Application of a truncated ORF2 protein-based ELISA for diagnosis of hepatitis E in an endemic area.

Enterically transmitted waterborne hepatitis E (HE) caused due to hepatitis E virus (HEV) prevails as a significant public health problem endemic to India. Due to short-term viremia/fecal excretion and poor in vitro transmissibility of HEV, HE diagnosis depends on detection of specific IgM antibodies in serum. Present study evaluated performances of two in-house and six commercial IgM detection enzyme-linked immunosorbent assays (ELISAs) using sera collected from volunteers/acute hepatitis patients (n = 716). The in-house ELISAs were based on complete and truncated open reading frame 2 (ORF2) proteins containing neutralizing epitope/s region of genotype 1 HEV (ORF2p, 1-660 amino acid (a.a.) and T1NEp, 458-607 a.a., respectively). The commercial ELISAs included Wantai (China), MP Diagnostics (MPD) (Singapore), DIA.PRO Diagnostics (Italy), MBS (Italy), abia (Germany), and ImmunoVision (USA). T1NE ELISA showed 97.0% positive percent agreement (PPA), 99.4% negative percent agreement (NPA), and 98.6% concordance (κ = 0.97, P = 0.0000) with ORF2 ELISA. ORF2, T1NE, Wantai, and MPD ELISAs agreed on results for 88% of sera tested. Two percent sera showed reactivity in each combination of three and two of aforementioned four ELISAs. Remaining 8% sera were single ELISA reactive. PPA and NPA value ranges were 76.3-99.0% and 84.8-99.5%, respectively. Pairwise concordances between all the eight ELISAs ranged from 88.0 to 100% (κ: 0.74-1.00). Both the in-house ELISAs agreed better with Wantai over MPD ELISA. In conclusion, both ORF2 and T1NE ELISAs were equally efficient in diagnosing HEV infections. T1NEp proved to be an excellent tool in HE sero-diagnosis and is worth exploring in development of simple rapid tests. KEY POINTS: • In-house ELISA based on bacterially expressed neutralizing epitope/s region protein • In-house ELISA based on complete ORF2 protein expressed in insect cells • Comparison of two in-house and six commercial anti-HEV IgM antibody detection ELISAs.

Pro-inflammatory CXCL-10, TNF-α, IL-1ß, and IL-6: biomarkers of SARS-CoV-2 infection.

Currently, the world is witnessing the pandemic of COVID-19, a disease caused by the novel coronavirus SARS-CoV-2. Reported differences in clinical manifestations and outcomes in SARS-CoV-2 infection could be attributed to factors such as virus replication, infiltration of inflammatory cells, and altered cytokine production. Virus-induced aberrant and excessive cytokine production has been linked to the morbidity and mortality of several viral infections. Using a Luminex platform, we investigated plasma cytokine and chemokine levels of 27 analytes from hospitalized asymptomatic (n = 39) and mildly symptomatic (n = 35) SARS-CoV-2-infected patients (in the early phase of infection), recovered individuals (45-60 days postinfection) (n = 40), and uninfected controls (n = 36) from the city of Pune located in the state of Maharashtra in India. Levels of the pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α and the chemokine CXCL-10 were significantly higher, while those of the antiviral cytokines IFN-γ and IL-12 p70 were significantly lower in both asymptomatic and mildly symptomatic patients than in controls. Comparison among the patient categories revealed no difference in the levels of the cytokines/chemokines except for CXCL-10 being significantly higher and IL-17, IL-4, and VEGF being significantly lower in the mildly symptomatic patients. Interestingly, levels of all key analytes were significantly lower in recovered individuals than in those in both patient categories. Nevertheless, the level of CXCL10 was significantly higher in the recovered patients than in the controls, indicating that the immune system of SARS-CoV-2 patients may take a longer time to normalize. Our data suggest that IL-6, IL-1ß, TNF-α, CXCL-10, and reduced antiviral cytokines could be used as biomarkers of SARS-CoV-2 infection.