Antibodies are proteins made by specialised white blood cells: B cells (B lymphocytes) and plasma cells. The function of antibodies is to recognise infectious agents so that they can be blocked. Two examples of antibody deficiencies are:
• Common Variable Immune Deficiency (CVID) is the most common form of antibody deficiency, usually presenting with recurrent chest and sinus infections in childhood or early adulthood, although most cases are diagnosed in adults. Early recognition can prevent bronchiectasis -permanent damage to the lungs.
CVID affects both males and females. Most people with CVID are not diagnosed until 30 to 40 years of age however around 1 in 5 people with CVID will have symptoms of CVID in childhood, from 2 to 16 years of age. Normal antibody responses are required to fight infections caused by germs such as bacteria, moulds, parasites and viruses. Most people with CVID have recurrent infections due to their reduced antibody responses. These infections usually occur in the ears, sinuses, nose and lungs, which may start in early childhood, adolescence or adult life. Other common infections in CVID include conjunctivitis and persistent diarrhoea. Unusual infections may also occur, including meningitis and blood stream infection. Although people who don’t have CVID can also suffer from these infections, the difference in people with CVID is that the infections are unusually recurrent, prolonged, severe or resistant to normal treatment.When infections are unrecognised or not treated properly in people with CVID, they can result in damage to organs in the body, such as the sinuses, causing chronic sinusitis, or the airways of the lung (bronchi), causing bronchiectasis. This organ damage can lead to tissue damage, causing ongoing mucus secretion and the persistent need to clear phlegm (sputum) or thick white, yellow or green mucus from the nose. Once tissue damage is established, infection tends to become more persistent and difficult to clear.
Common Variable Immune Deficiency (CVID) resources
• X-linked Agammaglobulinaemia can present in infancy, later childhood or adulthood. Infants with this deficiency develop recurrent pus producing infections of the ears, lungs, sinuses and bones and can get infections in the bloodstream and internal organs. They are also susceptible to certain viruses such as hepatitis and polio.
X-linked Agammaglobulinaemia resources
X-linked or Autosomal Hyper IgM Syndrome resources
Selective IgA Deficiency
IgG Subclass Deficiency and Specific Antibody Deficiency