Serial measurement of circulating immune complexes in myocardial infarction.

To study the changes in the quantity of circulating immune complexes in myocardial infarction two serial investigations were performed in 45 and 63 patients, respectively. For the detection of circulating immune complexes in the first series, two methods, a complement consumption test and a Clq-solubility test were used. In the second series, a polyethylene glycol (PEG)-precipitation assay was added to these methods. The incidence of circulating immune complexes was studied on the first, third, seventh, 14th, and 21st day. On the first day the complexes were detected in 59% of the patients. Their occurrence increased in the further samplings to 77%, but from the seventh day their concentration decreased and on the 21st day they were detected in 63%. Three types of changes in the level of circulating immune complexes could be shown. In type I immune complexes were detected in the first days after the onset of the infarction, then, after a gradual decrease, the results became negative. In type II immune complexes appeared in the second to third week and their quantity did not alter during the entire observation period. In type III the circulating immune complexes could be detected throughout the whole period of the study. These changes in their concentration were frequently associated with the clinical course of the disease.