Circulating immune complexes in Takayasu disease were investigated to assess the involvement of autoimmune mechanisms. Antibody dependent cell-mediated cytotoxicity (ADCC) and Raji cell assay revealed: The 10 percent inhibition of ADCC in 37 patients was 35.6 +/- 5.2, this being a non-statistically significant value as compared with the values of 25.6 +/- 3.0 in 33 apparently healthy controls. Raji cell assay values were 30.4 +/- 11.5 and 3.5 +/- 2.3 for patients and controls, respectively. As 54% of all these patients had a negative reaction and there was no correlation between immune complex levels and BSR, CRP, or ASO, immune complexes, while accelerating or modifying the pathophysiological state, probably are not primary causative factors.