What causes Evans syndrome?

There are more and more various diseases, some are rare diseases, some are unclear diseases, and some diseases have English pronouns. Evans syndrome is a common disease in Western populations, but it does not mean that Chinese people will not have it. Some people have special physical constitutions, and there are a few patients who will have it. Evans syndrome is a common disease and a systemic disease. Because the causes of the disease are complicated, it will most likely cause many complications, and the course of the disease is very complicated. It may also lead to lymphotropic virus infection, so you must understand it in time and prevent the disease from getting worse.

What causes Evans syndrome?

1. Causes

The cause of Evans syndrome is unknown. It may occur simultaneously or sequentially with the following diseases: systemic lupus erythematosus, Graves' disease, pregnancy, diabetes, myelodysplastic syndrome, tuberculosis, hepatitis B or C virus infection, disseminated intravascular coagulation, bronchiolitis obliterans organizing pneumonia, lymphoproliferative diseases (such as chronic lymphocytic leukemia, lymphoma, thoracic adenoma, multiple myeloma) and after transplantation. Domestic reports show that secondary cases are mostly autoimmune diseases, especially connective tissue diseases such as systemic lupus erythematosus. Some other cases are idiopathic and no clear clues to the cause have been found.

2. Pathogenesis

The pathogenesis of Evans syndrome is unclear, and there may be defects in humoral immunity and cellular immunity. The link to genetic factors is uncertain.

1. Deficiency of humoral immunity: Evans syndrome patients may have autoantibodies directly targeting red blood cells, platelets or neutrophils in their serum. However, there is no cross-reactivity between these antibodies. In 1976, Fagiolo reported 32 adult patients with AIHA. Nineteen patients also had thrombocytopenia and 19 patients had leukopenia, of which 91% had antiplatelet antibodies and 81% had antileukocyte antibodies. In these patients, there was no cross-talk between the types of leukocyte and/or platelet antibodies and erythrocyte antibodies. Kakaiya et al. also confirmed the non-cross-reactivity of red blood cell antibodies and platelet antibodies through the 125I-staphylococcal protein labeling method. Pegels et al. also confirmed through adsorption and elution experiments that autoantibodies against red blood cells, white blood cells and platelets correspond to different antigens respectively, and there is no cross-reaction between the three. The most common antigen on the surface of red blood cells is IgG+C3, followed by IgG and C3. In some cases, cold antibodies are also present in the serum. There are few reports on antibodies on the platelet surface, and most of them are IgG type.

2. The onset of cellular immunodeficiency Evans syndrome may be related to abnormalities in T lymphocyte subtypes in the blood. Studies have found that patients with Evans syndrome have a decrease in T helper cells (CD4 cells) and an increase in T suppressor cells (CD8 cells), as well as a decreased CD4/CD8 ratio, a decrease in serum immunoglobulins, and a decrease in the in vitro synthesis of IgM and IgG. However, some reports have shown that the number and ratio of CD4 and CD8 cells are normal, and the levels of serum IgM and IgG are elevated. The inconsistency of these findings reflects the heterogeneity of Evans syndrome.