الفهرس 
Aim of the workOnly 14 pages are availabe for public view
 |  | from | 118 |  |  |
| | | from | 118 | | |
Abstract
Summary
Antistreptolysin O (ASO) titer is a blood test to measure antibodies against strepolysin O, a substance produced by group A Streptococcus bacteria.
ASO particularly useful for the diagnosis of acute rheumatic fever and acute poststreptococcal glomerulonephritis. Acute rheumatic fever is an autoimmune disease that follows infection with Group A Streptococci (GAS); however, the isolation of GAS is uncommon (< 15%), and so confirmation of the diagnosis often relies on streptococcal antibody tests.
Streptococcal titers vary according to a number of factors, including age and population. In developed countries, where impetigo caused by GAS is uncommon, streptococcal titers in the population primarily reflect the incidence of pharyngeal infection with GAS; therefore, the titers in healthy people are low in early childhood, rise to a peak in children aged 5 to 15 yeras, decrease in late adolescence and early adulthood, and hen flatten off after that.
Because of these differences in titers ith age, it is recommended that age-stratified upper-limit-of-normal values be determined for populations of interest by testing people who have not had a recent streptococcal infection.
Age-stratified upper-limit-of-normal reference values have been defined for the US pediatric population, the Australian pediatric population, and the Indian pediatric population, among others.
However, there has been no investigations of upper-limit-of-normal values for populations in the Pacific region, where some of the highest rates of acute rheumatic fever and acute poststreptococcal glomerulonephritis are known to occur and where impetigo is common in children.
For studies that determine streptococcal serology reference ranges, it is important that a representative group of individuals without a known recent streptococcal infection be sampled. The immune response to GAS infections should be considered in determining which subjects should be excluded from analysis.
The ASO titer tends to rise a week following infection, peaks at 3 to 5 weeks, and begins to decline after 8 weeks; and it respnds more vigorously to pharyngeal infection than skin infection. The Anti-DNase B (ADB) titer peaks at 6 to 8 weeks after infection and begins to decline at 12 weeks, and it responds vigorously to both pharyngeal and skin infections. Therefore, subjects with recent pharyngitis or skin infections should not be included in the sample. The exclusion of children with GAS throat carriage is not necessary, as all healthy pediatric populations include carriers of GAS.
The aim of this study was to determine upper limit of normal range of antistreptolysin O titer in normal school children from 6-15 years old in Qalubyia Governorate.
This cross-sectional study was carried out in Qalubiya Governorate and the collected sample was tested in Clinical Pathology Laboratory at Benha University Hospitals in the period from July 2012 to January 2013.
Two hundred and fifty children aged 6-15 years participated in this study after consent from their parents. This systemic random sample was taken from Outpatient Clinic in Benha University Hospitals from cases coming for causes other than infection.
All children are subjected to: full medical history, full clinical examination (chest, cardiac, abdominal, throat and skin examinations) and investigations (including ASO, CRP, ESR and echocardiogram).
Our results showed that there is no significant difference between age and sex in the studied group. Children were categorized into two groups. Group- I included 151 children in the age group of 5-10 years constituting 60.4%. Group II include 99 children in the age group of 11-15 years constituting 39.6% for determination of age related ASO titer.
Our results showed also that:
• There is a high significant correlation of social class and residence of studied group.
• There is a high significant correlation between number of attacks of acute follicular tonsillitis and ASO titer level, age groups and social classes.
Conclusion and Recommendations
We concluded that the ULN ASOT in normal Egyptian children is quite high, reaching up to 398.5 IU/ml.
At screening of ASO we must put in our mind that the basal level of it increases with increasing number of attacks of acute follicolar tonsilitis and does not depend on social class.
Therefore, an isolated high ASOT is not sufficient to diagnose ARF. Basal levels of ASOT increase with age but age does not affect the peak level during acute streptococcal infection.
Additional studies will be required for establishment of standard values to avoid over diagnosis of ARF and comlpication of long acting penicilin.