Fc rosette inhibition by serum of patients with infective endocarditis

The inhibition of lymphocyte Fc rosette formation was studied in sera of patients with infective endocarditis. The pretreatment value of sensitised chicken erythrocyte (EA) rosette inhibition was 37.9 +/- 7.8%; in controls it was 4.1 +/- 1.3% (P less than 0.001). The posttreatment value was 2.8 +/- 2.1%. Six patients had culture-negative infective endocarditis, and in them the value of EA rosette inhibition was higher than in the others (42.3 +/- 7.1%). The measurement of circulating immune complexes may be a diagnostic tool in patients with culture-negative infective endocarditis.