‘Fingerprints’ described for the first time in skin tissue; the matterof “Patient 1” arises again   

Covid ‘fingerprints’ were described for the first time in skin tissue, starting with a biopsy performed on a young woman in Milan in November 2019, further confirming how the virus Sars-CoV-2 was circulating in Italy several months before the explosive outbreak of the epidemic in northern Italy.

The new scientific result comes from a study coordinated by Raffaele Gianotti, researcher from the University of Milan, with support of the laboratories of the European Institute of Oncology and Centro Diagnostico Italiano, and published in the British Journal of Dermatology.

The university points out that the study, based on data present in the global literature, identified “the oldest validation of the presence of the virus SARS-CoV-2 in a human being”. 

The premise

Skin disorders, indicates the university, are present in 5-10% of patients with Covid-19 infection. Raffaele Gianotti, dermatopathologist at the University of Milan and the Fondazione Cà Granda Ospedale Maggiore Policlinico, explains how the study came about: “After studying the skin manifestations in patients with COVID-19 in the Milan area I re-examined under the microscope the biopsies of atypical skin disorders performed in late 2019, where it was not possible to make a precise diagnosis.We searched in the past because our work published in international magazines already showed that in this pandemic cases exist in which the only sign of infection from COVID-19 is a skin disorder. I asked myself if we could find clues to the presence of SARS-CoV-2 in patients with only skin disorders before the epidemic was officially recognised.” 

Results and techniques

The biopsy of a young women dating to November 2019, performed due to an atypical dermatitis, showed the presence of gene sequences of the RNA of SARS-CoV-2 identified by means of two different techniques on the skin tissue: immunohistochemical and RNA-FISH. “Metaphorically speaking,” notes Gianotti, “we found the ‘fingerprints’ of COVID-19 in the skin tissue.”   

Giovanni Fellegara, head of the Laboratory of Pathological Anatomy at the Centro Diagnostico Italiano adds that “in the case of the young woman we were able to demonstrate through immunohistochemical investigations performed at our laboratory the presence of viral antigens in the sweat glands.” The data was later confirmed by evidence in the same structures of gene sequences of viral RNA identified using the technique RNA-FISH carried out at the EIO.

"We demonstrated the presence of SARS-CoV-2 viral sequences, although scant, on the histological preparation of 2019 and also in six patients in 2020 affected only by dermatitis, but without systemic symptoms from COVID-19 infection," explains Massimo Barberis, Director of the Clinical Unit of Histopathological and Molecular Diagnostics at the European Institute of Oncology (EIO).

The patient, who was contacted afterwards, reported no systemic symptoms of COVID-19, the disappearance of skin lesions after five months and the positivity of anti-bodies anti SARS-CoV-2 in the peripheral blood to June 2020.

The precedents

The new study arrives following others, which had increasingly pre-dated the so-called Italian Patient 1, i.e., the first certified case. A study had detected the presence of Sars-CoV-2 in wastewater in northern Italy in December 2019; in another case the Istituto Nazionale dei Tumori of Milan had found antibodies to the virus in patients who had undergone a screening for lung cancer between September 2019 and March 2020; and there was also the case that had dated the first ascertained appearance of Covid-19 in November 2019, by later reviewing a test performed in early December 2019 for a suspected case of measles.