[Antinuclear antibodies in diagnosis of rheumatic diseases (author's transl)]

Hundred ana-positive sera--60 sera of SLE-patients and 40 sera of patients suffering from rheumatoid arthritis--were investigated for ana and DNA-antibodies. For these purposes nine different methods including several radioimmunological and immunofluorescence techniques with partially distinct antigen-specificities were tested. While the radioimmunoassays showed only slightly different results, significant differences in sensitivity as well as in antibody specificity existed mainly in the indirect immunofluorescence techniques using different substrates. For clinical use, a combination of various techniques seemed to be useful i.e. indirect immunofluorescence on hemolysed bird erythrocytes and on frozen native rat liver sections. For DNA-antibodies in diagnosis and control during the course of the diseases the radioimmunoassay with simultaneous detection of antibodies to single- and double stranded DNA is most suitable. Antibodies to distinct nuclear antigens are detectable in various amount in the rheumatic diseases. While ds-DNA-antibodies seemed to be most specific for SLE, ss-DNA-antibodies occurred in nearly all ana-positive sera and seemed to be less specific for one disease than all the other ana-fractions.