Pathologies

Question 1

X-linked agammaglobulinemia (XLA)

Answer 1

No circulating antibodies
B-cell development is arrested at the pre B-cell stage
Lack of a signal transduction molecule essential for B-cell maturation
Patients suffer recurrent infections from extracellular bacteria
Patients must be treated with antibiotics and immunoglobulin from pooled blood

Question 2

Chronic lymphocytic leukemia (CLL)

Answer 2

-B1 cells are often the source for B-cell tumors (bc of self renewal)
Risk factors long term exposure to: Pesticides, chemical fertilizers, Smoking, Heavy metals, Medical radiation
-Lymphocytes are larger and have a lot of lymphocytes in one field
-Smudge cells

Question 3

Granuloma Formation

Answer 3

Interferon gamma (IFNγ) and CD40 ligand from Th1 cells are required for Mac activation
If both signals aren’t given, the Macrophages do not become highly microbicidal…
Granuloma formation, such as with M. tuberculosis infections

Question 4

Leprosy

Answer 4

TH1 response -Tubercoloid Leprosy:
-Activation of infected macrophages and control of bacterial growth. Patients usually survive with chronic disease.
TH2 response - Lepromatus Leprosy:
-Uncontrolled bacterial growth within MQ due to lack of MQ activation Bacilli disseminate widely and the outcome is usually fatal.

Question 5

C3 deficiency

Answer 5

-Recurrent gram-negative bacterial infections

Question 6

Deficiencies of C5, C6, C7, C8, C9

Answer 6

-Lack of complement-mediated lysis

Neisseria sp. infections

Question 7

Hyper IgM deficiency

Answer 7

• No isotype switching or somatic hypermutation in B cells

- Extracellular bacterial/fungal infections

Question 8

Omenn Syndrome

Answer 8

-Impaired V/D/J recombination, Mutations in the RAG genes
-All infections
Skin reddening
Scaly skin rash
Chronic diarrhea
Failure to thrive
Lymphedema
Hepatosplenomegaly

Question 9

Burkitt’s lymphoma (FAB L3)

Answer 9

• As B-cells rearrange immunoglobulin genes, Ig gene joined to a gene involved with control of cellular growth
• MYC proto-oncogene on chromosome 8 is joined by translocation to immunogloblin heavy-chain gene on chromosome 14
• Can also be joined to a kappa light chain gene on chromosome 2 or
• Can be joined to a lambda light chain gene on chromosome 22
• Typical of many B-cell tumors

Question 10

Multiple Myeloma (Plasma Cell Myeloma)

Answer 10

-Loss of control of the proliferation of B cells and antibody production
Chromosomal translocation between Ig heavy chain genes and an oncogene
-Believed to be the initiating event leading to a proliferation of a plasma cell clone and genomic instability
-This instability leads to additional mutations and translocations
-lots of plasma cells in slide