BACKGROUND: Respiratory viral infections can increase the risk of chronic lung allograft dysfunction after lung transplantation, but the mechanisms are unknown. In this study, we determined whether symptomatic respiratory viral infections after lung transplantation induce circulating exosomes that contain lung-associated self-antigens and assessed whether these exosomes activate immune responses to self-antigens. METHODS: Serum samples were collected from lung transplant recipients with symptomatic lower-and upper-tract respiratory viral infections and from non-symptomatic stable recipients. Exosomes were isolated via ultracentrifugation; purity was determined using sucrose cushion; and presence of lung self-antigens, 20S proteasome, and viral antigens for rhinovirus, coronavirus, and respiratory syncytial virus were determined using immunoblot. Mice were immunized with circulating exosomes from each group and resulting differential immune responses and lung histology were analyzed. RESULTS: Exosomes containing self-antigens, 20S proteasome, and viral antigens were detected at significantly higher levels (p < 0.05) in serum of recipients with symptomatic respiratory viral infections (n = 35) as compared with stable controls (n = 32). Mice immunized with exosomes from recipients with respiratory viral infections developed immune responses to self-antigens, fibrosis, small airway occlusion, and significant cellular infiltration; mice immunized with exosomes from controls did not (p < 0.05). CONCLUSIONS: Circulating exosomes isolated from lung transplant recipients diagnosed with respiratory viral infections contained lung self-antigens, viral antigens, and 20S proteasome and elicited immune responses to lung self-antigens that resulted in development of chronic lung allograft dysfunction in immunized mice.
ObjectiveThe benefit of direct-acting antivirals (DAAs) against HCV following successful treatment of hepatocellular carcinoma (HCC) remains controversial. This meta-analysis of individual patient data assessed HCC recurrence risk following DAA administration.DesignWe pooled the data of 977 consecutive patients from 21 studies of HCV-related cirrhosis and HCC, who achieved complete radiological response after surgical/locoregional treatments and received DAAs (DAA group). Recurrence or death risk was expressed as HCC recurrence or death per 100 person-years (100PY). Propensity score-matched patients from the ITA.LI.CA. cohort (n=328) served as DAA-unexposed controls (no-DAA group). Risk factors for HCC recurrence were identified using random-effects Poisson.ResultsRecurrence rate and death risk per 100PY in DAA-treated patients were 20 (95% CI 13.9 to 29.8, I2=74.6%) and 5.7 (2.5 to 15.3, I2=54.3), respectively. Predictive factors for recurrence were alpha-fetoprotein logarithm (relative risk (RR)=1.11, 95% CI 1.03 to 1.19; p=0.01, per 1 log of ng/mL), HCC recurrence history pre-DAA initiation (RR=1.11, 95% CI 1.07 to 1.16; p<0.001), performance status (2 vs 0, RR=4.35, 95% CI 1.54 to 11.11; 2 vs 1, RR=3.7, 95% CI 1.3 to 11.11; p=0.01) and tumour burden pre-HCC treatment (multifocal vs solitary nodule, RR=1.75, 95% CI 1.25 to 2.43; p<0.001). No significant difference was observed in RR between the DAA-exposed and DAA-unexposed groups in propensity score-matched patients (RR=0.64, 95% CI 0.37 to 1.1; p=0.1).ConclusionEffects of DAA exposure on HCC recurrence risk remain inconclusive. Active clinical and radiological follow-up of patients with HCC after HCV eradication with DAA is justified.
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