[Comparison of 4 methods (immunofluorescence of antinuclear antibodies, indirect hemagglutination, immunodiffusion, counterimmunoelectrophoresis) for the differentiation and identification of nuclear antigen].

The performance of four methods (immunofluorescence of antinucleic antibodies (ANA), indirect haemagglutination, immunodiffusion and counterimmunoelectrophoresis) in the detection and differentiation of the antibodies against extractable nucleic antigen (ENA) was analysed with the aid of sera from 197 patients suffering from inflammatory diseases. Counterimmunoelectrophoresis showed the highest sensitivity and specificity for the detection and differentiation of antibodies against ribonucleoproteins (RNP), nuclear glycoprotein (Sm) and antibodies, which occur in Sicca (Sjögren) syndrome (SS-B, Ha). This method, like immunodiffusion, is suitable for demonstrating the common immunological identity of the ENA-antibody sera and the reference sera. The proof of immunological identity using the counterimmunoelectrophoresis was performed with the newly developed test system (pool procedure). This method, as compared to the procedure of Kurata & Tan ((1976) Arthritis Rheum. 19, 574-580) has certain technical advantages, and gives better identification.