The immune system in A-T

Immunological problems

A large proportion (between 60 and 80%) of patients with Ataxia-Telangiectasia have an impaired immune system (immunodeficiency). This usually shows itself in the form of  recurrent or severe infections. However, the immunodeficiency is variable with some individuals significantly affected and others not at all. Those affected are particularly at risk of repeated lung (chest) and sinus (nasal) infections which if unchecked may cause permanent damage to these organs.

Why does it happen?

We are working to understand the mechanism of the immunodeficiency but we do know that several parts of the immune system are involved. Key elements of this system are antibodies (also known as immunoglobulins) and specific immune cells that can recognise germs (T and B cells). When these are being generated, the DNA in the cell needs to be broken up and then reconstructed in a slightly different order. This process allows diversity in the immune system so it can respond to the numerous different bugs the body comes into contact with.

Properly functioning repair processes are essential to produce fully working antibodies and specific immune cells. We know that the ATM protein plays a key role in DNA repair and so it is likely that this process for producing antibodies and other immune cells is affected in people with A-T.

In addition to this, we know that the thymus gland is poorly functioning in people with A-T. The thymus gland lies within the chest and is essential for the development of T cells which are necessary in the co-ordination of the immune system. It is likely therefore that impairment of the thymus gland also contributes to the immunodeficiency.

Managing Immunodeficiency

In view of this, it is important that any person with A-T is reviewed by a doctor who understands the immune system if they are getting infections. Blood tests can be taken to check the different parts of the immune system and in some cases, the doctor may prescribe antibiotics long term to protect against infection. In addition, about 10% of people with A-T need to have immunoglobulin (or antibody) replacement therapy to keep them well. This involves regular infusions either under the skin (subcutaneous) or into a vein (intravenous). Often this can be easily given at home by a family member once they have been trained by hospital staff but can also be given in hospital if families prefer.

 

 

ATM Antibody image