A simple method for demonstrating gel-precipitating human anti-immunoglobulin antibodies

The use of aggregated human IgG for the detection of anti-immunoglobulin antibodies by double immunodiffusion in gel is described. Of rheumatoid arthritis sera, 54 of 56 sera having a Waaler-Rose test titre of greater than or equal to 1:16 contained antibodies to aggregated IgG, in contrast to only 2 of 52 sera from blood donors. Furthermore, after 2-mercapto-ethanol treatment anti-IgG was still demonstrated in 5 of 16 sera.