Primary Immune Deficiency

Primary Immune Deficiencies (or PIDs as they are commonly known) are disorders in which the patient's immune defences are absent or decreased as a result of a problem of the body itself, normally as the result of a genetic problem. They are distinguished from secondary immune deficiencies because there is no mediating agent which gives rise to the problem, as occurs in Human Immunodeficiency Virus (HIV). There are many different PIDs ranging from the serious and life threatening (such as severe combined immunodeficiency or SCID) through to chronic symptomatic disorders (common variable immunodeficiency [CVID] and other a- and hypo-gammaglobulinaemias) through to subclinical conditions (the majority of cases of selective IgA deficiency). PIDs are confusing. There are lots of abbreviations, and immunology (the study of the immune system) is a complex topic which can be daunting when you are first diagnosed. As someone with CVID and with a background in the biological sciences, my aim here is to explain some of the terminology and outline how the disorders arise. I'll discuss what different types of cells do, and some of the most common treatment options. However, none of the advice on this site should be seen as a substitute for consulting with a qualified physician. I cannot possibly know the details of every individual's circumstances, and what is right for one patient may be inappropriate for another. For this reason, I also cannot enter into personal correspondence about a particular case.