Th1/Th2 cytokine levels: A potential diagnostic tool for patients with necrotizing fasciitis.

INTRODUCTION: Necrotizing fasciitis (NF) has emerged as rare but rapidly progressive, life-threatening severe skin and soft tissue infection. We conducted a study to investigate whether Th1/Th2 cytokines could serve as biomarkers to distinguish NF from class III skin and soft tissue infections (SSTIs). METHODS: A retrospective review was performed for 155 patients suffering from serious skin and soft tissue infections from October 2020 to February 2022. Th1/Th2 cytokines were obtained from peripheral blood and wound drainage fluid samples. Data on demographic characteristics, causative microbiological organisms, Th1/Th2 cytokines, c-reactive protein, procalcitonin and white blood cell (WBC) were extracted for analysis. Factors with statistical difference(p < 0.1) were included in the multivariate logistic regression model. The clinical differential diagnostic values of interleukin-2(IL-2), IL-6, IL-10, tumor necrosis factor-α (TNF-α) and interferon-r (IFN-r) were analyzed by receiver operating characteristic (ROC) curve. RESULTS: Among the 155 patients, 66(43%) patients were diagnosed as NF. We found no significant difference for sex, age, location of infection, coexisting condition, predisposition, duration of symptoms before admission and micro-organisms, WBC, procalcitonin and c-reactive protein in NF and class III SSTIs group. NF had higher levels of IL-6 in serum (50.46 [24.89, 108.89] vs. 11.87 [5.20, 25.32] pg/ml; p＜0.01), IL-10 in serum (3.45 [2.03, 5.12] vs. 2.51 [1.79, 3.29] pg/ml; p＜0.01), IL-2 in wound drainage fluid (0.89 [0.49, 1.33] vs. 0.63 [0.14, 1.14] pg/ml; p = 0.02), IL-6 in wound drainage fluid (5000.84 [1392.30, 13287.19] vs. 1927.82 (336.65, 6759.27) pg/ml; p＜0.01), TNF-a in wound drainage fluid (5.20 [1.49, 22.97] vs. 0.96 [0.12, 3.21] pg/ml; p＜0.01) and IFN-r in wound drainage fluid (1.32 [0.47, 4.62] vs. 0.68 [0.10, 1.88] pg/ml; p = 0.02) as compared to the class III SSTIs. Multivariate logistic regression analyses showed that IL-6 in serum, IL-10 in serum and TNF-a in wound drainage fluid exhibited independently significant associations with diagnosis of NF(p＜0.05). In ROC curve analysis of IL-2, IL-6, IL-10, TNF-a and IFN-r for diagnosis of NF, the area under the curve (AUC) of IL-6 in serum could reach to 0.80 (p＜0.001). Using 27.62 pg/ml as the cut off value, the sensitivity was 74% and the specificity was 79% in IL-6 in serum. CONCLUSIONS: Th1/Th2 cytokines, IL-6 in serum in particular, are potential biomarkers for the diagnosis of NF in the early stage. However, larger patient populations with multiple centers and prospective studies are necessary to ensure the prognostic role of Th1/Th2 cytokines.

Preparation and evaluation of virus-like particle vaccine against H3N8 subtype equine influenza.

To prevent and control H3N8 subtype equine influenza, we prepared virus-like particles (VLPs) comprising the HA, NA and M1 proteins of H3N8 equine influenza virus (EIV) through the insect cell-baculovirus expression system. The results of Western blot and hemagglutination analyses demonstrated that the constructed VLPs comprising HA, NA and M1 proteins have good hemagglutination activity. Immunoelectron microscope revealed that the VLPs share similar morphology and structure with natural virus particles. The hyperimmune serum from horses immunized with the VLPs were injected into mice by means of artificial passive immunization and then challenge, or challenge following by injecting hyperimmune serum. The results showed that the equine hyperimmune serum has good preventive and therapeutic efficacy against the infection of H3N8 EIV. The study provides a technical foundation for the development of H3N8 EIV VLP vaccine.

Characterization of Newcastle disease virus obtained from toco toucan.

Given that the current Newcastle disease virus (NDV) infection in wild birds poses the threat to poultry, surveillance of Newcastle disease in captive wild birds was carried out in Jilin, China in 2018. Here, an NDV strain obtained from toco toucan was firstly characterized. The results showed that the F gene of the NDV isolate Toucan/China/3/2018 is classified as genotype II in class II. Sequence analysis of the F0 cleavage site was 113RQGR/L117, which supports the result of the intracerebral pathogenicity index assay indicating classification of the isolate as low-pathogenicity. Experimental infection demonstrated that Toucan/China/3/2018 can effectively replicate and transmit among chickens. To our knowledge, this is the first report on genetically and pathogenically characterizing NDV strain isolated from toucan, which enriches the epidemiological information of NDV in wild birds.