Serial measurement of circulating immune complexes in healthy subjects.

Circulating immune complex (CIC) levels were serially studied in healthy subjects and in normal rats. In human 3 methods (Clq solubility, complement consumption, and granulocyte phagocytosis tests) were used for the measurement of CIC; in rats, CIC levels were determined by the modified complement consumption test. A marked fluctuation in the CIC level was observed both in healthy human subjects and in normal rats. No correlation between results of the 3 assays used for CIC detection was found indicating that not only the level but the composition of CIC changes continuously in health.