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Introduction to antibody deficiency

An antibody deficiency is a manifestation of the disturbed maturation or function of lymphocytes. The cells react inadequately, if at all, to invading pathogens, and the immune system is incapable of maintaining a normal concentration of antibodies in the blood.

The consequence is frequently recurring and sometimes life-threatening infections, as well as disturbance of the function of organs. A typical consequence in particular is an increased susceptibility to bacterial infections. Wound healing and tissue regeneration can be impaired because inflammatory reactions are not regulated.

A distinction is made between congenital (primary) and acquired (secondary) antibody deficiency diseases.
 

Primary antibody deficiency (PAD)

There are several causes of primary antibody deficiency diseases, such as:

  • B cell deficiency (antibody producing cells); they may be absent, or present but  not working correctly
     
  • disturbance of the interaction between the various cells of the immune system
     
  • metabolic disorders
     
  • genetic defects

To date, around 100 different congenital immune defects have been identified. Their prevalence is estimated at 1 per 10,000 inhabitants.

As the patients affected either produce too few antibodies (hypogammaglobulinaemia) or no antibodies of their own at all (agammaglobulinaemia), they must be treated life-long with immunoglobulin preparations.

Primary antibody deficiency not only manifests as an increased tendency to infection, but, if left untreated, may lead to other conditions such as lung disease, an increased risk of autoimmune diseases or tumors.

Many, primary antibody deficiencies are diagnosed in childhood. Such PID patients have more severe bacterial and viral infections than other children. Specific warning signs may help to increase the awareness to detect PID in children and adults.

Regular immunoglobulin replacement is often necessary to prevent severe, recurrent infections in addition to antibiotic treatment.

Intravenously administered immunoglobulin preparations (IVIG) have proved their effective­ness for many years in raising the serum IgG concentration. The dose has to be adjusted individually as the antibody deficiency can vary widely in its severity. Dosages of immunoglo­bulins between 0.2 and 0.8 grams per kilogram bodyweight are recommended, every three to four weeks.

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Warning signs PID
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CVID in adults

Common variable immune deficiency (CVID) may also be diagnosed later in life between the ages of 20 and 40 years. In many cases infections can be managed without severe complications. However, over time these patients may go on develop severe chronic infections and organ damage affecting the lungs, stomach, liver, spleen and lymph nodes. The IgG deficiency may be associated with IgM and IgA deficiency.

There is frequently a long delay in diagnosing PAD, or sometimes not at all. There are several reasons for this delay such as inadequate knowledge of this condition in primary care, failure to link several symptoms (e.g. infections).

The long way to the right diagnosis - a patient history

The movie describes the long way of a young woman until CVID was diagnosed.  The frequency of coughing episodes, bronchitis and middle ear infections increased gradually..

Secondary antibody deficiencies

Secondary antibody deficiencies can be caused by several things: firstly, as a result of illness such as leukaemia or other malignancy.  Secondly it can be a as result of medication most notably drugs given to suppress the immune system for example after an organ or bone marrow transplant or when a patient is being treated for an autoimmune disease.  It may be permanent of transient.

Here, too, the causes are usually at cellular level and affect the multiplication and maturation of B-cells or the interaction between different cells of the immune system. As in primary antibody deficiency immunoglobulin preparations are administered for the prevention (prophylaxis) of infections in patients with an increased tendency to infection. The recommended immunoglobulin dose is 0.2 to 0.4 grams per kilogram bodyweight every three to four weeks.