Lymphocytopenia

SignSymptom infobox
Name = Lymphocytopenia


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DiseasesDB = 7677
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ICD9 = ICD9|288.8
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Lymphocytopenia, or lymphopenia, is the condition of having an abnormally low level of lymphocytes in the blood. Lymphocytes are a white blood cell with important functions in the immune system. The opposite is lymphocytosis, which refers to an excessive level of lymphocytes.

Lymphocytopenia may be present as part of a pancytopenia, when the total numbers of all types of blood cells are reduced.

Classification

In some cases, lymphocytopenia can be further classified according to which kind of lymphocytes are reduced. If all three kinds of lymphocytes are suppressed, then the term is used without further qualification.

* In T lymphocytopenia, there are too few T lymphocytes, but normal numbers of other lymphocytes. This is usually caused by HIV infection (resulting in AIDS), but may be Idiopathic CD4+ lymphocytopenia, which is very rare and has no known cause.

* In B lymphocytopenia, there are too few B lymphocytes, but normal numbers of other lymphocytes. This is usually caused by medications that suppress the immune system.

* In NK lymphocytopenia, there are too few natural killer cells, but normal numbers of other lymphocytes. This is very rare.

Causes

The most common cause of temporary lymphocytopenia is a recent infection, such as the common cold.

Lymphocytopenia, but not idiopathic CD4+ lymphocytopenia, is associated with corticosteroid use, infections with HIV and other viral, bacterial, and fungal agents, malnutrition, systemic lupus erythematosus,cite journal | author=W L Ng, C M Chu, A K L Wu, V C C Cheng, K Y Yuen | title=Lymphopenia at presentation is associated with increased risk of infections in patients with systemic lupus erythematosus | journal=Quarterly Journal of Medicine | volume= 99 | issue=1 | pages=37–47 | doi=10.1093/qjmed/hci155 | year=2005 | pmid=16371405] high stress levels,Fact|date=June 2008 rheumatoid arthritis, and iatrogenic (caused by other medical treatments) conditions.

Lymphocytopenia is a frequent, temporary result from many types of chemotherapy, such as with cytotoxic agents or immunosuppressive drugs. Some malignancies in the bone marrow, such as leukemia, also cause lymphocytopenia.

Large doses of radiation, such as those involved with nuclear accidents or medical whole body radiation, may cause lymphocytopenia.

Diagnosis

Lymphocytopenia is diagnosed from the results of a complete blood count. In adults, a lymphocyte level below 1,500 cells/microliter is diagnostic (proof of the condition), and in children, a lymphocyte level below 3,000 cells/microliter is diagnostic.

Prognosis

Lymphocytopenia that is caused by infections tends to resolve once the infection has cleared. Patients with idiopathic CD4+ lymphocytopenia may have either abnormally low but stable CD4+ cell counts, or abnormally low and progressively falling CD4+ cell counts; the latter condition is terminal.

References

External links

* [http://www.merck.com/mmhe/sec14/ch174/ch174d.html Merck]
* [http://www.healthatoz.com/healthatoz/Atoz/ency/lymphocytopenia.jsp Health A-Z]