TABLE 2

Mast cell (MC) densities in young children with lower respiratory tract infections compared to controls

FeatureControlsRSVADVInfluenza Ap-value
Total MCs
 Small airways# MCs per mm15 (4–36)20 (5–30)10 (3–41)34 (8–53)0.149
 Pulmonary vessels# MCs per mm6 (2–23)12 (3–19)6 (3–12)11 (3–44)0.523
 Alveolar parenchyma MCs per mm21 (0–13)28 (1–54)7 (1–50)13 (0–78)0.004
MCT    
 Small airways# MCs per mm14 (2–32)17 (4–23)6 (1–24)27 (5–34)0.054
 Pulmonary vessels# MCs per mm2 (0–6)6 (1–10)2 (0–6)5 (2–28)0.185
 Alveolar parenchyma MCs per mm21 (1–3)22 (1–41)4 (1–34)11 (0–58)0.004
MCTC    
 Small airways# MCs per mm1 (0–8)3 (0–7)5 (0–17)6 (2–20)0.099
 Pulmonary vessels# MCs per mm5 (1–19)6 (1–8)3 (2–7)6 (1–23)0.384
 Alveolar parenchyma MCs per mm20 (0–1)7 (0–13)3 (0–16)2 (0–20)0.009
Proportion of MCTC
 Small airways15% (2–80%)17% (12–23%)40% (0–69%)19% (12–42%)0.018
 Pulmonary vessels73% (50–100%)50% (45–88%)57% (33–97%)46% (33–77%)0.042
 Alveolar parenchyma0% (0–50%)23% (0–42%)33% (0–75%)14% (10–43%)0.398

Data are presented as median (range) unless otherwise stated. RSV: respiratory syncytial virus; ADV: adenovirus. #: MC number related to length of perimeter of reticular basement membrane. : MC numbers related to tissue area of alveolar parenchyma (including airspaces); for results where airspaces were excluded, see the supplementary material.