Interferon-γ Treatment of Human Laryngotracheal Stenosis-Derived Fibroblasts

IMPORTANCE Laryngotracheal stenosis (LTS) is a fibroproliferative disorder of the glottis, subglottis, and trachea. In models of fibrosis from other organ systems, the CD4(+) T-cell response has been shown to regulate extracellular matrix deposition. Specifically, helper T cell 2 (T(H)2) promotes fibrosis, whereas T(H)1 and associated cytokines have been shown to be antifibrotic. However, this antifibrotic effect of the T(H)1 response has not been demonstrated in LTS. OBJECTIVE To determine whether the T(H)1 cytokine interferon-gamma inhibits the function of LTS-derived fibroblasts in vitro. DESIGN, SETTING, AND PARTICIPANTS This in vitro controlled study included 6 patients with iatrogenic LTS undergoing routine surgical subglottic and tracheal dilation at a single institution. Fibroblasts were isolated from biopsy specimens of laryngotracheal scar and normal-appearing trachea. The presence of fibroblasts was confirmed by an immunohistochemical analysis. Laryngotracheal stenosis-derived fibroblasts were treated with interferon-gamma and compared with untreated controls (2 sets of untreated, LTS-derived fibroblasts [media did not contain interferon-gamma]) and normal airway fibroblasts (fibroblasts isolated from normal trachea). Data were collected from August 2015 through June 2016. INTERVENTIONS Treatment with interferon-gamma 10 ng/mL. MAIN OUTCOMES AND MEASURES Cellular proliferation, fibrosis gene expression (using quantitative reverse transcription polymerase chain reaction analysis), soluble collagen, and cellular histologic features were assessed. RESULTS Among the 6 patients (6 women; mean [SD] age, 38.3 [17.2] years), LTS-derived fibroblast proliferation was reduced in patients who received interferon-. treatment compared with untreated controls on days 3 (mean difference, -6515 cells; 95% CI, -10 630 to -2600 cells) to 6 (mean difference, -47 521 cells; 95% CI, -81 285 to -13 757 cells). Interferon-gamma treatment reduced collagen types I and III gene expression by 86% and 68%, respectively, and resulted in lower total collagen production (10.94 vs 14.89 mu g/mL). In addition, interferon-gamma treatment resulted in a 32% reduction in expression of transforming growth factor beta in LTS-derived fibroblasts. CONCLUSIONS AND RELEVANCE Interferon-gamma. reduced proliferation, soluble collagen production, and collagen expression in LTS-derived fibroblasts while also reducing the expression of the profibrotic cytokine transforming growth factor beta. These findings suggest that therapeutics aimed at increasing interferon-gamma and the T(H)1 response could attenuate LTS.