Low complement is common in acute and chronic nephritis, liver diseases such as chronic active hepatitis and cirrhosis, and autoimmune diseases such as systemic lupus erythematosus.
1. Patients with acute and chronic nephritis may have decreased complement. For example, in the early stage of nephritis after acute streptococcal infection, there is a significant decrease in complement C3, which can be improved after the disease recovers. Some patients with membranoproliferative glomerulonephritis may also have different degrees of decrease in complement C1q, C3 and C4.
2. Patients with liver diseases may also have decreased complement, such as chronic active hepatitis, cirrhosis, hepatic necrosis, and so on. This kind of patients is usually due to the decreased synthesizing ability of the liver, which leads to the decrease of complement in patients.
3. In autoimmune diseases, the formation of autoantibodies and immune complexes causes an increase in complement depletion, resulting in a decrease in complement level. Common diseases such as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and so on.
Patients with low complement levels are advised to consult the rheumatology and immunology department of regular hospitals to clarify the cause and carry out relevant treatments under the guidance of doctors.