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Identification of Tr1 Cells in a Pediatric Population
Sunday, March 6, 2016: 3:00 PM
Room 406AB (Convention Center)
Jenna R. Bergerson, MD MPH, ,
Rationale: Regulatory T (Treg) cells play an important role in the maintenance of self-tolerance. Patients who lack these cells have an increased incidence of food allergies (FA). Tr1 cells are a subset of Treg cells that are peripherally induced and play a pivotal role in promoting and maintaining tolerance. Recent identification of surface markers that uniquely identify Tr1 cells (Lag3+ and CD49b+) were identified in a small number of healthy adult patients. However, they have not been identified in a pediatric population.

Methods:  Peripheral blood mononuclear cells were isolated from 10 pediatric patients recruited at the Ann & Robert H. Lurie Children’s Hospital of Chicago and analyzed using flow cytometry. Populations of thymically derived Treg cells (CD4+CD25+CD127-FoxP3+) and Tr1 cells (CD4+CD45RA-Lag3+CD49b+) were determined in children with and without FA.

Results: Percentages of CD4+CD25+CD127- expressing FoxP3+ were significantly higher (70.1 v 43, P=0.033) in healthy children compared to food allergic children. Although there was no difference in total CD4+CD45RA-CD49b+Lag3+ cells, percentages of CD4+CCR6+ cells expressing CD49b+Lag3+ cells were significantly higher (20.26 v. 5.91, p=0.033) in healthy children compared to food allergic children.

Conclusions:  Tr1 cells were detected in a pediatric population. Children without FA have a larger percentage of Treg cells (CD25+CD127-) expressing FoxP3+, possibly indicating these Treg cells may be more functional than those found in FA children. Children without FA have a larger percentage of gut-homing Tr1 cells (CCR6+CD49b+Lag3+), suggesting that gut-homing Tr1 cells may be important in maintaining oral tolerance.