Determination of circulating immune complexes (CEC) by the ELISA method

Determination of circulating immune complexes (CICs) by ELISA method provides quantitative blood test for C1q-binding circulating immune complexes (CICs) containing IgG in human serum to diagnose rheumatic, autoimmune and infectious diseases, allergies, hematological and tumor diseases. 

Immune complexes are protein aggregates formed by the binding of antibodies to antigens. They are formed as a result of the immune response. Through the activation of the complement system, CICs provoke inflammatory reactions and cause organ damage, such as in glomerulonephritis, Crohn’s disease, ulcerative colitis, rheumatic diseases, and viral/bacterial infections.

Although CICs detection is not disease specific, this test can provide useful information about the immunopathology, course, and prognosis of the disease. The presence of CICs is an indicator of an overloaded immune defense or autoimmune conflict, which should be clarified by narrowly focused tests. 

In autoimmune, microbial, or tumor diseases, CIC test is used as a disease activity marker, as well as to assess systemic manifestations and to monitor treatment. A persistently elevated CIC indicates chronic active disease. Normalization is considered a successful treatment indicator. It is often possible to correlate CIC levels with clinical symptoms and relapses. 

WHO recommends that a second determination should always be performed after a few weeks to assess the persistence of immune complexes in blood circulation. With appropriate therapy, there should be a clear reduction in CICs.