[Immunofluorescence on Crithidia luciliae in the detection of anti-native DNA antibodies (author's transl)].

Antibodies to double-stranded (native) DNA were detected in 886 sera by indirect immunofluorescence (IF) using Crithidia luciliae (CL) as substrate. Comparison with 208 sera tested by Farr's method showed that the IF-on-CL method was more sensitive and at least as specific to native DNA. Anti-native DNA antibodies were mostly found in patients with systemic lupus erythematosus. Complement-binding antibodies of this kind were detected in sera with high titres (greater than or equal to 1/100) of antibodies belonging to the G, A and M groups of immunoglobulins. The IF-on-CL test is easier, cheaper, at least as specific and probably more sensitive than radioimmunoassays. It makes it possible to identify the Ig group to which the anti-native DNA antibodies belong and their ability to bind the complement. It deserves to be used as routine test for the detection of these antibodies and for their repeated titration in the follow-up of patients with systemic lupus erythematosus.