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P. Christine Nguyen, MD

  • Phuong Christine Nguyen

Specialties

Gastroenterology/Nutrition/Hepatology

Gastroenterology

Work and Education

Professional Education

UT Southwestern Medical School, Dallas, TX, 2000

Internship

Georgetown University Hospital, Washington, DC, 2001

Residency

Georgetown University Hospital, Washington, DC, 2003

Fellowship

Stanford University Medical Center, Stanford, CA, 2006

Board Certifications

Pediatric Gastroenterology, American Board of Pediatrics

Pediatrics, American Board of Pediatrics

All Publications

Increased Number of Regulatory T Cells in Children With Eosinophilic Esophagitis JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Fuentebella, J., Patel, A., Nguyen, T., Sanjanwala, B., Berquist, W., Kerner, J. A., Bass, D., Cox, K., Hurwitz, M., Huang, J., Nguyen, C., Quiros, J. a., Nadeau, K. 2010; 51 (3): 283-289

Abstract

There are limited data on the role of regulatory T cells (Treg) in the disease pathology of eosinophilic esophagitis (EoE). We tested the differences in Treg in subjects with EoE compared with those with gastroesophageal reflux disease (GERD) and healthy controls (HC).Pediatric patients evaluated by endoscopy were recruited for our study. Participants were categorized into 3 groups: EoE, GERD, and HC. RNA purified from esophageal biopsies were used for real-time quantitative polymerase chain reaction assays and tested for forkhead box P3 (FoxP3) mRNA expression. Treg were identified as CD4+CD25hiCD127lo cells in peripheral blood and as CD3+/FoxP3+cells in esophageal tissue.Forty-eight subjects were analyzed by real-time quantitative polymerase chain reaction: EoE (n = 33), GERD (n = 7), and HC (n = 8). FoxP3 expression was higher by up to 1.5-fold in the EoE group compared with the GERD and HC groups (P < 0.05). Protein levels of FoxP3 in blood and tissue were then investigated in 21 subjects: EoE (n = 10), GERD (n = 6), and HC (n = 5). The percentage of Treg and their subsets in peripheral blood were not significant between groups (P > 0.05). The amount of Treg in esophageal tissue was significantly greater in the EoE group (mean 10.7 CD3+/FoxP3+cells/high power field [HPF]) compared with the other groups (GERD, mean 1.7 CD3+/FoxP3+cells/HPF and HC, mean 1.6 CD3+/FoxP3+cells/HPF) (P < 0.05).We show that Treg are increased in esophageal tissue of EoE subjects compared with GERD and HC subjects. The present study illustrates another possible mechanism involved in EoE that implicates impairment of immune homeostasis.

View details for DOI 10.1097/MPG.0b013e3181e0817b

View details for Web of Science ID 000281453500007

View details for PubMedID 20639775

Decreases in circulating CD4(+)CD25(hi)FOXP3(+) cells and increases in intragraft FOXP3(+) cells accompany allograft rejection in pediatric liver allograft recipients PEDIATRIC TRANSPLANTATION Stenard, F., Nguyen, C., Cox, K., Kambham, N., Umetsu, D. T., Krams, S. M., Esquivel, C. O., Martinez, O. M. 2009; 13 (1): 70-80

Abstract

We examined CD4(+)CD25(hi)FOXP3(+) cells Treg in children following liver transplantation and determined the relationship between Treg cell levels in the blood and in the graft. Peripheral blood was obtained from pediatric liver transplant patients at sequential time points: pre-transplant, one month, 3-4 months, 6-7 months, and 11-12 months post-transplant. PBMC were isolated, labeled for CD4, CD25 and FOXP3 expression and analyzed by flow cytometry for CD4(+)CD25(hi)FOXP3(+) cells. Sorted CD4(+)CD25(hi) cells were assessed for functional activity. Pretransplant blood levels of CD4(+)CD25(hi)FOXP3(+) Treg cells were not significantly different from post-transplant blood levels of CD4(+)CD25(hi)FOXP3(+) Treg cells. However, the blood levels of CD4(+)CD25(hi)FOXP3(+) Treg cells were significantly decreased during acute rejection compared with levels when graft function was stable. Immunohistochemistry revealed that FOXP3(+) cells were increased in the portal region of livers with histopathologic evidence of acute graft rejection compared with livers without evidence of rejection and were localized primarily within the inflammatory infiltrate. These data indicate that Treg cells are found at the site of allograft rejection and may play a role in regulation of alloreactivity. Moreover, monitoring peripheral CD4(+)CD25(hi)FOXP3(+) Treg cell levels may be useful in improving the post-transplant management of pediatric liver allograft recipients.

View details for DOI 10.1111/j.1399-3046.2008.00917.x

View details for Web of Science ID 000262285400012

View details for PubMedID 18331536

Trifluoroacetylated IgG4 antibodies in a child with idiosyncratic acute liver failure after first exposure to halothane JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Nguyen, C., Rose, N. R., Njoku, D. B. 2008; 47 (2): 199-202

View details for Web of Science ID 000258009700015

View details for PubMedID 18664874

View details for PubMedCentralID PMC2746329

Cold agglutinin syndrome in pediatric liver transplant recipients PEDIATRIC TRANSPLANTATION Wong, W., Merker, J. D., Nguyen, C., Berquist, W., Jeng, M., Viele, M., Glader, B., Fontaine, M. J. 2007; 11 (8): 931-936

Abstract

Anemia is a common finding in post-liver transplant patients. Causes for the anemia include nutritional deficiencies, red cell aplasia as well as immune-mediated hemolysis. One of the immunologic causes of hemolytic anemia is drug-induced hemolysis. Tacrolimus is a common immunosuppressant used in post-liver transplant patients to prevent graft rejection. There have been reports of tacrolimus-associated hemolytic anemia secondary to hemolytic uremic syndrome as well as autoimmune hemolysis. There are also case-reports of severe hemolytic anemia related to cold agglutinin production in post-liver transplant patients. We described in this paper three cases of severe cold agglutinin hemolytic anemia in three pediatric liver transplant patients. Steroid therapy, plasmapheresis and withdrawal of tacrolimus led to resolution of the severe hemolytic process in each case. Whether the immune-mediated hemolysis is related to tacrolimus is not clear and needs to be characterized further.

View details for DOI 10.1111/j.1399-3046.2007.00795.x

View details for Web of Science ID 000250520100016

View details for PubMedID 17976131