Identification of specific antibodies to extractable nuclear antigens by passive immunodiffusion

Extractable nuclear antigens have been identified in a number of systemic rheumatic diseases and may be useful in differentiating those with overlapping clinical features. A number of detection systems have been described but technical feasibility and sensitivity have limited widespread application. We describe a simple immunodiffusion method to identify extractable nuclear antigens with high specificity and sensitivity that compares favorably with parallel hemagglutination studies. This method can be applied easily to routine analysis of antinuclear antigens.