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Antistreptolysin O in serum
Last reviewed: 23.04.2024
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Reference values of antistreptolysin O (ASLO) in the blood serum: adults - less than 200 IU / ml, children - up to 150 IU / ml.
Infections caused by group A streptococcus always cause a specific immune response - a significant increase in the antibody titer to at least one of the extracellular streptococcal antigens - streptolysin O, deoxyribonuclease B, hyaluronidase or nicotinamide-adenine dinucleotidase.
ASLO - antibodies against streptococcal hemolysin. A. ASLO is a marker of acute streptococcal infection. The concentration of ASLO rises in the acute period of infection (7-14 days) and decreases during convalescence and recovery. In clinical practice, the use of ASO is used to monitor the dynamics of the rheumatic process. The titer of ASLO is increased in 80-85% of patients with rheumatic fever. Diagnostic value has a persistent significant increase in ASLO activity. By the third week of the disease with rheumatism, the titer rises significantly, reaching a maximum by the 6th-7th week. With a favorable course of the process, by the 4th-8th month, the concentration of ASLO is reduced to the norm. Under the influence of the therapy, these terms can be reduced. The absence of a decrease in the ASLO concentration by the 6th month of the disease suggests the possibility of relapse. A persistent and prolonged increase in activity after angina may be a harbinger of the rheumatic process. In 10-15% of cases of rheumatic fever, an increase in the concentration of ASOs is not determined.
Increased ASLO is found in some patients with rheumatoid arthritis, but the level of its increase with this disease is lower than with rheumatism. When the β-hemolytic streptococci of group A are isolated, elevated levels of ASLO are detected in 40-50% of bacterial carriers.
The increase in the TSO titers is found in half of patients with acute glomerulonephritis developing after streptococcal infection.
In most cases, acute rheumatism or acute post-streptococcal glomerulonephritis develops between 1 week and 1 month from the onset of infection; the average latency period is 18 days for rheumatism, 12 days for glomerulonephritis after infection of the pharynx and up to 2-3 weeks after skin infections. Therefore, it is most likely to detect an increase in the concentration of ASLO and other antibodies in the first 2-3 weeks from the onset of the disease.
Skin streptococcal infections often cause weak ASLO production, probably due to the inhibitory effect on ASO-XC and a number of skin-related lipids.
It should always be remembered that taking antibiotics in the acute phase of streptococcal infection significantly reduces the severity of the immune response, and an increase in the concentration of ASOs can be negligible.
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