To investigate the efficacy of varying doses of methylprednisolone (MP) on mice with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) induced with influenza A virus (IAV).

Mouse model of COPD was established using LPS combined with smoking for 12 weeks, and then these COPD mice were treated with administration of 40 μL IAV via nasal drip to establish a AECOPD model. A total of 15 AECOPD mice were randomly divided into low-, medium- and high-dose MP groups, oseltamivir group and blank group. The body weight and survival time were monitored within 10 d after IAV infection. On days 1, 3, and 5 post-treatment, lung function was assessed using whole-body plethysmography (WBP), inflammatory factors in bronchoalveolar lavage fluid (BALF) were quantified with ELISA, viral titers in BALF were determined using plaque assays, and colony-forming units were evaluated with blood agar plates. Immunofluorescence analysis: ① Pulmonary immunofluorescence assay: Mice were randomly categorized into (n=4): LPS 1-day group, LPS 3-day group, and LPS+MP treatment group. All groups received an initial dose of LPS via atomization; subsequently, the LPS+MP treatment group received a single gavage dose of MP. Lung tissues were harvested from the 1-day LPS group on 1 d post-treatment, and from the 3-day LPS and LPS+MP groups on 3 d for immunofluorescence staining. ② Cellular immunofluorescence assay: Mouse bone marrow neutrophils were classified into blank control (no intervention), LPS stimulation (LPS group), MP intervention with LPS stimulation (LPS+MP group), and MP intervention alone (MP group). The above cells were collected in 4 h after corresponding interventions for subsequent cellular immunofluorescence analysis.

① The medium-dose MP group demonstrated the most significant improvement in survival rate, weight recovery, and lung function when compared to other groups (P< 0.05). ② Treatment of medium-dose MP obviously reduced the levels of IL-6 and neutrophil extracellular traps (NETs) (P< 0.05), while, elevated inflammatory factors and NETs were observed in the high-dose MP group on day 5 post-treatment. ③ Notable decline in the lung injury score was found in the medium-dose MP group than the other groups (P< 0.05). ④ The high-dose MP group exhibited substantial bacterial proliferation and delayed viral clearance since day 5 after treatment.

Medium-dose MP shows best efficacy in treatment of IAV-induced AECOPD, and the dose neither delays viral clearance nor increases the risk of bacterial infection following viral infection.

To explore the clinical significance of serum cytokine expression in the hepatitis B surface antigen (HBsAg) sero-clearance in patients with severe hepatitis B.

A nested case-control trial was conducted on 14 inpatients with severe hepatitis B admitted in our hospital from 2006 to 2020. Of them, 7 patients (aged 36.57±3.15 years) achieved HBsAg sero-clearance within 1 year after the onset of hepatitis B flares (with abrupt rise of ALT level to >5 times the upper limit of normal during HBV infection) and were assigned into HBsAg clearance group, while the other 7 patients (aged 34.14±2.97 years) only obtained HBsAg decreased less than 1 g within 1 year after the onset (HBsAg non-clearance group). Then, multiplex liquid-chip assay based on Luminex xMAP was used to detect the expression levels of 48 cytokines such as IFN-γ and IL-2 in serum samples of these 14 patients.

The serum levels IFN-γ, IL-2Ra and SDF-1α were significantly lower in the HBsAg clearance group than the HBsAg non-clearance group (P<0.05), but no statistical differences were observed in other 39 cytokines between the 2 groups. And there were 5 cytokines having no mutual expression in both groups. The copy number of HBV DNA was positively correlated with serum HGF (r=0.675, P=0.008) and SDF-1α levels (r=0.587, P=0.027), while negatively with IP-10 (r=-0.600, P=0.023) and MIG level (r=-0.640, P=0.014). Meanwhile, a positive correlation was found between HBsAg titer and IL12-p70 level (r=0.593, P=0.025), and a negative correlation between HBsAg titer and TNF-α level (r=-0.609, P=0.021). In addition, the serum total bilirubin level was positively correlated with the expression of SCGF-β (r=0.543, P=0.045).

Three differentially expressed cytokines and some cytokines related to HBV DNA level and HBsAg titer are found, which may provide new insights into the underlying immunological mechanism of HBV virus clearance caused by hepatitis flares. Meanwhile, it also provides potential biomarkers for HBsAg serological clearance in patients with severe hepatitis B.