Linköping University

About: Linköping University is a education organization based out in Linköping, Sweden. It is known for research contribution in the topics: Population & Health care. The organization has 15671 authors who have published 50013 publications receiving 1542189 citations.

Analysis of the pilot contamination effect in very large multicell multiuser MIMO systems for physical channel models

Abstract: We consider multicell multiuser MIMO systems with a very large number of antennas at the base station. We assume that the channel is estimated by using uplink training sequences, and we consider a physical channel model where the angular domain is separated into a finite number of directions. We analyze the so-called pilot contamination effect discovered in previous work, and show that this effect persists under the finite-dimensional channel model that we consider. We further derive closed-form bounds on the achievable rate of uplink data transmission with maximum-ratio combining, for a finite and an infinite number of base station antennas.

FOXP3+ Regulatory T Cells and T Helper 1, T Helper 2, and T Helper 17 Cells in Human Early Pregnancy Decidua

Abstract: In pregnancy, the decidua is infiltrated by leukocytes promoting fetal development without causing immunological rejection. Murine regulatory T (Treg) cells are known to be important immune regulators at this site. The aim of the study was to characterize the phenotype and origin of Treg cells and determine the quantitative relationship between Treg, T-helper type 1 (T H 1), T H 2, and T H 17 cells in first-trimester human decidua. Blood and decidual CD4 + T cells from 18 healthy firsttrimester pregnant women were analyzed for expression of Tregcell markers (CD25, FOXP3, CD127, CTLA4, and human leukocyte antigen-DR [HLA-DR]), chemokine receptors (CCR4, CCR6, and CXCR3), and the proliferation antigen MKI67 by sixcolor flow cytometry. Treg cells were significantly enriched in decidua and displayed a more homogenous suppressive phenotype with more frequent expression of FOXP3, HLA-DR, and CTLA4 than in blood. More decidual Treg cells expressed MKI67, possibly explaining their enrichment at the fetal-maternal interface. Using chemokine receptor expression profiles of CCR4, CCR6, and CXCR3 as markers for T H 1, T H 2, and T H 17 cells, we showed that T H 17 cells were nearly absent in decidua, whereas T H 2-cell frequencies were similar in blood and decidua. CCR6 + T H 1 cells, reported to secrete high levels of interferon gamma (IFNG), were fewer, whereas the moderately IFNGsecreting CCR6 � T H 1 cells were more frequent in decidua compared with blood. Our results point toward local expansion of Treg cells and low occurrence of T H 17 cells. Furthermore, local, moderate T H 1 activity seems to be a part of normal early pregnancy, consistent with a mild inflammatory environment controlled by Treg cells. decidua, FOXP3, immunology, implantation, pregnancy