They have the Covid test which has been negative for a number of days that can be close to a year, but nevertheless they suffer from potentially lethal pneumonia, very similar to that associated with an acute Sars-CoV-2 infection. A ‘mystery’ investigated by a study of the University of Trieste, of King’s College of London and of the International Center for Genetic Engineering and Biotechnology (Icgeb) in Trieste, published in the ‘Journal of Pathology’.
The scientists – UniTs reports – analyzed the lung tissue of a particular category of patients, those apparently negative, but whose clinical conditions have progressively worsened up to lead them to death with symptoms completely superimposable to those of an acute Covid infection . The analyzed cohort, despite repeated viral negativity for up to 300 consecutive days, presented evidence of focal or diffuse interstitial pneumonia, accompanied by extensive fibrotic replacement in half of the cases.
“Absolutely unexpected – the experts explain – some significant aspects from a pathological point of view”. The first aspect is that, “despite the apparent virological remission, the pulmonary pathology turned out to be very similar to that observed in acutely infected individuals, with frequent cytological abnormalities, syncytia and the presence of dysmorphic features in the bronchial cartilage”. The second aspect, considered by the authors “perhaps even more disturbing”, is linked to the “absence of viral traces in the respiratory epithelium, consistent with the negativity of the molecular test, while the Spike protein and that of the viral nucleocapsid were identified in the bronchial cartilage and in the parabronchial glandular epitheliumindispensable respectively for the infection and for the replication of the virus”. Therefore “the cartilaginous district appears as a ‘sanctuary’ which makes the virus unidentifiable with any of the methods currently available”. A sort of ‘hideout’ of Sars-CoV-2.
Together, these results indicate that “SARS-CoV-2 infection may persist significantly longer than negative PCR test results suggest – underline the researchers – with clear signs of infection in specific types of cells in the lung. What is the actual role of this latent long-term infection in the clinical picture of the so-called ‘long Covid syndrome'”, Long Covid, however, “still remains to be explored”.
The study, coordinated by Mauro Giacca, professor of Molecular Biology at the University of Trieste, Group Leader of the Laboratory of Molecular Medicine in Icgeb, and in GB director of the School of Cardiovascular Medicine at King’s College London, benefited – reads the a note – from the many years of experience of Rossana Bussani of the Institute of Pathological Anatomy of Asugi (Giuliano Isontina University Health Authority), professor of Pathological Anatomy at the University of Trieste, in the autopsy examination of patients who died at the hospital in the Julian capital. The team of scientists also includes Chiara Collesi, professor of Molecular Biology at the University of Trieste, and Serena Zacchigna, professor of Molecular Biology at the University of Trieste and Group Leader of the Cardiovascular Biology Laboratory in Icgeb.