Anti-Deoxyribonuclease B (anti-DNase B) titres are a quantitative measure of the presence of serologic

antibodies An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...

obtained from patients suspected of having a recent group A (Beta-hemolytic)

streptococcus ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...

bacteria infection, from ''

Streptococcus pyogenes ''Streptococcus pyogenes'' is a species of Gram-positive, aerotolerant bacteria in the genus ''Streptococcus''. These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains. They are ...

''. In a patient with suspected post-streptococcal

glomerulonephritis Glomerulonephritis (GN) is a term used to refer to several kidney diseases (usually affecting both kidneys). Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the ...

, anti-streptolysin-O titres (ASOTs) can be negative even after strep

pharyngitis Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice ...

. Some studies suggest that up to 85% of patients with

acute rheumatic fever Rheumatic fever (RF) is an inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a streptococcal throat infection. Signs and symptoms include fever, multiple painful jo ...

from group A strep infection will be positive for ASO titers, leaving 15% of patients having been diagnosed with rheumatic fever negative for ASO titers. In addition and contrary to percentages seen in strep pharyngitis, strep skin infection induces ASO antibodies less often, which can be problematic for physicians searching for a cause of the glomerulonephritis and having a high suspicion that its etiology was strep. Post-streptococcus glomerulonephritis is more often associated with group A strep skin infection than it is with strep pharyngitis, so in a patient with suspected post-strep glomerulonephritis with a negative ASO titer, one can then obtain anti-DNase-B titers which are more sensitive for group A strep and for its various strains. Anti-DNase B antibody titers also stay elevated for longer, which is useful since often ASO titers may rise, but then fall prior to the onset of the glomerulonephritis where the onset of disease is often greater than 2 weeks after the infection resolved. In this way anti-DNase B titers are very useful to clinicians and allow for evidence of the recent infection to be seen and levels of this antibody to be quantified.Arch Dis Child. 2001 Sep;85(3):223-7. Rheumatic fever in a high incidence population: the importance of monoarthritis and low grade fever. Carapetis JR1, Currie BJ.

References

Antibodies Infectious disease blood tests {{portal bar, Biology