Question

What is type of infections a person with selective IgA deficiency has the higher risk to suffer from?

Answer 1

Classification of primary immunodeficiency diseases :

• Humoral immunodeficiency -B cell defects
• Cellular immuno deficiency - T cell defects
• Combined immuno deficiencies - B and T cell defects
• Disorders of phagocytosis
• Disorders of complement

The selective Ig A deficiency comes under humoral immunodeficiency diseases. Selective Ig A deficiency condition where there is lack of immunoglobulin or antibody A only.

Ig A deficiency is the most common of all primary immunodeficiency diseases. In normal healthy individuals, Ig A is mostly present in the mucosal secretions and involves in providing immunity at mucosal sites of intestine and respiratory tract.

The weakened mucosal defence is due to IgA deficiency predispose the patients to recurrent infections. Patients are at a risk of developing infections such as-

• sino pulmonary infections,
• diarrhoea ,
• Allergy , sepsis.
• Sometimes , there is also significant association with autoimmune diseases-rheumatoid arthritis , lupus, ataxia telangiectasia , inflammatory bowel disease etc.

Pathogenesis :

There is blockade of terminal differentiation of Ig A secreting B cells to plasma cells.

This is inturn due to the altered T cell production of cytokines, that drive the Ig A response (eg.TGF beta , IL-5) or due to intrinsic B cell defect.

The levels of immunoglobulins are usually normal or sometimes excess.

Treatment

There is no specific treatment for selective Ig A deficiency. Intravenous immunoglobulin is not indicated.Prophylactic antibiotics are useful in patients with recurrent sinopulmonary infections and supportive treatment is given.Prognosis is good in most of cases.