[Circulating immuns complexes and infections endocarditis. 64 cases (author's transl)].

An immunological study, with examination for circulating immune complexes (CIC) by precipitation by polyethylene-glycol (PEG) and by fixation of labelled C1q, was carried out in 64 patients with infectious endocarditis (IE). One or more complementary studies during the course of the illness were possible in 23. CIC were found in 84 p. 100 of cases (66 p. 100 of acute IE and 89 p. 100 of subacute IE), during the active phase of the disease. High levels of PEG precipitate were correlated with typical cutaneous signs (including Osler's nodes), with the presence of cryoglobulins. With effective antibiotic treatment, the level of PEG precipitate (17 patients) returned to normal within one month, in parallel with a fall in rheumatoid factor and in cryoglobulins. By contrast, ineffective treatment was invariably reflected (6 patients) by a rise in levels of PEG precipitate. The estimation of CIC using the PEG technique during IE would already appear to be a value aid in cases of difficult diagnosis, and a research area worthy of further exploration within the context of IE.