Antibody assays for streptodornase B were done on a total of 58 patients with habitual angina together with assays for both blue ASO and anti SK·SD titers. The results are summarized as follows:
1) The antibody titer for streptodornase B ranged from 50 to 1, 600 times by means of the toluidine blue 0 method of Tiesler.
2) There was a low correlation between the antibody titer for streptodornase B and the blue ASO and anti SK·SD titers.
3) It was considered to be significant for diagnosis of streptococcal infection that antibody titers for streptodornase B were widely distributed in sera of patients with habitual angina.
