Lymphoid Structures
Primary lymphoid organ where T-cells mature, located in the anterosuperior mediastinum
What is the thymus?
(arises from 3rd pharyngeal pouch)
Enzyme responsible for the initiation of the respiratory burst in phagocytes
What is NADPH oxidase complex?
Photo A
What is CMV?
These three cytokines secreted from macrophages are most famous for causing fever and sepsis
What are IL-1, IL-6, and TNF-alpha?
This type of hypersensitivity reaction is characterized by preformed antibodies that bind to cell-surface antigens, causing cellular inflammation, destruction, or dysfunction
What is a type II hypersensitivity reaction?
Secondary lymphoid organ that contains a follicle, medulla, and paracortex
What is a lymph node?
Immunoglobulins responsible for activating complement
What are IgM and IgG?
Fc portions of Ig bind to fix complement
GM makes classic cars
Photo B
What is dermatomyositis?
These cytokines are notorious for the development and maintenance of granulomas in tuberculosis infection
What are IL-12 and TNF-alpha?
This type of hypersensitivity reaction can be associated with vasculitis
You have a patient with ptosis, diplopia, proximal muscle weakness, and an anterior mediastinal mass on chest x-ray. Underlying neoplasm?
What is a thymoma?
Can also cause pure red cell aplasia or Good syndrome
Absence of these molecules can activate natural killer cells to release cytotoxic granules
What are MHC class I molecules?
Photo C
What is AML?
Clue: Auer rods
This interferon activates macrophages, increases MHC expression/antigen presentation by all cells, and is secreted by Th1 cells
What is IFN-gamma?
A 35-year-old man undergoes a heart transplant. Two weeks later, he develops dyspnea and fatigue. Echocardiography shows decreased left ventricular function. Endomyocardial biopsy reveals dense interstitial lymphocytic infiltration with focal areas of myocyte damage. Which best describes the mechanism of this rejection?
A) Direct activation of recipient CD8+ T cells against donor MHC molecules
B) Preformed anti-donor antibodies causing complement-mediated injury
C) Accumulation of CD4+ T cells and macrophages leading to fibrosis
D) Deposition of immune complexes within the graft vasculature
What is A?
Type IV hypersensitivity
A young boy presents to your clinic with his mother due to recurrent infections. He has hypertelorism, cleft palate, and a harsh systolic murmur heard best at the left upper sternal border. Lab studies reveal hypocalcemia. What is the underlying cause?
A. Defective migration of neural crest cells
B. Trinucleotide repeat expansion
C. Defective DNA mismatch repair
D. Abnormal collagen synthesis
What is A?
DiGeorge Syndrome (22q11.2 deletion syndrome)
What is A?
Photo D
What is Peutz-Jeghers syndrome?
This interleukin receptor is blocked by the monoclonal antibody, Basiliximab
What is IL-2?
A 35-year-old woman presents with progressive fatigue and yellowing of the eyes. Laboratory findings reveal hemoglobin of 8.2 g/dL, elevated indirect bilirubin, and positive direct Coombs test. Peripheral smear shows spherocytes.
Which of the following best describes the underlying pathophysiology?
A) Immune complex deposition in small blood vessels
B) T-cell-mediated destruction of erythrocytes
C) Antibody-mediated destruction of erythrocytes
D) IgE-mediated mast cell degranulation
E) Delayed-type hypersensitivity reaction
What is C?
Type II hypersensitivity rxn, AIHA
This region is composed primarily of CD4+ T cells in the spleen -- view image on PP slide
What is the periarteriolar lymphatic sheath?
A young man presents to your clinic to establish care. He has a history of ulcerative colitis, arthritis, and ankylosing spondylitis. The HLA allele associated with this disease process encodes for a surface protein with which of the following properties?
A. Two polypeptide chains of equal length
B. Lipid anchor, oligosaccharide core, and O-antigen
C. Two polypeptide chains of different length
D. A transmembrane heterodimer comprised of one alpha and one beta chain
What is C?
HLA-B27 is associated with IBD-associated arthritis and ankylosing spondylitis. HLA-B is a MHC-class I molecule that has two polypeptide chains that are different lengths.
Photo E
What is cutaneous T-cell lymphoma (mycosis fungoides)?
Your newborn patient has delayed separation of the umbilical cord. It is determined that your patient has an autosomal recessive disorder caused by a defect in an immune cell adhesion protein. What is the protein?
What is CD18 (LFA-1 integrin)?
A 19-year-old woman with a history of asthma presents with acute shortness of breath after exposure to cat dander. Physical examination reveals bilateral expiratory wheezing. She is given albuterol and corticosteroids with improvement in symptoms.
Which cytokine is most responsible for promoting the IgE production involved in this reaction?
A) IL-1
B) IL-4
C) IL-6
D) IFN-γ
E) TGF-β
What is B?
IL-4 stimulates production of IgE