[Aspecificity of the immunodiffusion reaction for the diagnosis of non-A non-B viral hepatitis].

A precipitating antigen-antibody system was detected by immunodiffusion using acute and convalescent sera from patients with non-A, non-B (NANB) viral hepatitis in which the diagnosis was made by exclusion. The system showed identity with reference sera. Positivity for antigen was found in 5 out 13 patients with acute NANB hepatitis, but also in 3 out 8 patients with acute A hepatitis, in 6 out of 15 with acute B hepatitis and in 95 out of 221 voluntary blood donors. Antibody was detected in all the above mentioned categories of patients and also in normal subjects in percentages ranging from 9.1 to 25.0 percent. The lack of specificity observed is in contrast with results of other reported serological NANB related systems.