Agammaglobulinemia

Alternative names

Bruton's agammaglobulinemia; X-linked agammaglobulinemia

Definition

Agammaglobulinemia is an inherited disorder characterized by very low levels of protective immunoglobulins; affected people develop repeated infections.

Causes, incidence, and risk factors

Agammaglobulinemia is rare disorder that primarily affects males, because it is inherited as an X-linked recessive trait (like hemophilia). It is the result of a genetic abnormality that blocks the development of normal, mature B-lymphocyte cells. As a consequence, the body produces very little (if any) gamma globulin (IgG) and other immunoglobulins in the bloodstream. Immunoglobulins are molecules that play a significant role in the immune response, which protects against illness and infection.

In the absence of protective immunoglobulins, affected individuals develop repeated infections. People with this disorder are particularly susceptible to bacterial infections caused by Hemophilus influenzae, pneumococcus (Streptococcus pneumoniae), and staphylococci as well as repeated viral infections. The upper respiratory tract, lungs, and skin are common sites of infection.

Symptoms

• family history of agammaglobulinemia (or other immune disorder)
  
• frequent infections, may begin early or have delayed onset.
  

Frequent episodes of:

• sinusitis
  
• conjunctivitis
  
• pneumonia
  
• bronchitis
  
• skin infections
  
• chronic diarrhea
  

Note: Frequent infection may begin early or later in life.

Signs and tests

The disorder is confirmed by laboratory measurement of serum immunoglobulins. Tests include:

• immunoelectrophoresis - serum
  
• quantitative immunoglobulins (nephelometry)
  
• IgG usually less than 200 mg/dL (milligrams per deciliter of serum)
  
• IgA and IgM almost unmeasurable
  

Treatment
The goal of treatment is to reduce the number and severity of infections as well as provide genetic counseling to affected families.

Intramuscular or intravenous injections of immune serum globulin (gamma globulin, IVIg) help to boost the immune system. Infusions of blood plasma into a vein gives a quick supplement to the immune system (plasma contains antibodies, including IgG, IgM, and IgA). High doses of high titer gamma globulin are needed for severe infections.