30 Questions
What mechanism is responsible for the diffuse white plaques in the oral cavity of the 1-month-old male?
Decreased B lymphocyte activity
In a 8-month-old with super high IgM levels on a lab report, what mechanism is likely involved?
Deficiency of CD40 receptor on B cells
What is the likely diagnosis for a 6-year-old female with recurrent Staph abscesses, eczematoid skin lesions, and abnormal dentition?
Hyper IgE syndrome (Job syndrome)
What cell dysfunction is responsible for eczematoid skin lesions and thrombocytopenia in a 12-month-old male with history of infections?
T cell
In a 3-year-old female with dilated superficial blood vessels on the face and a wobbly gait, what mechanism is likely at play?
Failure of double-stranded DNA break repair
What is the likely diagnosis for a 17-month-old male presenting with lymphadenopathy, fever, hepatosplenomegaly, low RBCs and WBCs, and high IgM and IgG levels?
Common variable immunodeficiency (CVID)
What is a common drug associated with agranulocytosis, often indicated by mouth ulcers, sore throat, and fever?
Ganciclovir
In which type of hypersensitivity reaction does cryoglobulinemia play a role, causing skin lesions, Raynaud phenomenon, muscle pain, and glomerulonephritis?
Type III
In hyper-IgM syndrome, what biological property is associated with the predominant immunoglobulin in the serum of affected patients?
Complement activation
Which of the following is NOT a common symptom associated with cryoglobulinemia?
Joint swelling
What is the mechanism of action of thionamides in causing neutropenia?
Inhibition of DNA synthesis
Which patient characteristic is associated with hyper-IgM syndrome?
Defective CD40 ligand expression on B cells
What is the mechanism by which lipid A of lipopolysaccharide (LPS) in gram (-) sepsis stimulates macrophages?
Interacting with toll-like receptor 4 (CD14 co-receptor)
Which cytokine is responsible for causing fever in response to lipopolysaccharide (LPS) exposure?
IL-1
What is the role of toll-like receptor 4 (CD14 co-receptor) in the immune response to endotoxin exposure?
Stimulating cytokine release
In a patient presenting with toxic shock syndrome, which immunological receptors are primarily involved?
MHC II and TCR
How can a patient with phenylketonuria (PKU) be identified shortly after birth to prevent complications?
Routine heel-prick test for newborn screening
What is the key enzyme deficiency in phenylketonuria (PKU) that leads to the need for dietary restrictions?
Phenylalanine hydroxylase
What is the mechanism behind the development of Hemolytic disease of the newborn (Rh type)?
Fetal blood containing Rh antigen crosses the placenta and sensitizes the mother's immune system to produce anti-Rh antibodies.
Which antibody type is predominantly present in individuals with opposing blood types, except for those with O blood?
IgM antibodies
Which infectious association is commonly linked to a positive Coombs test due to IgM antibodies against RBCs?
Cytomegalovirus (CMV)
How does molecular mimicry contribute to the pathogenesis of some autoimmune diseases?
It leads to the generation of autoantibodies due to similarities between foreign and self-antigens.
Which antibody is involved in the hemolysis of fetal Rh(+) RBCs in Hemolytic disease of the newborn (Rh type)?
IgG
Why can a fetus be symptomatic if a mother with O blood has a higher percentage of anti-A and -B antibodies that are IgG?
The elevated IgG antibodies cause hemolysis of fetal RBCs.
What is the effect of p53 mutation in cancer invasion?
Defective DNA repair
In a patient with cellulitis who develops fever, confusion, tachycardia, and low blood pressure, which two cytokines are likely responsible for the condition?
IL-1 and TNF-a
Why would giving aspirin or ibuprofen decrease fever in a patient with sepsis?
Inhibiting IL-1 production
What is responsible for the loss of appetite in a patient with breast cancer who has lost 20 lbs in the past month?
TNF-a-induced cachexia
In a study comparing two cell lines, one with an IL-2 gene transfected and the other without, which type of cell is likely generating a stronger immune response?
T lymphocyte
If a USMLE question focuses on sepsis and asks about the molecule responsible for changes in blood pressure, what would be the most likely correct answer?
TNF-a
Test your knowledge on the relationship between lipopolysaccharide (LPS) and cytokine production. Understand the effects of lipid A of LPS on macrophages, and the roles of IL-1 and TNFalpha in fever, vascular permeability, and low blood pressure.
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