Immunology and Allergies Practice Questions

Q: Which of the following is NOT typically seen in Systemic Juvenile Idiopathic Arthritis?

Rheumatoid Factor positive. **Explanation:** Systemic Juvenile Idiopathic Arthritis (sJIA), also known as **Still’s Disease**, is distinct from other forms of JIA because it is primarily an **autoinflammatory** rather than a classic autoimmune disease. 1. **Why Option A is correct:** In sJIA, the diagnosis is clinical and based on systemic features. **Rheumatoid Factor (RF)** is characteristically **negative**. If a child is RF positive, they are classified under "Polyarticular JIA (RF positive)," which has a different clinical course and genetic association (HLA-DR4). sJIA is driven by innate immunity (IL-1 and IL-6) rather than the adaptive autoantibody-driven pathways seen in RF-positive cases. 2. **Why the other options are incorrect:** * **High fever with rash (C):** This is the hallmark of sJIA. The fever is typically "quotidian" (spiking once daily, usually in the evening) and is accompanied by a **salmon-pink, evanescent (fleeting) maculopapular rash** that appears during the fever peak. * **Hepatosplenomegaly (B):** Systemic involvement is common, including lymphadenopathy and hepatosplenomegaly, reflecting the generalized inflammatory nature of the disease. * **Elevated ESR (D):** Laboratory findings in sJIA show intense systemic inflammation, including marked leukocytosis, thrombocytosis, and significantly elevated ESR and C-reactive protein (CRP). **NEET-PG High-Yield Pearls:** * **Ferritin:** Extremely high levels are a marker for sJIA and can signal the onset of **Macrophage Activation Syndrome (MAS)**, a life-threatening complication. * **Uveitis:** Unlike Oligoarticular JIA, uveitis is **rare** in the systemic subtype. * **Treatment:** IL-1 inhibitors (Anakinra, Canakinumab) and IL-6 inhibitors (Tocilizumab) are highly effective.

Q: All of the following are true regarding Hyper IgE syndrome EXCEPT:

High IgE with low IgG, IgA, and IgM.. **Explanation:** **Hyper IgE Syndrome (HIES)**, also known as **Job Syndrome**, is a rare primary immunodeficiency characterized by the triad of elevated serum IgE, recurrent "cold" staphylococcal abscesses, and pneumonia with pneumatocele formation. **Why Option D is the Correct Answer (The "Except"):** In Hyper IgE Syndrome, while serum **IgE levels are characteristically very high** (often >2000 IU/mL), the levels of other immunoglobulins like **IgG, IgA, and IgM are typically normal**. The defect is not a generalized failure of antibody production but rather a signaling defect (most commonly a **STAT3 mutation**) that impairs Th17 cell differentiation, leading to dysregulated immune responses. **Analysis of Other Options:** * **Option A:** Most cases (Type 1 HIES) follow an **Autosomal Dominant** inheritance pattern due to mutations in the *STAT3* gene. It exhibits variable expressivity, meaning the severity of symptoms differs among affected individuals. * **Option B:** Patients develop distinct **coarse facial features** over time, including a prominent forehead, deep-set eyes, a broad nasal bridge, and a wide fleshy nose. * **Option C:** Recurrent **Staphylococcal infections** are a hallmark. These are often termed **"Cold Abscesses"** because they lack the classic signs of inflammation (redness, warmth) due to impaired neutrophil recruitment. **NEET-PG High-Yield Pearls:** * **Genetic Defect:** Most common is **STAT3 mutation** (AD); a rarer AR form involves *DOCK8* mutation. * **Clinical Mnemonic (FATED):** **F**acies (coarse), **A**bscesses (cold), **T**eeth (retained primary teeth), **E**levated IgE, **D**ermatological (eczema). * **Skeletal Findings:** Scoliosis and hyperextensibility of joints are frequently associated. * **Pathophysiology:** Failure of Th17 cells leads to a lack of IL-17, which is crucial for recruiting neutrophils to fight fungal and bacterial infections.

Question 1

A 20-year-old male presented with eczema, recurrent skin abscesses, and recurrent lung infections. There is eosinophilia and high serum levels of IgE. What is the most likely diagnosis?

Accepted Answer

Job's syndrome

Answer

Shwachman's disease

Answer

Wiskott-Aldrich syndrome

Answer

Nezelof syndrome

Question 2

A 9-year-old boy presented with high fever, pruritic erythematous rash, joint pain, and lymph node enlargement. He had a history of upper respiratory tract infection for which he was on cefaclor for 7 days, completing a 10-day course. What is the most likely diagnosis?

Accepted Answer

Serum sickness-like illness

Answer

Hemolytic-uremic syndrome

Answer

Kawasaki disease

Answer

Type III hypersensitivity

Question 3

A child with an obvious rash presents with recurrent infections. Investigations revealed a decreased platelet count and reduced IgM. Which of the following is the most likely diagnosis?

Accepted Answer

Wiskott-Aldrich Syndrome

Answer

Idiopathic Thrombocytopenic Purpura

Answer

Thrombotic Thrombocytopenic Purpura

Answer

DiGeorge anomaly

Question 4

Which of the following conditions is characterized by immunoglobulin deficiency?

Accepted Answer

All of the above

Answer

Wiskott Aldrich syndrome

Answer

X linked hypogammaglobulinemia

Answer

Kawasaki disease

Question 5

Which of the following is NOT typically seen in Systemic Juvenile Idiopathic Arthritis?

Accepted Answer

Rheumatoid Factor positive

Answer

Hepatosplenomegaly

Answer

High fever with rash

Answer

Elevated Erythrocyte Sedimentation Rate

Question 6

A 3-year-old child presents with recurrent pneumonia, eczema, and thrombocytopenia. Which protein synthesis is abnormal in this child?

Accepted Answer

Wiskott-Aldrich syndrome protein (WASp)

Answer

Hamartin

Answer

Adenosine deaminase

Answer

HLA-A1

Question 7

All of the following are true regarding Hyper IgE syndrome EXCEPT:

Accepted Answer

High IgE with low IgG, IgA, and IgM.

Answer

Inheritance is as a single locus autosomal dominant trait with variable expression.

Answer

Coarse facial features.

Answer

Recurrent staphylococcus abscesses involving skin and lungs.

Question 8

A two-year-old male child completed an 8-day course of cefaclor. He then developed low-grade fever, malaise, lymphadenopathy, irritability, and a generalized erythematous rash that is mildly pruritic. What is the most probable diagnosis?

Accepted Answer

Type 3 hypersensitivity

Answer

Kawasaki disease

Answer

Partially treated meningitis

Answer

IMN

Question 9

A 9-year-old male child presented with a history of spiking fevers from the last 2 months, which have been as high as 104°F. On examination, he has spindle-shaped swelling of multiple finger joints and complains of upper sternal pain. When he had fever, his mother noticed a salmon-colored rash that resolves with the resolution of the fever. He had no conjunctivitis or any oral ulcers, but his heart sounds are muffled and he has pulsus paradoxus. Which of the following is the most likely diagnosis?

Accepted Answer

Juvenile idiopathic arthritis

Answer

Toxic synovitis

Answer

Rheumatic fever

Answer

Septic arthritis

Question 10

A 10-year-old boy receives an injection of pollen extract. Shortly after, he develops nausea, a strange feeling in his chest, facial flushing, and a muffled, strained voice. What is the immediate priority in managing this patient's suspected anaphylaxis?

Accepted Answer

Prepare for endotracheal intubation

Answer

Administer intramuscular diphenhydramine

Answer

Administer oxygen

Answer

Administer subcutaneous epinephrine 1:1000

Immunology and Allergies — MCQs

Immunology and Allergies — MCQs

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