USE OF CIRCULATING IMMUNE-COMPLEX LEVELS IN THE SERODIFFERENTIATION OF ENDOCARDITIC AND NON-ENDOCARDITIC SEPTICEMIAS

Distinguishing endocarditic from nonendocarditic septicemias is prognostically and therapeutically important. One hundred two patients with both valvular and nonvalvular sepsis were studied for the presence and quantitation of circulating immune complexes. Ninety per cent of the patients with infective endocarditis versus 50 per cent of septic patients without infective endocarditis had circulating immune complex levels (p < 0.005). Mean circulating immune complex levels in patients with infective endocarditis were significantly higher than in those without infective endocarditis, 106 ± 18.58 μg/ml versus 31 ± 7.4 μg/ml (p < 0.005). Only three of 52 patients without infective endocarditis had circulating immune complex levels > 100 μg/ml, as opposed to 16 of 50 patients with infective endocarditis (p < 0.005). Similarly, one of 52 patients without infective endocarditis has circulating immune complex levels > 200 μg/ml, as opposed to eight of 50 patients with infective endocarditis (p < 0.05). In 92 per cent of thepatients without infective endocarditis and 76 per cent of those with infective endocarditis peak circulating immune complex levels developed within 14 days after their entry into the study, often on the initial sampling. In febrile, septicemic patients with clinical syndromes nonclassic for endocarditis, measurements of serial circulating immune complex levels may be of adjunctive diagnostic importance. If circulating immune complex levels are undetectable, endocarditis would appear less likely; alternatively, levels above 100 to 200 μg/ml would suggest a valvular rather than nonvalvular septic focus. © 1978.