Lymphopenia

Lymphopenia is a decrease in the total number of lymphocytes (<1000 / µl in adults or <3000 / µl in children under 2 years of age).

The consequences of lymphopenia include the development of opportunistic infections and an increased risk of cancer and autoimmune diseases. If lymphopenia is detected when performing a general blood test, diagnostic tests should be performed for immunodeficient states and analysis of lymphocyte subpopulations. The treatment is aimed at the underlying disease.

The normal number of lymphocytes in adults is from 1000 to 4800 / μl, in children under 2 years of age from 3000 to 9500 / μl. At the age of 6, the normal lower limit of lymphocytes is 1500 / µl. Both T and B lymphocytes are present in the peripheral blood. About 75% are T-lymphocytes and 25% are B-lymphocytes. Since the proportion of lymphocytes is only 20-40% of the total number of blood leukocytes, lymphopenia may not be determined by a blood test without determining the leukocyte formula.

Almost 65% of T-blood cells are CD4 T-lymphocytes (helpers). Most patients with lymphopenia have a decrease in the absolute number of T-cells, especially the number of CD4 T-cells. The average number of CD4 T cells in adults is 1100 / μl (300 to 1300 / μl), the average number of another large subpopulation of T lymphocytes, CD8 T cells (suppressors) is 600 / μl (100-900 / μl).

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]

Causes of Lymphopenia

Congenital lymphopenia is manifested in congenital immunodeficiency diseases and diseases in which there is a violation of the production of lymphocytes. In some hereditary diseases, such as Wiskott-Aldrich syndrome, there is a deficiency of adenosine deaminase, purine nucleoside phosphorylase, there is an increased destruction of T-lymphocytes. In many hereditary diseases there is also a lack of antibodies.

Acquired lymphopenia occurs with a large number of different diseases. Worldwide, the most common cause of lymphopenia is insufficient protein nutrition. The most common infectious disease that causes lymphopenia is AIDS, in which HIV-infected CD4 T cells are destroyed. Lymphopenia may be due to impaired lymphocyte production caused by damage to the structure of the thymus gland or lymph nodes. In acute viremia caused by HIV or other viruses, lymphocytes can undergo accelerated destruction caused by an active infectious process, captured by the spleen or lymph nodes, or migrate to the respiratory tract.

Prolonged psoriasis therapy with psoralen and ultraviolet radiation can destroy T-cells.

Iatrogenic lymphopenia is caused by cytotoxic chemotherapy, radiation therapy, or the introduction of anti-lymphocytic immunoglobulin. Glucocorticoids can induce lymphocyte destruction.

Lymphopenia can occur in autoimmune diseases such as SLE, rheumatoid arthritis, myasthenia gravis, and enteropathy, with loss of protein.

Causes of Lymphopenia

Congenital

Acquired

Aplasia of lymphopoietic stem cells. Ataxia-telangiectasia. Idiopathic CD4 + T lymphopenia. Immunodeficiency with thymoma. Severe combined immunodeficiency associated with an anomaly of the γ chain of the interleukin-2 receptor, deficiency of ADA or PNP, or of unknown etiology. Wiskott-Aldrich syndrome

Infectious diseases, including AIDS, hepatitis, influenza, tuberculosis, typhoid fever, sepsis. Malnutrition with alcohol, insufficient protein or zinc deficiency. Iatrogenic after the use of cytotoxic chemotherapy, glucocorticoids, high doses of psoralen and ultraviolet radiation, immunosuppressive therapy, radiation or drainage of the thoracic duct. Systemic diseases with autoimmune components: aplastic anemia, Hodgkin's lymphoma, myasthenia gravis, protein-losing enteropathy, rheumatoid arthritis, SLE, thermal injury

ADA - adenosine deaminase; PNP - purinucleoside phosphorylase.

[12], [13], [14], [15], [16], [17], [18], [19]

Symptoms of lymphopenia

Lymphopenia itself is usually asymptomatic. However, signs of associated diseases, the absence or reduction of tonsils or lymph nodes indicate cellular immunodeficiency. The most common symptoms of lymphopenia are skin diseases such as alopecia, eczema, pyoderma, and telangiectasia; signs of hematological diseases, such as pallor, petechiae, jaundice, ulceration of the oral mucosa; generalized lymphadenopathy and splenomegaly, which may indicate the presence of HIV infection.

In patients with lymphopenia, recurrent infections or infections caused by rare microorganisms such as Pneumocystis proved (formerly P. Carinii), cytomegalovirus, rubella, chicken pox with pneumonia and lymphopenia are common, which suggests immunodeficiency. In patients with lymphopenia, counting of lymphocyte subpopulations and determination of the level of immunoglobulins is necessary. Patients with frequent recurrent infections should be thoroughly examined in order to assess immunodeficiency, even if initial screening tests are normal.

[20], [21], [22]

Lymphopenia treatment

Lymphopenia disappears when the causative factor or disease that caused it is removed. The purpose of intravenous immunoglobulin is indicated if the patient has a chronic IgG deficiency, lymphopenia, and recurrent infections. Hematopoietic stem cell transplantation can be successfully applied in patients with congenital immunodeficiency.

[23], [24], [25], [26]