Lymphocytes are a white blood cell with important functions in the immune system.
Lymphocytopenia may be present as part of a pancytopenia, when the total numbers of all types of blood cells are reduced.
[3] 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,[4] severe stress,[5] intense or prolonged physical exercise (due to cortisol release),[6] rheumatoid arthritis, sarcoidosis,[7] multiple sclerosis,[8] 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 that have spread to involve the bone marrow, such as leukemia or advanced Hodgkin's disease,[9][10] also cause lymphocytopenia.