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.Funding Agencies|FORSS (Medical Research Council of Southeast Sweden); Futurum, academy for Health and Care Jonkoping County Council, Sweden</p

Analysis of human lung mast cells by single cell RNA sequencing

Mast cells are tissue-resident cells playing major roles in homeostasis and disease conditions. Lung mast cells are particularly important in airway inflammatory diseases such as asthma. Human mast cells are classically divided into the subsets MCT and MCTC, where MCT express the mast cell protease tryptase and MCTC in addition express chymase, carboxypeptidase A3 (CPA3) and cathepsin G. Apart from the disctintion of the MCT and MCTC subsets, little is known about the heterogeniety of human lung mast cells and a deep analysis of their heterogeniety has previously not been performed. We therefore performed single cell RNA sequencing on sorted human lung mast cells using SmartSeq2. The mast cells showed high expression of classical mast cell markers. The expression of several individual genes varied considerably among the cells, however, no subpopulations were detected by unbiased clustering. Variable genes included the protease-encoding transcripts CMA1 (chymase) and CTSG (cathepsin G). Human lung mast cells are predominantly of the MCT subset and consistent with this, the expression of CMA1 was only detectable in a small proportion of the cells, and correlated moderately to CTSG. However, in contrast to established data for the protein, CPA3 mRNA was high in all cells and the correlation of CPA3 to CMA1 was weak

Guidelines for the use of flow cytometry and cell sorting in immunological studies

International audienceThe classical model of hematopoiesis established in the mouse postulates that lymphoid cells originate from a founder population of common lymphoid progenitors. Here, using a modeling approach in humanized mice, we showed that human lymphoid development stemmed from distinct populations of CD127(-) and CD127(+) early lymphoid progenitors (ELPs). Combining molecular analyses with in vitro and in vivo functional assays, we demonstrated that CD127(-) and CD127(+) ELPs emerged independently from lympho-mono-dendritic progenitors, responded differently to Notch1 signals, underwent divergent modes of lineage restriction, and displayed both common and specific differentiation potentials. Whereas CD127(-) ELPs comprised precursors of T cells, marginal zone B cells, and natural killer (NK) and innate lymphoid cells (ILCs), CD127(+) ELPs supported production of all NK cell, ILC, and B cell populations but lacked T potential. On the basis of these results, we propose a "two-family" model of human lymphoid development that differs from the prevailing model of hematopoiesis