Background: Regulatory T cells (Tregs) are linked to a reduction in alloreactive immune responses, but few studies have investigated the impact of hydroxyurea (HU) therapy on Tregs in sickle cell disease (SCD).

Methods: Our case-controlled study presented here included two groups, the first comprising 60 pediatric SCD patients, 30 of whom did not receive any treatment and 30 who received HU, and the second group consisting of 30 healthy controls. Flow cytometry was used to evaluate the percentage of CD4⁺CD25^+highFoxp3⁺ Tregs present and their phenotypes.

Results: The percentage of CD4⁺CD25^+high Tregs was significantly increased in untreated SCD patients in comparison to treated SCD patients and controls. Conversely, treated SCD children had a lower percentage of CD4⁺CD25^+high Tregs than controls. Additionally, a significant increase in the percentage of CD4⁺CD25^+highFoxp3⁺ Tregs was found in untreated SCD patients, compared to in HU treated patients and controls. The percentage of naive CD45RA⁺ Tregs was significantly decreased in untreated SCD patients when compared to other groups.

Conclusion: Among children with SCD, HU treatment exhibited significant qualitative and quantitative effects on Tregs by decreasing their frequency and increasing the proportion of naive CD45RA⁺ Tregs and reducing levels of the most suppressive Tregs: HLA-DR⁺, CD39⁺, and CD69⁺.

Recent studies have attempted to measure several biomarkers to understand the complex interactions of the anatomic systems
that may be involved in autism spectrum disorder (ASD). In CNS, galanin takes part in a variety of pathological and physiological
processes. Prior research has indicated it is involved in several neuropsychiatric disorders and has a role in inhibiting
the neuronal firing and release of serotonin, norepinephrine, and acetylcholine. To date, serum galanin levels have not been
investigated in the context of ASD. This study aimed, therefore, to compare the serum galanin levels of children with ASD
and healthy controls and to reveal any association between galanin level and the severity of ASD, as well as other psychological
and demographic parameters. Serum galanin levels were measured by radioimmunoassay in 116 children with ASD
and 98 healthy children. We observed significantly increased serum concentrations of galanin in children with ASD relative
to healthy children. Moreover, children with severe ASD had significantly higher galanin levels than those with less severe
disease. We also confirmed significant positive correlations between galanin and psychiatric parameters in children with
ASD. For the first time, we suggest a possible correlation between serum galanin and the degree of ASD severity. Increased
galanin levels may play a role in the pathogenesis of ASD.