IgG subclass deficiency

What is IgG?

IgG or immunoglobulin G is the most common form of antibody, an essential group of proteins in the humoral or circulating immune system.

IgG is composed of 4 peptide chains: 2 heavy chains and two light chains. There are four IgG subclasses.

What is IgG subclass deficiency?

IgG deficiency is an inherited condition in which there is a normal total level of IgG but low levels of at least one of the IgG subclasses. Each of these subclasses has a slightly different immune function:

• IgG-1 forms antibodies against proteins antigens like tetanus
• IgG-2 forms antibodies against antigens like pneumococcal polysaccharides.
• IgG-3 forms antibodies against IgG-1-like antigens
• IgG-4 forms antibodies against extracellular parasites

In patients with IgG subclass deficiency, other components of the immune system function normally.

What causes IgG subclass deficiency?

The inheritance pattern related to IgG subclass deficiency is unknown. IgG subclass deficiency can affect both men and women. Partial gene suppression may prove to be a cause of IgG subclass deficiency (and is a known cause of selective IgA deficiency).

What are the signs and symptoms of IgG subclass deficiency?

Patients with IgG subclass deficiency may have:

• Frequent or chronic infections, especially Streptococcus, Haemophilus, and Branhamella catarrhalis species
• Common diseases like otitis media, sinusitis, pneumonia and bronchitis
• Recurrent episodes of septicemia and meningitis
• Asthma and atopic dermatitis.

How is IgG subclass deficiency diagnosed?

Diagnosis of IgG subclass deficiency is made in a patient with a history of chronic disease. bacterial Infections IgG subclasses can be measured, but the results of this test are not always conclusive. The levels should be retested in several months to determine if the values are really abnormal.

The diagnosis must also take into account the patient's general health, the symptoms that appear and the response to vaccines.

How is IgG subclass deficiency treated?

IgG subclass deficiency is treated with:

• Antibiotics for infection control

• A pneumococcal vaccine to strengthen the immune response against pneumococcal infection.

• IgG therapy, if the most conservative measures are not successful.