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The quick answer to this is yes_ although it may seem strange that

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					PiA INFORMATION


Information Sheet No.9                                         Primary Immunodeficiency Association

Autumn 2000




                  Autoimmune disease,allergy,
                 and primary immunodeficiency
              Can you have an autoimmune disease or allergy and a primary
                          immunodeficiency at the same time?

The quick answer to this is yes, although it may seem strange that someone who has an immune
system which functions deficiently may, at the same time, also have an immune system which is
overactive and produces autoimmune or allergic problems!

The immune system consists of several overlapping layers of defence, which are designed to protect
the tissues and cells of the body. These different parts of the immune system work together in
balance and each of them to some extent or other depends on and controls other parts. So, if one of
the parts is not working properly, for instance in a primary immunodeficiency, then it can disturb the
balance and control of other parts of the immune system. It is therefore possible, and in fact quite
common, to have a situation where there is a deficiency of one part of the immune defences
(immunodeficiency) whilst at the same time another part is overactive (which results in autoimmune
disease or allergy).

In autoimmune disease tissue or cell damage is caused by special white blood cells, T- or B-lympho-
cytes, which incorrectly react to normal parts of the cells, organs and tissues (called autoantigens).
These lymphocytes mistakenly think they are encountering dangerous, foreign bugs and make an
immune response against the autoantigens. This overactive, faulty immune response may be directed
against autoantigens which are present only in certain tissues or organs (“organ specific” autoimmune
disease), or against autoantigens which are spread throughout the body in many tissues or organs
(“non-organ specific” autoimmune disease).

Allergy is the result of the body incorrectly producing a specific class of immunoglobulin (antibodies)
– called IgE - and this reacts with things in the environment called “allergens”.

Examples of these are pollens, house dust mite droppings, pets (horses, cats and dogs) and various
foods (like eggs, fish, nuts and cereals). When the allergen reacts with the IgE it results in allergic
disorders like asthma, some varieties of rhinitis (inflammation of the nose), skin problems and
sometimes life-threatening anaphylactic (shock) reactions.
Autoimmune and allergic problems can be found in many different kinds of primary immuno-
deficiency including those which affect T cells, those which affect B cells and antibody production
and also in those which affect both T and B cells. However, patients with IgA deficiency or Common
Variable Immunodeficiency (CVID) seem to have the highest frequency of these complications.
Autoimmune disease is found in about 20% of CVID patients and is more common in females than
males (this higher incidence among females is also found in people who do not have any
immunodeficiencies).

There are many different “organ-specific” and “non-organ specific” autoimmune diseases which have
been found in people with primary immunodeficiencies. These include:
    Thyroid disease
    Diabetes
    Vitiligo (loss of areas of pigment on the skin which results in white patches )
    Alopecia (abnormal hair loss)
    Autoimmune gastritis (stomach inflammation)
    Pernicious anaemia
    Loss of parts of the blood such as red and white cells and platelets
    Liver disease
    Connective tissue disorders like rheumatoid arthritis, Sjogrens syndrome, dermatomyositis
      and systemic lupus erythematosus (often called SLE or lupus)
Autoimmune disease may also play a part in causing some varieties of inflammatory bowel diseases.

Autoimmune diseases and allergic reactions can cause inflammation and damage in the upper airway,
lungs, joints, nervous system, gut and indeed any tissue or organ. It is important, however, both for
medical and nursing staff and for patients to understand that inflammation in these areas may also
be the result of infection, to which immunodeficient patients are prone. For instance, a red, hot,
swollen joint in an antibody deficient patient may be the result of an autoimmune process or it may
be caused by an infection. Similarly, sinus inflammation may be caused by an allergic reaction to
allergens (like pollen) in the air but, in an individual with antibody deficiency, might also be caused by
a bacterial infection. It is important to distinguish between these causes and to treat each problem
appropriately. However, sometimes this can be difficult, as the usual tests used to help
diagnose autoimmune or allergic disease may not give reliable results in some immunodeficient
patients.


Dr Richard Herriot
Consultant Immunologist, Aberdeen
PiA Medical Advisory Panel


        Medical information published by the PiA is approved by our Medical Advisory Panel.
         However, it is intended for general guidance only, and should not be substituted
         for the essential personal consultation you need with your own doctor/consultant.
PiA, Alliance House, 12 Caxton St, LONDON SW1H 0QS,
                 Tel. 020 7976 7640, Fax 020 7976 7641
                                    Email: info@pia.org.uk
                                     Web: www.pia.org.uk

				
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