Observation of Collider Muon Neutrinos with the SND@LHC Experiment

We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A dataset of proton-proton collisions at sqrt[s]=13.6  TeV collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of 36.8  fb^{-1}. The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudorapidity region of 7.2<η<8.4, inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ν_{μ} interaction candidate events remain with an estimated background of 0.086 events, yielding a significance of about 7 standard deviations for the observed ν_{μ} signal.

Evaluation of the new automated enzymun-test anti-HBc plus for the detection of hepatitis B virus core antibody

The new automated Enzymun-Test anti-HBc Plus for the detection of antibodies to hepatitis B virus (HBV) core antigen (anti-HBc) after pretreatment with reducing agents dithiothreitol (25 degrees C; + DTT) or potassium bisulfite (37 degrees C; + MBS) was evaluated by testing 571 serum and plasma samples. The panel included dilution series of reference standards and samples from chronic carriers, one seroconversion panel, samples from patients in acute or chronic stage of the disease or resolved hepatitis B, preselected sera from blood donors that were initially reactive in an anti-HBc assay without pretreatment, potentially cross-reactive serum samples obtained from patients suffering from other diseases or with passed infections other than HBV, pregnant women and individuals with HBV vaccination. The IMx CORE(TM) (Abbott Diagnostics) served as reference assay. Discrepant samples were further investigated with two different commercial anti-HBc enzyme immunoassays, other HBV-specific serological markers and HBV DNA hybridization. The sensitivity of the Enzymun-Test Anti-HBc Plus (25 degrees + DTT, and 37 degrees C; + MBS) in comparison to the reference assay was 100%. The IMx CORE showed a twofold higher sensitivity than Enzymun-Test Anti-HBc Plus for anti-HBc detection in dilution series of serum samples from HBV carriers. The agreement in terms of specificity of the Enzymun-Test Anti-HBc Plus (25 degrees C; + DTT, and 37 degrees C; + MBS) and in comparison to IMx CORE was 97.4 and 96.4%, respectively. After resolution of discrepant results (3 samples were tested false negative with IMx CORE), the agreement in terms of specificity of the Enzymun-Test Anti-HBc Plus (25 degrees C; + DTT, and 37 degrees C; + MBS) in comparison to the combination of the comparative assays was 98.3 and 97.4%, respectively. In conclusion, the new automated Enzymun-Test Anti-HBc Plus with sample pretreatment with DTT (25 degrees C; + DTT) or MBS (37 degrees C; + MBS) permits a highly sensitive and specific detection of anti-HBc in diagnostic virology and blood donation testing.

Multicenter evaluation of a new rapid automated human immunodeficiency virus antigen detection assay

Although human immunodeficiency virus (HIV) antigen assays are of limited value for monitoring antiretroviral therapy, they play an important role for confirmatory testing of fourth generation HIV screening enzyme immunoassay (EIA) reactive samples. In a multicenter study, a new automated rapid p24 antigen assay, Elecsys HIV Ag (Roche Diagnostics Boehringer Mannheim GmbH, Penzberg, Germany), was compared to FDA licensed tests (Abbott HIV-1 Ag monoclonal and Coulter HIV-1 p24 antigen assay). In the evaluation 27 seroconversion panels were included, sera from the acute phase of infection, single and follow-up samples from HIV antibody positive patients, dilution series of HIV antigen positive standards, sera and cell culture supernatants infected with different HIV-1 subtypes (A-H, and O) HIV-2 and recombinant HIV-1 (gag/env) isolates. To challenge the specificity of the new assay, 2565 unselected blood donors, sera from pregnant women, dialysis and hospitalized patients and 407 potentially cross-reactive samples were investigated. Acute HIV infection was detected in three to eight seroconversion panels earlier with Elecsys HIV Ag than with the alternative assays. Higher numbers of serum samples from HIV infected patients tested positive by Elecsys HIV Ag than with the comparative assays. All HIV-1 subtypes and HIV-2 isolates were recognized with Elecsys HIV Ag. Abbott HIV-1 Ag monoclonal and Coulter HIV-1 p24 antigen assay showed a variable sensitivity for the different HIV-1 subtypes. The specificity of Elecsys HIV Ag and Coulter HIV-1 p24 antigen assay were 99.8 and 99.93%, respectively. All the eight sera that were false reactive by Elecsys HIV Ag were tested negative with the Elecsys HIV Ag Neutralization Test. In conclusion, Elecsys HIV Ag was more sensitive than the alternative assays and showed a high specificity in combination with the neutralization assay. The very short incubation time of 18 min and the fully automated procedure of Elecsys HIV Ag which permits direct testing from the primary patient blood collection tube, represent a major improvement for routine laboratory diagnosis in comparison to the alternative assays.

HIV infection acquired by a nurse

We report here the history of the first case of occupationally acquired HIV infection in Italy. Results of serological investigations sequentially performed allow the investigators to outline the natural history of the infection in this case.