Autoimmunity and PIDs

What is autoimmunity?

Autoimmunity happens when the body starts to attack its own tissues and organs. It is caused by changes in how the immune system works. The immune system simply stops recognising the difference between what is ‘self’ (auto – meaning belonging to the body) and shouldn’t be attacked, and foreign organisms that should be.

The effects of this autoimmune attack are inflammation and damage to the tissues of the body. This can include damage to the upper airways, lungs, joints, nervous system, liver, gut, thyroid gland, blood cells and indeed any tissue or organ.

How does this happen?

It is due to an overactive, faulty immune system. The immune system starts to produce white blood cells or antibodies that react against particular markers in certain tissues or organs. This is known as ‘organ-specific’ autoimmune disease. Or, sometimes, antibodies are produced against markers spread throughout the body in many tissues or organs. This is known as ‘non-organ specific’ autoimmune disease.

Which PIDs are particularly associated with autoimmune complications?

The primary immunodeficiencies (PIDs) most often associated with the development of autoimmunity are:

common variable immune deficiency (CVID)
IgA deficiency
Wiskott–Aldrich syndrome
Good syndrome
hyper IgM syndrome
complement component deficiencies.

In some kinds of PIDs, autoimmune disease is a central and principal part of the condition. These types of PIDs include:

autoimmune lymphoproliferative syndrome (ALPS)
immune dysregulation + polyendocrinopathy + enteropathy + X-linked inheritance (IPEX) syndrome
autoimmune polyendocrinopathy + candidiasis + ectodermal dysplasia (APECED) syndrome.

What autoimmune diseases are associated with PIDs?

Different ‘organ-specific’ and ‘non-organ specific’ autoimmune diseases are associated with PIDs. These include:

Tissue or organ affected	Example of the resulting autoimmune disorder
Blood/bone marrow	Anaemia caused by low numbers of white blood cells and platelets.
Bones, joints, connective tissues	Rheumatoid arthritis, Sjogren’s syndrome, dermatomyositis, systemic lupus erythematosus (often referred to as SLE or lupus).
Liver	Liver disease known as autoimmune hepatitis.
Lungs	Lung diseases affecting the tissue and space around the air sacs of the lungs. These diseases are known as interstitial lung diseases.
Pancreas	Diabetes, especially Type 1 (insulin dependent) diabetes.
Skin	Vitiligo – loss of skin pigment which results in white patches on the skin. Alopecia – abnormal loss of hair.
Stomach and bowel	Autoimmune gastritis – inflammation of the stomach lining caused by autoimmunity against the stomach. Pernicious anaemia – the failure to make enough red blood cells. This is usually associated with autoimmune gastritis. Inflammatory bowel disease causing diarrhoea.
Thyroid gland	Diseases that affect the function of the thyroid gland. These include Hashimoto’s disease, Graves’ disease and myxoedema.