September 29, 2015 - B-Cell Defects Flashcards Preview

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Flashcards in September 29, 2015 - B-Cell Defects Deck (11):

Humoral Immune Deficiency Presentation

Recurrent sinopulmonary infections such as sinusitis, otitis media (ear infection), and pneumonia.

These often present after 6 months of age when maternal Ab titers wane.


Otitis Media

Ear infection.


Causes of Humoral Immunodeficiency

1. Abnormal B cell maturation resulting in low (or no) B cell numbers. No B cells, no antibody.

2. A defect in the Ab making ability of the B cells. B cells are present, but they can't make antibodies.

3. A defect in the ability of B cells to respond to antigen, resulting in abnormal antibody production. B cells can make antibody, but can't get the signal to do it.



Abnormal B cell maturation. Absent B cells.

85% due to X-linked agammaglobulinemia (XLA or Bruton agammaglobulinemia).



Low IgG, IgA, or IgM (not none)


Clinical Presentation of Agammaglobulinemia

Recurrent sinopulmonary infections

Infection with encapsulated organisms

May present with neutropenia

No lymph tissue


Auto-Immune Disease and B-Cell Defects

If B cells are present, but can't make the proper antibody, the risk for AI diseases goes up.

Most common are autoimmune cytopenias.


Common Variable Immune Deficiency (CVID)

Decreased level of at least two Ig isotypes, usually IgG and IgA.

Impaired specific Ab production leads to poor vaccine response.

1/50,000 Caucasians


IgA Deficiency

The most common form of deficiency. 

Increased susceptibility to sinopulmonary infections, though most are asymptomatic.


IgA Deficiency and IVIG

May develop anaphalaxis. Do not administer.

Except in real life where it doesn't really matter.


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