P053 The place of ASLOs in the diagnosis of RAA in Morocco
Authors: Sara Himri , Bouchra Oumokhtar , Samira El Fakir , Samir Atmani 
Published: November 2021

Abstract

Background
The assay of antistreptolysin O antibodies “ASLO” can provide evidence of infection of streptococcal origin, but it cannot confirm the presence of rheumatic fever “RAA” or the degree of severity of the disease. However, it is widely prescribed in daily practice by pediatricians and general practitioners to diagnose RAA. Unfortunately, the only finding of a high rate of ASLO in front of recurrent tonsillitis in children is considered by some practitioners as sufficient evidence to support the diagnosis of RAA, especially in its minor form, without taking into account the Jones criteria. The objective of this study is to put the ASLO assay in its place in the diagnosis of RAA in children in the region of Fez in Morocco.

Methods
This is a prospective study carried out from January 2016 to July 2019 in the cardiopediatric unit of CHU Hassan II in Fez. Patients below 18 years of age were included in this study. The children are classified into 4 groups: group 1: RAA with cardiac involvement, group 2: RAA without cardiac involvement, group 3: recurrent pharyngitis and group 4: control. Children with RAA are diagnosed according to the modified Jones criteria. The repetitive angina group includes any child who has tonsillitis &gt;5 times a year. The control group presents healthy children. The ASLO assay was carried out in the central analysis laboratory of the CHU Hassan II in Fez. Patient data is collected on operating sheets. Statistical analysis was performed using SPSS v 21 software.

Results
These are 153 children with RAA: 119 cases of RAA with cardiac involvement and 34 cases of RAA without cardiac involvement, 86 children with recurrent pharyngitis and 157 children controls. The most common age group in the four groups is the age group between 5 and 15 years old. The frequency of children of urban origin is greater than that of rural origin in all the groups studied. The average ASLO rates in each group are as follows:
RAA with carditis: 281.1 IU/ml
RAA without carditis: 331.9 IU/ml
Repeated angina: 397.7 IU/ml
Control: 208.8 IU/ml
Monitoring the change in ASLO, every 3 months for a year, in the groups studied showed that the ASLO level is stable at high rates in the case of recurrent pharyngitis and it tends to decrease in the case of AAR. Regarding the relationship between ASLO means and gender, there is a high ASLO mean in boys more than girls in all groups. Also, the mean ASLO is high in children from urban areas for the recurrent angina group. In addition, the average rate of ASLO is high during cold seasons in all groups. Finally, our study shows that the increase in ASLO is related to age. There is a significant difference between ASLO rates and age in all groups.

Conclusion
ASLO levels do not correlate with cardiac involvement but rather with infection and the child's individual immunity. The evidence is that ASLO levels&gt; 200 IU/ml are more common with recurrent pharyngitis than with rheumatic heart disease. So a high ASLO is not necessarily related to an RAA.

Keywords
ASLO, children, RAA, recurrent tonsillitis