title: T-Cell Depletion in the Colonic Mucosa of Patients With Idiopathic CD4+ Lymphopenia.
abstract: Idiopathic CD4(+) lymphopenia (ICL) is a rare syndrome characterized by low peripheral CD4(+) T-cell counts that can lead to serious opportunistic infections. The pathogenesis of ICL remains unclear, and whether effector sites are also lymphopenic is unknown. In this study, rectosigmoid mucosal biopsy specimens from patients with ICL and healthy controls were evaluated. Significant T-cell lymphopenia was observed in the mucosal tissue of patients with ICL by flow cytometry and immunohistochemistry, compared with healthy controls. Functional capacity of T cells, assessed by production of interferon γ and interleukin 17, was preserved in the mucosa of patients with ICL. In contrast to T lymphocytes, the frequency of myeloid cells (neutrophils and macrophages) was elevated in the colonic mucosa of patients with ICL. Despite the observed mucosal abnormalities, plasma levels of intestinal fatty acid binding protein, a marker of enterocyte turnover and other inflammatory biomarkers, including interleukin 6, C-reactive protein, and tumor necrosis factor, were not elevated in patients with ICL, compared with healthy controls, whereas soluble CD14 levels were minimally elevated. These data suggest that patients with ICL, despite gut mucosal lymphopenia and local tissue inflammation, have preserved enterocyte turnover and T-helper type 17 cells with minimal systemic inflammation. These observations highlight differences from patients with human immunodeficiency virus infection, with or without AIDS, and may partially explain their distinct clinical prognosis.
authors.affiliation: Clinical Research Directorate/Clinical Monitoring Research Program.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kovacs
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: Virginia
authors.initials: V
authors.lastname: Sheikh
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: William L
authors.initials: WL
authors.lastname: Thompson
authors.affiliation: Retroviral Immunopathology Section, AIDS and Cancer Virus Program.
authors.forename: David R
authors.initials: DR
authors.lastname: Morcock
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: Ainhoa
authors.initials: A
authors.lastname: Perez-Diez
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Yao
authors.affiliation: AIDS Monitoring Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research.
authors.forename: Adam W
authors.initials: AW
authors.lastname: Rupert
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, Galveston.
authors.forename: Netanya S
authors.initials: NS
authors.lastname: Utay
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: Gregg
authors.initials: G
authors.lastname: Roby
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: Alexandra F
authors.initials: AF
authors.lastname: Freeman
authors.affiliation: Retroviral Immunopathology Section, AIDS and Cancer Virus Program.
authors.forename: Jacob D
authors.initials: JD
authors.lastname: Estes
authors.affiliation: National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
authors.forename: Irini
authors.initials: I
authors.lastname: Sereti
mesh_terms: D000328:Adult; D001706:Biopsy; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003106:Colon / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007108:Immune Tolerance; D007150:Immunohistochemistry; D007249:Inflammation; D007413:Intestinal Mucosa / Q000473:pathology*; D008231:Lymphopenia / Q000473:pathology*; D008297:Male; D008875:Middle Aged
keywords: HIV/AIDS; biomarkers; idiopathic CD4+ lymphopenia; inflammation; mucosal immunity