Immunodeficiency diseases are defects of the immune system, and impair the functioning of the immune system. Patients are more susceptible to recurrent and persistent infections. Other symptoms can be common as well.
There are more than 70 primary immune deficiencies (PIDs), and these are grouped according to which elements fo the immune system are affected. Most PIDs are relatively rare disorders:
- Antibody deficiency disorder - defects in B cells which produce immunoglobulin.
- T cell deficiencies - affect the function of destroying infected cells or helping other immune cells.
- Combined immunodeficiencies (CIDs) - both T cells and the production of antibodies are defective.
- complement system deficiency
- phagocytic cells deficiency - impairs the anti-microbial immunity
- Infections are treated with antibiotics, and often require high doses with prolonged treatment. Antibody deficiencies can be treated with intravenous immunoglobulin substitution therapy. Bone marrow transplantation can be an effective treatment for severe combined immunodeficiencies. As well, enzyme substitution therapy may be employed in certain metabolic discorders like ADA (Adenosine deaminase) and PNP (Purine nucleoside phosphorylase) deficiency.