Regulatory T-cell Subpopulations in Severe or Early-onset Preeclampsia.

PROBLEM A deficiency in regulatory T (Treg) cells causing reduced immune regulatory capacity has been proposed in preeclampsia. OBJECTIVE Utilizing recent advances in flow cytometry phenotyping, we aimed to assess whether a deficiency of Treg subpopulations occurs in preeclampsia. METHOD OF STUDY Six-color flow cytometry was used for Treg phenotyping in 18 preeclamptic women (one early-onset, one severe and 16 both), 20 women with normal pregnancy, and 20 non-pregnant controls. RESULTS No differences were found in major Treg populations including CD127(low) CD25(+) /CD127(ow) FOXP3(+) , resting (FOXP3(dim) CD45RA(+) ), and activated (FOXP3(bright) CD45RA(-) ) Treg cells, whereas preeclamptic women showed increased CTLA-4(+) and CCR4(+) proportions within resting/activated Treg populations. Corticosteroid treatment prior to blood sampling (n = 10) affected the distribution of Treg populations. CONCLUSIONS Although we found no major alterations in circulating Treg frequencies, differences in CTLA-4(+) and CCR4(+) frequencies suggest a migratory defect of Treg cells in preeclampsia. Corticosteroid treatment should be taken into account when evaluating Treg cells.