Immunodeficiency- L14

Question 1

Most common immunodeficiency

Answer 1

IgA deficiency. Humoral (B cell) is the most common group of deficiencies.

Question 2

SCID

Answer 2

• Severe combined immunodeficiency
• Oral thrush is common
• X linked and autosomal recessive
• Only cure is bone marrow transplant
• Common IL-2 gamma chain defect
• Adenosine deaminase (ADA) deficiency
• Purine nucleotide phosphorylase deficiency
• T cell transduction defects
• Loss of interleukin signaling
• No T cells or B cells

Question 3

Humoral immunodeficiency

Answer 3

• B cell enumeration (CD19 and/or CD20)
• Quantitative immunoglobulins
• NEVER give live attenuated vaccines!!!

Question 4

X-linked Agammaglobulinemia

Answer 4

• Humoral immunodeficiency
• Absence of B cells due to mutation in Bruton’s tyrosine kinase (essential for B cell signaling)
• CD40 ligand deficiency
• Hypogammaglobulinemia with hyper IgM
• Selective defect in anti-polysaccharide antibody production
• CD40 deficiency also interferes with signaling with macrophages–opportunistic infections
• Susceptible to encapsulated bacteria, chronic enterovirus meningoencephalitis
• Lifelong lymphoma risk

Question 5

Selective IgA deficiency

Answer 5

• 2/3 asymptomatic
• Can be associated with IgG subclass 2 deficiency
• Recurrent sinopulmonary infections
• Defect in producing antibodies to polysaccharide agents

Question 6

Complement deficiency

Answer 6

-Susceptible to neisseria, particularly meningitidis

Question 7

Phagocyte deficiency

Answer 7

• Chronic granulomatous disease
• Highest risk for infection is catalase positive bacteria
• Frequent fungal infections

Question 8

DiGeorge syndrome

Answer 8

• Cellular immunodeficiency
• Abnormal embryonic development of 3rd and 4th pharygeal pouches
• Hypoplasia or aplasia of thymus
• Little or no T cells
• Hypoparathyroidism
• 22q11.2 deletion
• Viral and fungal infections