What causes aplastic anemia

Aplastic anemia is mainly caused by exposure to chemical toxins, ionizing radiation, viral infections, drug side effects, and immune abnormalities. The pathogenesis involves damage to hematopoietic stem cells, abnormal bone marrow microenvironment, and immune system attack on hematopoietic tissue.

1. Chemical toxins:

Long term exposure to benzene compounds is a clear pathogenic factor, as these substances cause bone marrow failure by damaging the DNA of hematopoietic stem cells. Occupational exposure groups such as painters and rubber product producers are at higher risk, and benzene released from inferior materials in home decoration may also trigger diseases. Some insecticides and hair dyes contain benzene derivatives, and frequent exposure may increase the risk of illness.

2. Ionizing radiation:

High dose radiation can directly kill hematopoietic stem cells, and victims of nuclear accidents or radiation therapy may experience bone marrow suppression. Low dose long-term exposure, such as regular monitoring of blood routine by radiation medical personnel, can interfere with the cell division cycle and lead to apoptosis of hematopoietic precursor cells. Bone marrow is more than 10 times more sensitive to radiation than lymphocytes.

3. Viral infection:

Hepatitis B virus, EB virus, etc. can induce autoimmune reactions through molecular simulation mechanisms, mistakenly attacking hematopoietic cells. About 15% of pediatric patients are associated with parvovirus B19 infection, which specifically invades red blood cell precursor cells. Late stage HIV infection is often accompanied by a decrease in whole blood cells, and the virus can directly infect hematopoietic progenitor cells.

4. Drug factors:

Chloramphenicol and sulfonamide antibiotics may inhibit hematopoiesis through mitochondrial toxicity, while antipyretic analgesic prednisone can induce allergic reactions and damage bone marrow. Antitumor drugs such as alkylating agents may cause irreversible bone marrow damage when treating leukemia, and there have also been related case reports of some antiepileptic drugs, gold preparations, etc. Drug related relapse usually occurs 2-3 months after medication.

5. Immune abnormalities: About 70% of patients have T lymphocyte hyperfunction, and excessive secretion of cytokines such as gamma interferon can inhibit hematopoiesis. Patients with autoimmune diseases such as thymoma and systemic lupus erythematosus are prone to aplastic anemia, and the decrease of the number of regulatory T cells in the hematopoietic microenvironment leads to the imbalance of immune surveillance. Anti hematopoietic precursor cell antibodies can be detected in some cases.

To prevent aplastic anemia, it is necessary to avoid exposure to benzene based chemicals, and newly renovated houses should be fully ventilated before moving in. Occupational exposure individuals are advised to have their blood routine checked every six months, and to be alert for persistent fatigue after viral infection. Be cautious of drugs that may damage the bone marrow, and if necessary, cooperate with liver protection treatment under the guidance of a doctor. Maintaining a regular schedule and balanced diet, supplementing with foods rich in iron and folate such as animal liver and dark green vegetables in moderation, and moderate aerobic exercise can improve bone marrow microcirculation. When symptoms such as skin and mucosal bleeding, repeated infections, etc. occur, timely bone marrow puncture examination should be performed.