Expression of soluble triggering receptor expressed on myeloid cells-1 in childhood CF and non-CF bronchiectasis.

BACKGROUND

Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is demonstrating promise as an inflammatory biomarker of acute infection in various pulmonary conditions; including community acquired pneumonia, ventilator associated pneumonia and non-tuberculous mycobacterial infection.

INTRODUCTION

The expression of sTREM-1 has been poorly studied in all forms of bronchiectasis, both in the context of cystic fibrosis (CF) and non-cystic fibrosis bronchiectasis.

METHOD: Induced sputum samples were collected for sTREM-1 determination in children with HIV-associated bronchiectasis and CF-bronchiectasis. The presence or absence of an exacerbation was noted at study entry. Lung function parameters (FEV1, FVC, FEV1 /FVC, FEF(25-75)) were measured using the Viasys SpiroPro Jaeger Spirometer (Hoechberg, Germany).

RESULT: A total of twenty-six children with HIV-associated bronchiectasis and seventeen with CF were included. With respect to sTREM-1, the levels were readily detected in both groups, but were significantly higher in children with HIV-associated bronchiectasis (1244.0 pg/ml (iqr 194.5; 3755.3 pg/ml) and 204.9  pg/ml (iqr 66.9; 653.6 pg/ml) P = 0.003. There was a positive correlation between sTREM-1 and IL-8 as well as sputum neutrophil elastase in the HIV-bronchiectasis group (r = 0.715 and r = 0.630), respectively both P < 0.005. sTREM-1 was not further increased in subjects presenting with an acute pulmonary exacerbation in the HIV-associated bronchiectasis and in CF participants (P = 0.971 and P = 0.481), respectively. In the CF group sTREM-1 strongly correlated with FVC% predicted and FEV1 % predicted (r = 0.950 and r = 0.954), both P < 0.005.

CONCLUSION

The pulmonary innate immune functions are over-active in HIV-associated bronchiectasis, with readily detected sTREM-1 values, which were higher than those in CF. sTREM-1 does not correlate with markers of HIV-disease activity but does correlate with markers of neutrophilic inflammation. In CF sTREM-1 has a negative correlation with pulmonary function parameters.