Deoxyribonuclease B (DNase B) Antibody

Group A streptococci produce several extracellular products including streptolysin O, hyaluronidase, streptokinase, desoxyribonucleases (DNAase A, B, C, D), and nicotinamide adenine dinucleotidase (NADase). Streptococcal infections can lead to serious complications of glomerulonephritis and rheumatic fever following a latency period of 10 to 20 days after the acute infection. Serologic detection of antibodies to these streptococcal antigens may provide evidence of previous streptococcal infection. 

Anti-streptolysin O (ASO) titers are elevated in about 85% of individuals with rheumatic fever. Streptococcal skin infections, in contrast to throat infections, are associated with a poor ASO response. Therefore, patients who develop acute glomerulonephritis following a skin infection may not  have a significant rise in ASO. In these instances, additional testing for anti-DNAse B is recommended.

Two prospective studies provided important insight into the immune response to Streptococcal infection over an extended period of time. One hundred and sixty randomly selected children between the ages of 6 and 15 years (mean 10 years) had monthly throat cultures and serum collections every 13 weeks for measurement of ASO and anti-DNase B titers during an average observation period of 97 weeks. Each participant had an average of 21.8 throat cultures and 10.5 antibody titers during the study. 

Approximately one third of the patients with Group A streptococcal infection had a positive throat culture and significant elevations of both ASO and ADB titers. In the remaining two thirds of cases, either ASO or anti-DNase B was elevated, but not both. Serological confirmation of infection would have been missed in 22% of cases if only one these antibodies had been ordered. 

Group A, group C and group G streptococci all produce antigenically identical ASO and all three stimulate the same magnitude of ASO response. In contrast anti-DNase B is more specific for GAS infection. No ADB responses were seen following infection with group C or group G Streptococcus. Another interesting finding was that antibiotic treatment did not significantly affect ASO and anti-DNase B antibody responses even though bacteria were eradicated.   

Anti-DNase B titers are measured by nephelometry. The reference range is age specific:

Specimen requirement is one plain red top or SST tube of blood.  SST tube needs to be centrifuged within 30 minutes of drawing and refrigerated.

References

Johnson DR et al. The Human Immune Response to Streptococcal Extracellular Antigens: Clinical, Diagnostic, and Potential Pathogenetic Implications, Clinical Infectious Diseases 2010;50(4):481-90.

Kaplan EL, et al. The influence of the site of infection on the immune response to group A streptococci. J Clin Invest. 1970 Jul; 49(7):1405-1414.