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.

The regular immunoglobulin replacement can support the antibiotic treatment that is often necessary and prevent severe, recurrent infections. In addition, it helps to maintain vitally important functions of the organs.

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

CVID in adults

Clinical symptoms of CVID may also become noticeable at the age between 20 and 30 years. For many years, infections can be managed more or less without severe problems. But because of the long-lasting IgG deficiency, these patients develop severe chronic infections and organ dysfunctions affecting lungs, stomach, liver, spleen and lymph nodes. The IgG deficiency is associated with IgM and IgA deficiency.

Mostly, the disorder is only recognized after a considerable delay, or even not at all. The main reason for this is an inadequate knowledge of this condition.

Secondary antibody deficiencies can occur when the capability of immune cells to react to pathogens and to form antibodies is disturbed due to illness. This form of antibody deficiency is found, for example, in conjunction with a tumor or an autoimmune disease, when the primary disease itself, or the immunosuppressant therapy necessary, permanently impairs the function of the immune system.

Here, too, the causes are usually at cellular level and affect the multiplication and maturation of immune cells or the interaction between different cells. As antibody deficiency is not life-threatening in these cases, or may occur for a limited time, immunoglobulin preparations are administered only 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.