A Case of X-linked Agammaglobulinemia

Case Presentation


Billy DeWitt was a normal, full-term baby at birth. Beginning at
about 10 months of age, Billy suffered from a series of infectious
processes such as sinusitis, otitis media, and pneumonia. All of these
conditions were successfully treated with antibiotics, but within a few
weeks of the resolution of one infection, another would occur.

Now at about four years of age, Billy is examined by a pediatrician
who notes that Billy lacks palatine tonsils, although he does not have a
history of tonsillectomy. Questioning of Billy’s mother reveals that
she had two male relatives who died in infancy from infectious disease.
The physician orders laboratory tests that reveal that the quantity of
immunoglobulin in Billy’s serum is about one-fifth of normal, and that
there is a marked deficiency in the number of circulating B-lymphocytes
in Billy’s blood. Tests to determine the functional state of Billy’s
T-lymphocytes are all normal.

Billy is diagnosed as having a genetic disorder called X-linked
Agammaglobulinema. He begins a course of monthly intravenous injections
of gamma globulin which he will need to continue for the rest of his
life. Billy should no longer suffer recurrent infections and should
develop physically and mentally as a normal child. Aside from receiving
monthly injections of gamma globulin, he should lead a normal life now
that this course of treatment is in place.

Questions

1. What are the differences between nonspecific and specific (immunity)
   body defenses?
   
2. In what tissue do B- and T-lymphocytes originate and what are the
   two steps involved in lymphocyte “maturation”?
   
3. Describe the two “arms” of immunity.
   
4. Define the term antigen and state which class of organic
   molecules make the best antigens, and why.
   
5. What are the five classes of antibody?
   
6. What are the means by which antibody molecules exert a protective
   effect?
   
7. What are the basic differences between active and passive
   immunity?
   
8. Billy was free of infections for the first few months of life. Why?
   
9. Why did Billy lack tonsils?
   
10. Explain X-linked inheritance, and name other genetic diseases that
    are known to be X-linked.
    

chose a question and answer it

Q.8 because of the effect of maternal antibodies