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Lymphocytopenia is a condition marked by an abnormally low level of lymphocytes in the blood. Lymphocytes are a specific type of white blood cell with important functions in the immune system.


Lymphocytes normally account for 15-40% of all white cells in the bloodstream. They help to protect the body from infections caused by viruses or fungi. They also coordinate the activities of other cells in the immune system. In addition, lymphocytes fight cancer and develop into antibody-producing cells that neutralize the effect of foreign substances in the blood.
Lymphocytopenia is the result of abnormalities in the way lymphocytes are produced, make their way through the bloodstream, or are lost or destroyed. These conditions can result from congenital or drug-induced decreases in the body's ability to recognize and attack invaders.

Causes and symptoms

Lymphocytopenia has a wide range of possible causes:
  • AIDS and other viral, bacterial, and fungal infections
  • Chronic failure of the right ventricle of the heart. This chamber of the heart pumps blood to the lungs.
  • Hodgkin's disease and cancers of the lymphatic system
  • A leak or rupture in the thoracic duct. The thoracic duct removes lymphatic fluid from the legs and abdomen.
  • Leukemia
  • Side effects of prescription medications
  • Malnutrition. Diets that are low in protein and overall calorie intake may cause lymphocytopenia.
  • Radiation therapy
  • High stress levels
  • Trauma.
The symptoms of lymphocytopenia vary. Lymphocytes constitute only a fraction of the body's white blood cells, and a decline in their number may not produce any symptoms. A patient who has lymphocytopenia may have symptoms of the condition responsible for the depressed level of lymphocytes.


Lymphocytopenia is most often detected when blood tests are performed to diagnose other diseases.


Treatment for lymphocytopenia is designed to identify and correct the underlying cause of the condition.
Drug-depressed lymphocyte levels usually return to normal a few days after the patient stops taking the medication.

Key terms

B lymphocyte — A type of lymphocyte that circulates in the blood and lymph and produces antibodies when it encounters specific antigens. B lymphocytes are also called B cells.
Lymph — A clear yellowish fluid circulated by the lymphatic system. The lymph carries mostly lymphocytes and fats.
Lymphocyte — A specific type of white blood cell that is important in the production of antibodies.
A deficiency of B lymphocytes, which mature into antibody-producing plasma cells, can result in abnormally low lymphocyte levels. When the number of B lymphocytes is low, the patient may be treated with antibiotics, antifungal medications, antiviral agents, or a substance containing a high concentration of antibodies (gamma globulin) to prevent infection.
It is not usually possible to restore normal lymphocyte levels in AIDS patients. Drugs like AZT (azidothymidine, sold under the trade name Retrovir) can increase the number of helper T cells, which help other cells wipe out disease organisms.


Very low levels of lymphocytes make patients vulnerable to life-threatening infection. Researchers are studying the effectiveness of transplanting bone marrow and other cells to restore normal lymphocyte levels. Gene therapy, which uses the body's own resources or artificial substances to counter diseases or disorders, is also being evaluated as a treatment for lymphocytopenia.



Berktow, Robert, et al., editors. Merck Manual of Medical Information: Home Edition. Whitehouse Station, NJ: Merck Research Laboratories, 1997.


A reduction, relative or absolute, in the number of lymphocytes in the circulating blood.
[lympho- + G. penia, poverty]


/lym·pho·cy·to·pe·nia/ (-si″to-pe´ne-ah) lymphopenia; reduction of the number of lymphocytes in the blood.


Etymology: L, lympha + Gk, kytos, cell, penes, poor
a decreased number of lymphocytes in the peripheral circulation, associated with immunodeficiency, neoplasm, or chemotherapy. Compare alymphocytosis. See also agranulocyte.


A reduction, relative or absolute, in the number of lymphocytes in the circulating blood.
Synonym(s): lymphocytopenia.
[lympho- + G. penia, poverty]

lymphocytopenia (limˈ·fō·sīˈ·tō·pēˑ·nē·),

n an abnormally low number of lymphocytes in the blood due to malignancy, malnutrition, drugs, infectious mononucleosis, or a primary hematologic disorder.

lymphocytopenia (lim´fōsī´tōpē´nēə),

n a decrease in the normal number of lymphocytes in the circulating blood. Various limits are given (e.g., a total number less than 600/mm3). It may be associated with agranulocytosis, hyperadrenocorticism, leukemia, advanced Hodgkin disease, irradiation, and acute infections with neutrophilia.


see lymphopenia.

lymphopenia, lymphocytopenia

decrease in the number of lymphocytes of the blood.
References in periodicals archive ?
The patient had CD4 counts of 54 and 72 on two separate measurements during the course of his stay, which fulfilled criteria for diagnosis of Idiopathic CD4+ Lymphocytopenia (ICL).
Supplementation with sulfur-containing amino acids (cysteine, theanine) also attenuated exercise-induced lymphocytopenia [73].
The hematological changes associated with malaria include anaemia and thrombocytopenia; however lymphocytopenia, leucopenia, leukocytosis, neutropenia and neutrophilia have also been reported in literature.
Idiopathic CD4 lymphocytopenia (ICL) is a condition characterized by the decrease in CD4 count with consequent opportunistic infections.
Hematological and biochemical tests may show elevated erythrocyte sedimentation rate, anemia, lymphocytopenia, increased liver enzymes, hypercalcemia and increased serum angiotensin enzyme (S-ACE).
Zinc deficiency may contribute to some of the symptoms and complications of cirrhosis, including skin lesions, anorexia, night blindness, decreased taste acuity, testicular atrophy, lymphocytopenia, and increased susceptibility to infections, in addition, zinc deficiency may reduce the capacity of the liver to synthesize urea, thereby increasing ammonia levels and contributing to the development of hepatic encephalopathy.
There are several possible explanations for a high rate of indeterminate and nonreactive results, including the presence of lymphocytopenia and/or inflammatory and immunosuppressive conditions, as well as hypoalbuminemia, which suggests poor nutritional status (12), and there is a high probability that some of these conditions could have existed among the subjects of the current study.
Adverse events tended to fall into the categories expected for any immunomodulatory agent: lymphocytopenia, CV effects, increased rates of infection, macular edema, liver-enzyme abnormalities, and neoplasms.
Lymphocytopenia cases were more frequent in the DM group (11%) and less frequent in the DM-TB group (4.
Moreover, by inducing CD4+ T cell loss by apoptosis, immune activation may further be central to the increased rate of CD4+ T cell turnover and eventual development of CD4+ lymphocytopenia (4).