What are the causes of pure red cell aplasia?

Pure red cell aplasia is caused by a decrease in red blood cells in the bone marrow. Studies have found that it is caused by thymoma, viruses, infections and other reasons. A variety of antibodies will be produced in the patient's serum, such as antinuclear antibodies, lupus erythematosus factors, etc. If not treated in time, the harm will be very serious.

1. Overview

Pure red cell aplasia (PRCA) refers to an anemia caused by a significant decrease or absence of red cell lines in the bone marrow. In 1922, Kaznelson first separated this disease from aplastic anemia, and since then this disease has gradually received widespread attention. It is closely related to autoimmunity and thymic tumors. This disease is now divided into two types: congenital and acquired. Acquired disease is divided into acute and chronic. The acute one is also called acute hematopoietic stagnation. Chronic acquired pure red blood cell aplastic anemia is a rare disease. It is characterized by a significant decrease in erythroid cells in the bone marrow and is often accompanied by thymoma. This complication was first discovered by Opsahl in 1939 and has been reported frequently since then. According to statistics, about 20%-50% of cases are complicated by thymoma, which may be related to the cause and onset of the disease.

The patients are mostly aged 20-67 years old, and are more common in middle-aged people. Some are combined with thymoma, and thymoma combined with pure red cell aplastic anemia accounts for about 7% of all thymoma patients. There were more females than males in the pure red cell aplastic anemia with thymoma group (2:1), but there were more males than females in the pure red cell aplastic anemia without thymoma group. It should be pointed out that some pure red blood cell aplastic anemia develops leukopenia and thrombocytopenia during the course of the disease, becoming general aplastic anemia.

2. Causes

This disease is caused by thymoma, viruses, infections, lymphoproliferative diseases and drugs, and the cause of some cases is unknown. The disease is often related to immunity. Some cases of this disease are complicated by thymoma, suggesting that immunity plays an important role in the onset of the disease.

3. Clinical manifestations

Anemia is the only symptom and sign in patients with this disease. If combined with thymoma, the tumor is also smaller and difficult to detect through physical examination. Generally, there are no congenital abnormalities. The blood picture showed normocytic normochromic anemia with a decrease in the absolute value of reticulocytes; the white blood cell and platelet counts were normal. The number of erythroid cells in the bone marrow is significantly reduced, even disappearing when 500 nucleated cells are counted, but the number of granulocyte and megakaryocyte cells is not reduced. There was no obvious abnormality in the morphology of various cells, and occasionally there was an increase in eosinophils.

The patients' serum iron and serum iron saturation increased. Iron kinetic studies showed that the clearance time of plasma 59Fe was significantly prolonged and the iron utilization rate was reduced, which was consistent with the finding of a decrease in the erythroid system in the bone marrow. Red blood cell survival time is normal. Serum protein electrophoresis is normal in most patients, but some patients have increased or decreased γ-globulin. There are many kinds of antibodies in the serum, such as cold agglutinins, warm agglutinins, cold hemolysins, heterophilic antibodies, antinuclear antibodies, lupus erythematosus factor, etc.