[Bacterial endocarditis : lack of diagnostic value of immunological investigations (author's transl)].

To evaluate the diagnostic help afforded by immune determinations in feverish valvular patients, we prospectively determined: total hemolytic complement, cryoglobulin, rheumatoid factor, circulating immune complexes and direct skin immunofluorescence. Twenty patients entered the study, twelve with bacterial endocarditis, six without any bacteremia and two septicemic patients without endocarditis. We detected at least one immune abnormality in 10/12 endocarditis patients: - in 7/11 (64 p. cent) circulating immune complexes; - in 3/12 rheumatoid factor; - in 3/12 positive fluorescence in dermal vessels (IgM-C3); - and in one patient an IgG lupus-like band in the membrane basal zone. We also found circulating immune complexes in 3/4 patients without bacteremia and in 1/2 septicemic patients. We conclude that, in our small prospective study, immune abnormalities are frequent in bacterial endocarditis patients but their diagnostic values is rather limited : their absence do not rule out endocarditis and they can be present in many other febrile disorders.