Circulating immune complex

The substance formed by the combination of antigen and corresponding antibodies is called immune complex. Immune complex is combined with complement and other immunoactive substances and deposited on the blood vessel wall, which can cause tissue damage and vasculitis and cause a series of diseases, such as lupus erythematosus. Immune complex can be detected in circulating blood, so it is called circulating immune complex. Although the measurement of circulating immune complexes has no specific diagnostic significance, it has certain value in judging the activity of the disease and guiding the treatment. There are many methods for measuring circulating immune complexes. Here we only introduce the commonly used clinical polyethylene glycol method. The effect of circulating immune complexes with polyethylene glycol is expressed as turbidity changes, and the amount of immune complexes can be reflected according to the size of turbidity. If the turbidity is large, it means that circulating immune complexes are increased in the blood and the disease is active, but it has no specific value for diagnosis.