T regulatory cells in cord blood--FOXP3 demethylation as reliable quantitative marker.
BACKGROUND
Regulatory T-cells (Tregs), characterized as CD4+CD25(hi) T-cells expressing FOXP3, play a crucial role in controlling healthy immune development during early immune maturation. Recently, FOXP3 demethylation was suggested to be a novel marker for natural Tregs in adults. In cord blood, the role and function of Tregs and its demethylation is poorly understood. We assessed FOXP3 demethylation in cord blood in relation to previously used Treg markers such as CD4+CD25(hi), FOXP3 mRNA, protein expression, and suppressive Treg function.


METHODS
Cord blood mononuclear cells (CBMC) were isolated from 70 healthy neonates, stimulated for 3 days with the microbial stimulus lipid A (LpA), and allergen Dermatophagoides pteronyssinus (Derp1). Tregs (CD4+CD25(hi), intracellular, mRNA FOXP3 expression, isolated cells), DNA methylation of the FOXP3-locus and suppressive Treg function were assessed.


RESULTS
Demethylation of FOXP3 in whole blood was specific for isolated CD4+CD25(hi) Tregs. Demethylation of FOXP3 was positively correlated with unstimulated and LpA-stimulated FOXP3 mRNA-expression (p≤0.05), and CD4+CD25(hi) T-cells (p≤0.03). Importantly, increased FOXP3 demethylation correlated with more efficient suppressive capacity of Tregs (r = 0.72, p = 0.005). Furthermore, FOXP3 demethylation was positively correlated with Th2 cytokines (IL-5, IL-13) following LpA-stimulation (p = 0.006/0.04), with Th2 and IL-17 following Derp1+LpA-stimulations (p≤0.009), but not Th1 cytokines (IFN-γ).


CONCLUSIONS
FOXP3 demethylation reliable quantifies Tregs in cord blood. FOXP3 demethylation corresponds well with the suppressive potential of Tregs. The resulting strict correlation with functionally suppressive Tregs and the relative ease of measurement render it into a valuable novel marker for large field studies assessing Tregs as qualitative marker indicative of functional activity.
Liu
Jing
J
Department of Pulmonary and Allergy, University Children's Hospital Munich, Ludwig-Maximilians-Universität Munich, Munich, Germany.
Lluis
Anna
A
Illi
Sabina
S
Layland
Laura
L
Olek
Sven
S
von Mutius
Erika
E
Schaub
Bianca
B
D015415:Biomarkers / Q000378:metabolism*; D002469:Cell Separation; D016207:Cytokines / Q000378:metabolism; D005312:Fetal Blood; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D057230:Limit of Detection; D008745:Methylation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
D015415:Biomarkers; D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors