Regulatory T-cell subset distribution in children with primary hypertension is associated with hypertension severity and hypertensive target organ damage.

Background: The relationship between circulating regulatory T-cell (Tregs) subset distribution and hypertension severity in children with primary hypertension is not known. We aimed to find out if target organ damage (TOD) in children with primary hypertension is related to defects in Tregs distribution reflected by their phenotype characteristics.

Methods: The study constituted 33 nontreated hypertensive children and 35 sex-matched and age-matched controls. Using multicolor flow cytometry technique, we assessed a distribution of the total Tregs (CD4CD25CD127) and their subsets (CD45RA-naive Tregs, CD45RA memory/activated Tregs, CD45RACD31 recent thymic emigrants Tregs and mature naive CD45RACD31 Tregs) in the whole blood.

Results: Hypertensive children showed decreased percentage of the total Tregs, the CD45RA-naive Tregs, the total CD31 Tregs and the recent thymic emigrants Tregs but elevation of the CD45RA memory/activated Treg and mature naive CD45RACD31 Tregs. Decreased frequency of the total Tregs, naive Tregs and CD31-bearing Treg cell subsets (CD31 total Tregs, CD45RACD31 recent thymic emigrants Tregs) negatively correlated to TOD markers, arterial stiffness and blood pressure elevation. In contrast, increased percentage of memory Tregs and CD31 Tregs subsets positively correlated to organ damage markers, arterial stiffness and blood pressure values. These changes were independent of BMI, age, sex and hsCRP.

Conclusion: Both diagnosis of hypertension, TOD and arterial stiffness in hypertensive children were associated with decreased population of total CD4 Tregs, limited output of recent thymic emigrants Tregs, and increased pool of activated/memory Tregs. Hypertension was an independent predictor of the circulating Treg subsets distribution irrespective of hsCRP.