer 10

Administer it to Rh- mothers to suppress their antibody response to fetal Rh+ RBCs