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.