Distal respiratory tract viral infections in young children trigger a marked increase in alveolar mast cells

Research output: Contribution to journalArticle

Abstract

Viral infections predispose to the development of childhood asthma, a disease associated with increased lung mast cells (MCs). This study investigated whether viral lower respiratory tract infections (LRTIs) can already evoke a MC response during childhood. Lung tissue from young children who died following LRTIs were processed for immunohistochemical identification of MCs. Children who died from nonrespiratory causes served as controls. MCs were examined in relation to sensitisation in infant mice exposed to allergen during influenza A infection. Increased numbers of MCs were observed in the alveolar parenchyma of children infected with LRTIs (median (range) 12.5 (0-78) MCs per mm2) compared to controls (0.63 (0-4) MCs per mm2, p=0.0005). The alveolar MC expansion was associated with a higher proportion of CD34+ tryptase+ progenitors (controls: 0% (0-1%); LRTIs: 0.9% (0-3%) CD34+ MCs (p=0.01)) and an increased expression of the vascular cell adhesion molecule (VCAM)-1 (controls: 0.2 (0.07-0.3); LRTIs: 0.3 (0.02-2) VCAM-1 per mm2 (p=0.04)). Similarly, infant mice infected with H1N1 alone or together with house dust mite (HDM) developed an increase in alveolar MCs (saline: 0.4 (0.3-0.5); HDM: 0.6 (0.4-0.9); H1N1: 1.4 (0.4-2.0); HDM+H1N1: 2.2 (1.2-4.4) MCs per mm2 (p<0.0001)). Alveolar MCs continued to increase and remained significantly higher into adulthood when exposed to H1N1+HDM (day 36: 2.2 (1.2-4.4); day 57: 4.6 (1.6-15) MCs per mm2 (p=0.01)) but not when infected with H1N1 alone. Our data demonstrate that distal viral infections in young children evoke a rapid accumulation of alveolar MCs. Apart from revealing a novel immune response to distal infections, our data may have important implications for the link between viral infections during early childhood and subsequent asthma development.

Details

Authors
Organisations
External organisations
  • University of São Paulo
  • McMaster University
  • United States Food and Drug Administration
  • MedImmune, Inc.
  • University of Oklahoma
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Microbiology in the medical area
  • Immunology in the medical area
Original languageEnglish
JournalERJ Open Research
Volume4
Issue number4
Publication statusPublished - 2018 Oct
Publication categoryResearch
Peer-reviewedYes