Significance of anti-deoxyribonuclease-B (ADN-B) determination in clinical practice.

The determination of anti-deoxyribonuclease-B (ADN-B) is very important for the diagnosis of antecedent streptococcal infection because almost all of group A streptococci have this antigen and a strong elevation of the antibody is observed in patients with acute rheumatic fever, acute glomerulonephritis and other streptococcal infections. Moreover, ADN-B titers are elevated in cases with streptococcal skin infection, whereas anti-streptolysin O (ASO) titers are rarely elevated in these cases. So the determination of ADN-B is recommended as the second streptococcal antibody test to ASO detection (manual of WHO). In our study, the upper limits of ADN-B in normal subjects were 1:60 in preschool age, 1:480 in school age and 1:340 in adult age groups. In acute rheumatic fever, ADN-B titers were elevated in 87% of the cases and also 87% of the patients with acute glomerulonephritis had high ADN-B titers. In inactive rheumatic fever, 72% of the patients had high ADN-B titers, while, ASO titers were elevated in only 22% of the cases. In streptococcal carrier states, 39% of the children had high ADN-B titers but ADN-B was positive only 8% in non-carrier children.