Acute phase reactants and complement activation in patients with acute myocardial infarction.

The acute phase proteins, C-reactive protein (CRP), orosomucoid, alpha 1-antitrypsin and haptoglobin, the native complement components C3 and C4, activation products of C3, and the terminal SC5b-9 complement complex were quantified in samples obtained on admittance and on days 1, 2, 3 and 6 in 21 patients with non-complicated acute myocardial infarction (AMI) and in 22 controls. For all proteins peak and median concentrations were higher in the AMI group than in the controls, but the difference was significant only for CRP and orosomucoid. Median CRP concentration was 46 mg/l in the AMI group and 2.5 in the control group. The corresponding orosomucoid concentrations were 1.6 and 1.2 g/l. There was no correlation between the concentration of CRP in peripheral blood and the degree of complement activation. Furthermore, no correlation was observed between complement activation and the size of infarction. The present study cannot demonstrate that the increased concentrations of CRP and other acute phase reactants observed in patients with AMI, are associated with systemic fluid-phase complement activation. Furthermore, the complement activation previously shown locally in infarcted myocardium cannot be demonstrated systemically in non-complicated AMI.