FIGURE 1.

Telomerase deficiency results in decreased eosinophils, hematopoietic stem, and proliferating cells in the bone marrow and diminished serum IgE and IL13 levels and circulating eosinophils after HDM‐induced allergy. a‐b, Generation of Tert ^+/+ and G3 Tert ^−/− mice and protocol for chronic exposure to house dust mite (HDM). a, Heterozygous Tert ^+/− mice were crossed to obtain Tert ^+/+ and G1 Tert ^−/− mice, and successive crosses between G1 Tert ^−/− and then G2 Tert ^−/− were set to generate G3 Tert ^−/− mice. b, Eight‐ to 10‐week‐old female Tert ^+/+ and G3 Tert ^−/− mice were challenged by intranasal administration of 20 μg of house dust mite (HDM) extract in 20 μl of phosphate‐buffered saline (PBS) (1 mg/ml) or equal volume of PBS under inhaled isoflurane anesthesia, five days a week during four weeks. Lung function assessment and blood, bone marrow (BM), BALF, and lungs were collected 24 h after the last exposure to HDM on day (D) 28. c, Representative images showing cytospin preparations (May‐Grünwald Giemsa (MGG) (orange arrowheads indicate eosinophils)) (left) and immunostainings for CD34⁺ hematopoietic stem cells (brown) (red arrowheads) (center) and Ki67⁺ proliferating cells (brown) (right) in bone marrow sections from Tert ^+/+ and G3 Tert ^−/− mice. Quantification of total cells (d), eosinophis (e), neutrophils (f), CD34⁺ hematopoietic stem cells (g) and Ki67⁺ proliferating cells (h) in bone marrow sections from Tert ^+/+ and G3 Tert ^−/− mice. Quantification of total white blood cells (i), eosinophils (j), neutrophils (k), lymphocytes (l), and macrophages (m) in peripheral blood, and Total IgE (n), Total IgG (o) and IL13 (p) levels in serum from Tert ^+/+ and G3 Tert ^−/− mice. Quantifications in bone marrow cytospins and sections were evaluated in 4 different fields in a random way. Data are expressed as mean ±SEM. *p < 0.05; **p < 0.01; ***p < 0.001 (Dunn–Sidak multiple comparison test). The number of mice is indicated in each case