Clinical validation of an immunochromatographic SARS-Cov-2 IgM/IgG antibody assay with Japanese cohort.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has become a major health threat. To overcome COVID-19, appropriate diagnosis methods are urgently needed. The aim of this study was to clinically evaluate the colloidal gold immunochromatography assay for SARS-Cov-2 IgM/IgG antibody (Ab). METHODS: Patients confirmed COVID-19 (n = 51) were recruited prospectively from the Musashino Red Cross hospital and Tokyo Medical and Dental University Medical Hospital, between March and May 2020. And the analytical specificity was assessed with serum samples of patients without COVID-19 (n = 100) collected between August to September 2019 before SARS-CoV-2 was first reported in China. RESULTS: Among COVID-19 patients, a total of 87 serum samples were tested for SARS-Cov-2 IgM/IgG Ab assay. IgM was detected 71.0 %, 86.9 %, and 83.3 % at day8-14, 15-28, >29 after symptom onset and IgG was detected in 81.6 %, 87.0 %, and 94.4 %, respectively. The sensitivity of IgM and IgG Ab after day8 assay was significantly higher than before day7, respectively (p=0.0016, 0.0003). There were no positive results in 100 serum samples from patients without COVID-19. CONCLUSION: The SARS-Cov-2 IgM/IgG Ab assay had 79.7% / 86.1% sensitivity (the 8 days after from onset) and 100% specificity in this population.

Association of gene expression involving innate immunity and genetic variation in interleukin 28B with antiviral response.

UNLABELLED: Innate immunity plays an important role in host antiviral response to hepatitis C viral (HCV) infection. Recently, single nucleotide polymorphisms (SNPs) of IL28B and host response to peginterferon α (PEG-IFNα) and ribavirin (RBV) were shown to be strongly associated. We aimed to determine the gene expression involving innate immunity in IL28B genotypes and elucidate its relation to response to antiviral treatment. We genotyped IL28B SNPs (rs8099917 and rs12979860) in 88 chronic hepatitis C patients treated with PEG-IFNα-2b/RBV and quantified expressions of viral sensors (RIG-I, MDA5, and LGP2), adaptor molecule (IPS-1), related ubiquitin E3-ligase (RNF125), modulators (ISG15 and USP18), and IL28 (IFNλ). Both IL28B SNPs were 100% identical; 54 patients possessed rs8099917 TT/rs12979860 CC (IL28B major patients) and 34 possessed rs8099917 TG/rs12979860 CT (IL28B minor patients). Hepatic expressions of viral sensors and modulators in IL28B minor patients were significantly up-regulated compared with that in IL28B major patients (≈ 3.3-fold, P < 0.001). However, expression of IPS-1 was significantly lower in IL28B minor patients (1.2-fold, P = 0.028). Expressions of viral sensors and modulators were significantly higher in nonvirological responders (NVR) than that in others despite stratification by IL28B genotype (≈ 2.6-fold, P < 0.001). Multivariate and ROC analyses indicated that higher RIG-I and ISG15 expressions and RIG-I/IPS-1 expression ratio were independent factors for NVR. IPS-1 down-regulation in IL28B minor patients was confirmed by western blotting, and the extent of IPS-1 protein cleavage was associated with the variable treatment response. CONCLUSION: Gene expression involving innate immunity is strongly associated with IL28B genotype and response to PEG-IFNα/RBV. Both IL28B minor allele and higher RIG-I and ISG15 expressions and RIG-I/IPS-1 ratio are independent factors for NVR.

Potential relevance of cytoplasmic viral sensors and related regulators involving innate immunity in antiviral response.

BACKGROUND & AIMS: Clinical significance of molecules involving innate immunity in treatment response remains unclear. The aim is to elucidate the mechanisms underlying resistance to antiviral therapy and predictive usefulness of gene quantification in chronic hepatitis C (CH-C). METHODS: We conducted a human study in 74 CH-C patients treated with pegylated interferon alpha-2b and ribavirin and 5 nonviral control patients. Expression of viral sensors, adaptor molecule, related ubiquitin E3-ligase, and modulators were quantified. RESULTS: Hepatic RIG-I, MDA5, LGP2, ISG15, and USP18 in CH-C patients were up-regulated at 2- to 8-fold compared with nonhepatitis C virus patients with a relatively constitutive Cardif. Hepatic RIG-I, MDA5, and LGP2 were significantly up-regulated in nonvirologic responders (NVR) compared with transient (TR) or sustained virologic responders (SVR). Cardif and RNF125 were negatively correlated with RIG-I and significantly suppressed in NVR. Differences among clinical responses in RIG-I/Cardif and RIG-I/RNF125 ratios were conspicuous (NVR/TR/SVR = 1.3:0.6:0.4 and 2.3:1.3:0.8, respectively). Like viral sensors, ISG15 and USP18 were significantly up-regulated in NVR (4-fold and 2.3-fold, respectively). Multivariate and receiver operator characteristic analyses revealed higher RIG-I/Cardif ratio, ISG15, and USP18 predicted NVR. Lower Cardif in NVR was confirmed by its protein level in Western blot. Also, transcriptional responses in peripheral blood mononuclear cells to the therapy were rapid and strong except for Cardif in not only a positive (RIG-I, ISG15, and USP18) but also in a negative regulatory manner (RNF125). CONCLUSIONS: NVR may have adopted a different equilibrium in their innate immune response. High RIG-I/Cardif and RIG-I/RNF125 ratios and ISG15 and USP18 are useful in identifying NVR.

Relationship between polymorphisms of the inosine triphosphatase gene and anaemia or outcome after treatment with pegylated interferon and ribavirin.

BACKGROUND: A genome-wide association study revealed an association between variants of the inosine triphosphatase (ITPA) gene and ribavirin (RBV)-induced anaemia. The aim of this study was to replicate this finding in an independent Japanese cohort and to define a method to allow pretreatment prediction of anaemia in combination with other factors. METHODS: Genotype 1b chronic hepatitis C patients (n=132) treated with pegylated interferon (PEG-IFN)-α and RBV for 48 weeks were genotyped for ITPA rs1127354 and examined for anaemia and treatment outcome. RESULTS: Variants of the ITPA gene protected against severe anaemia throughout the 48-week treatment period and were associated with lower incidence of anaemia-related RBV dose reduction. A combination of the ITPA genotype with baseline haemoglobin (Hb) and creatinine clearance (CLcr) levels predicted severe anaemia with high accuracy (90% sensitivity and 62% specificity). Among a subset of patients with the IL28B genotype of TT at rs8099917, patients with variants of the ITPA gene were associated with a higher rate of receiving >80% of the expected RBV dose, a higher rate of sustained virological response (SVR), and a lower rate of relapse. CONCLUSIONS: The variants of the ITPA gene, which could protect against haemolytic anaemia and RBV dose reduction, were associated with a high rate of SVR by standard PEG-IFN and RBV therapy in a subset of Japanese patients with the favourable TT genotype at rs8099917 of IL28B. A combination of ITPA genetic polymorphisms with baseline Hb and CLcr levels further improves the predictive accuracy of severe anaemia.

A comparison of the exponential decay slope between PEG-IFN alfa-2b/ribavirin and IFN alfa-2b/ribavirin combination therapy in patients with chronic hepatitis C genotype 1b infection and a high viral load.

OBJECTIVES: A high virological response rate can often be shown to be obtained with PEG-IFN alpha-2b and ribavirin combination therapy in chronic hepatitis C patients. Viral dynamics have been utilized for the evaluation of antiviral effects, especially the exponential second decay slope, which represents the elimination of infected cells. METHODS: Forty-nine patients were randomly assigned to the IFN alpha-2b group (n = 26) or the PEG-IFN alpha-2b group (n = 23). Ribavirin was administered equally to both groups. Measuring the serum concentration of HCVRNA, the exponential viral decay during phase 1 and 2 was calculated. RESULTS: The exponential decay slope in phase 2 during the first 2 weeks was greater in the IFN alpha-2b group than in the PEG-IFN alpha-2b group; however, from weeks 3 to 4, it was greater in the PEG-IFN alpha-2b group than in the IFN alpha-2b group. Interestingly, in the PEG-IFN alpha-2b group, the exponential decay slope was greater from weeks 3 to 4 after initiating combination therapy than during the weeks 1-2 (p < 0.01), despite administration of the same PEG-IFN alpha-2b dose (1.5 microg/kg once weekly). CONCLUSIONS: In PEG-IFN alpha-2b and ribavirin combination therapy, elimination of infected cells may be pronounced following an increase in serum ribavirin concentration in chronic hepatitis C patients with genotype 1b infection and a high viral load.