Immunology

Question 1

Ataxia
Telangiectasias
Sinopulomonary Infections (IgA deficiency)

Defect in DNA repair enzymes

Answer 1

Ataxia-telangiectasia

Question 2

Occulocutaneous albinism
Pyogenic infections
Progressive neurological dysfunction

Answer 2

Chediak-Higashi Syndrome, LYST gene

Question 3

Severe bacterial & fungal infections
Granuloma formation

By deficiency of NADPH oxidase => susceptibility to catalase +ve organisms (S. aureus, E. coli, Aspergillus, Klebsiella, Candida)

Answer 3

Chronic granulomatous disease

Question 4

Congenital heart disease (Conotruncal abnormalities)
Dysmorphic facies
Hypocalcemia
Absent thymus

22q11 deletion

Answer 4

DiGeorge Syndrome

Failure of development of 3rd & 4th pharyngeal pouches

Question 5

Severe bacterial & viral infections in infancy
Chronic diarrhea
Mucocutaneous candidiasis
Thymic hypo/aplasia
Absence of germinal centers & B cells
Failure to thrive

Absent CD3 +ve T cells
Hypogammaglobulinaemia

Answer 5

Severe combined immunodeficiency (SCID)

Question 6

Recurrent Neisseria infection

Answer 6

C5-C9 Deficiency

Question 7

Recurrent infections, worsening with age
Thrombocytopenia
Eczema

Answer 7

Wiskott-Aldrich

Question 8

Insufficient production of mature B cells

Recurrent infection by encapsulated bacteria

Answer 8

X-linked (Bruton’s) agammaglobulinaemia

Question 9

coarse Facies
cold (noninflamed) staphylococcal Abscesses
retained primary Teeth
elevated IgE
Dermatologic problems (eczema)

Th1 cells fail to produce IFN-y => inability of neutrophils to respond to chemotactic stimuli

Answer 9

Hyper IgE (Job’s) Syndrome

Question 10

Recurrent bacterial infections
absent pus formation
Delayed separation of umbilical cord

Defect in LFA-1 integrin (CD18) protein on phagocytes => cannot leave blood vessels.

Neutrophilia

Answer 10

Leukocyte adhesion deficiency (type I)

Question 11

Hyperacute transplant rejection - Give:

1) Onset
2) Pathogenesis
3) Features

Answer 11

1) Within minutes
2) preformed recipient Abs to donor tissue (type II)
3) Occlusion of graft vessels => ischaemia & necrosis

Question 12

Acute transplant rejection - Give:

1) Onset
2) Pathogenesis
3) Features

Answer 12

1) Weeks after
2) Recipient CTLs against donor MHC. Reversible with immunosuppressants (cyclosporine, muromonab-CD3)
3) Vasculitis of graft vessels - dense lymphocytic infiltrate

Question 13

Chronic transplant rejection - Give:

1) Onset
2) Pathogenesis
3) Features

Answer 13

1) Months to years
2) Non-self Class I MHC perceived by recipient CTLs as class I self MHC presenting as a non-self antigen.
3) Irreversible. T-cell & Ab-mediated obliterative vascular fibrosis and fibrosis of tissue

Question 14

Graft-versus-host transplant rejection - Give:

1) Onset
2) Pathogenesis
3) Features

Answer 14

1) Varies
2) Immunocompetent T cells from graft proliferate in immunocompromised host => severe host organ dysfunction
3) Maculopapular rash, jaundice, hepatosplenomegaly, diarrhea. Usually in BM & liver transplants