The expression of triggering receptor expressed on myeloid cells receptor-1 in Aspergillus infected mice

Abstract

Objective: To investigate the expression of triggering receptor expressed on myeloid cells receptor-1 (TREM-1) in plasma and bronchoalveolar lavage fluid (BALF) and its correlation with Galactomannan, IFNγ, IL-6 and IL-10 in Aspergillus infected mice. Methods: Cyclophosphamide(CTX) was intraperitoneally injected and fumigatus spore suspension was inhaled by nose to establish the immunocompromised invasive pulmonary aspergillosis(IPA) mouse model.Healthy controls, immunocompromised only and IPA only groups were also established. Each group had 6 mice. After inoculation, mice were sacrificed. Lung tissue specimens, BALF, and plasma samples were collected. Plasma and BALF soluble TREM-1 (sTREM-1), Galactomannan, IFNγ, IL-6, and IL-10 were detected by ELISA. Results: Positive Aspergillus fumigatus was found by tissue culture in the lung. Infiltration of inflammatory cells, blood congestion and interstitial lung tissue injury were observed in histological sections of both IPA and immunocompromised IPA mice. Compared to IPA group [(453.78±74.18) ng/L, P<0.001; (10.21±1.46) ng/L, P<0.001] and control group [(245.16±65.85) ng/L, P<0.001; (6.60±3.74) ng/L, P<0.001], the plasma and BALF sTREM-1 significantly increased in immunocompromised IPA group [(1 537.64±359.52) ng/L; (20.12±2.72) ng/L]. Compared to control group, both the BALF sTREM-1 in IPA group (P=0.041) and the plasma and BALF Galactomannan, IFNγ, IL-6, and IL-10 levels in IPA and immunocompromised IPA groups were significantly higher (P<0.01). Pearson correlation analysis showed that plasma and BALF sTREM-1 were significantly correlated with Galactomannan (r=0.83, P<0.001; r=0.82, P<0.001), IFNγ (r=0.79, P<0.001; r=0.61, P<0.01), IL-6 (r=0.81, P<0.001; r=0.66, P<0.01), and IL-10 (r=0.70, P=0.001; r=0.54, P=0.02). Conclusions: Plasma and BALF sTREM-1 appears highly expressed in Aspergillus infected mice. sTREM-1 in mice plasma and BALF is closely correlated with Galactomannan, IFNγ, IL-6, and IL-10 levels, which suggests that sTREM-1 has great diagnostic value during invasive fungal infection.