An antibody deficiency is always a manifestation of the disturbed maturation or function of lymphocytes in the blood. The cells only 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 down-regulated.
A distinction is made between congenital (primary) and acquired (secondary) antibody deficiency diseases.
Primary antibody deficiency
Among the causes of primary antibody deficiency diseases are congenital functional disorders of the antibody-producing B cells and also disturbance of the interaction between the various immune cells, metabolic disorders and genetic defects.
To date, around 100 different congenital immune defects have been identified. Their incidence 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 diseases are not only manifested in an increased tendency to infection, but, if left untreated, they also lead to an increased risk of the development of autoimmune diseases or tumors.
Mostly, primary antibody deficiency is 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.