Background and Aims:
Sickle cell disease (SCD) is a chronic hemolytic anemia that may be life-threatening due to multisystemic effects. Identification of the factors which affect the pathophysiology of the disease is important in reducing mortality and morbidity. This study aimed to determine gut microbial diversity in children and adolescents with SCA compared with healthy volunteers and to evaluate the clinical impact of microbiota.

Materials and Methods:
The study included 34 children and young adolescents with SCD and 41 healthy volunteer participants. The microbiome was assessed by 16S rRNA sequencing in stool samples. Laboratory parameters of all participants, such as complete blood count and C-reactive protein values and clinical characteristics of SCD patients, were determined and compared, as well as clinical conditions of the patients, such as vascular occlusive crisis and/or acute chest syndrome, frequency of transfusions, intake of penicillin, hydroxyurea, and chelation therapy were recorded.

Results:
White blood cell count, hemoglobin, immature granulocyte and C-reactive protein levels were significantly higher in the patient group (P<0.05). Microbiota analysis revealed 3 different clusters among subjects; controls and 2 clusters in the SCD patients (patient G1 and G2 groups). Bacteroides spp. were more prevalent, while Dialester spp. and Prevotella spp. were less prevalent in SCD compared with controls (t=2.142, P<0.05). Patient G2 (n=9) had a higher prevalence of Bacteroides and a lower prevalence of Prevotella than patient G1 (n=25).

Conclusion:
In our study, there was a difference between SCD patients and the control group, while 2 different microbiota profiles were encountered in SCD patients. This difference between the microbiota of the patients was not found to affect the clinical picture (such as vascular occlusive crisis, acute chest syndrome).