RATIONAL BASADO EN LA PERSISTENCIA DEL VIRUS SARS-COV-2 (COLECTIVO LONGCOVIDACTS)

assays were negative in all 14 individuals at the time of biopsy. However, biopsy samples from
3 of the 14 participants produced PCR amplicons that were sequence verified as SARS-CoV-2.
Immunostaining was performed to determine whether viral protein was also detectable in upper
and lower GI tract, with de-identified biopsies from individuals pre-dating the pandemic (n=10)
serving as controls. ACE2 and SARS-CoV-2 N protein was detected in intestinal enterocytes in 5
of 14 individuals but not in historic control samples. To determine whether viral particles were
present we used electron tomography to examine a tissue sample from one of the individuals
who was positive by immunofluorescence. Particles with typical SARS-CoV-2 morphologies were
found within intracellular membrane-enclosed vesicles consistent with coronavirus exit
compartments in terminal ileum apical epithelial cells, suggesting the presence of intact virions,
3 months after the infection. Particles were also found in vesicles in apical epithelial cells of the
duodenum, although there were fewer and less densely-populated vesicles observed. Our data
indicate that the anti-SARS-CoV-2 memory B cell response evolves during the first 6 months after
infection, with accumulation of Ig somatic mutations, and production of antibodies with
increased neutralizing breadth and potency. Persistent antibody evolution occurs in germinal
centers and requires that B cells are exposed to antigen trapped in the form of immune
complexes on follicular dendritic cells
Persistence and Evolution of SARS-CoV-2 in an Immunocompromised Host (lung, spleen,
plasma) Correspondence NEJM
A 45-year-old man with severe antiphospholipid syndrome. Onday 0, Covid-19 was diagnosed
by SARS-CoV-2 RT-PCR assay of a nasopharyngeal swab specimen. From day 6 through day 68,
the patient quarantined alone at home, but during the quarantine period, he was hospitalized
three times for abdominal pain and once for fatigue and dyspnea. SARS-CoV-2 RT-PCR cycle
threshold (Ct) values increased to 37.8 on day 39 which suggested resolving infection. On day
72, RT-PCR assay of a naso-pharyngeal swab was positive, with a Ct value of 27.6, causing
concern for a recurrence of Covid-19. On day 72 (4 days into another hospital admission for
hypoxemia), RT-PCR assay of a naso-pharyngeal swab was positive, with a Ct value of 27.6,
causing concern for a recurrence of Covid-19. A subsequent RT-PCR assay was negative. On day
143, the RT-PCR Ct value was 15.6,which caused concern for a third recurrence. On day 150, he
underwent endotracheal intubation because of hypoxemia. A bronchoalveolar-lavage specimen
on day 151 revealed an RT-PCR Ct value of 15.8 and grew Aspergillus fumigatus. On day 154, he
died from shock and respiratory failure. We performed quantitative SARS-CoV-2 viral load assays
in respiratory samples (nasopharyngeal and sputum) and in plasma, and the results were
concordant with RT-PCR Ct values, peakingat 8.9 log10 copies per milliliter. Tissue studies
showed the highest SARS-CoV-2 RNA levels in the lungs and spleen. Phylogenetic analysis was
consistent with persistent infection and accelerated viral evolution. Although most
immunocompromised persons effectively clear SARS-CoV-2 infection, this case highlights the
potential for persistent infection and accelerated viral evolution associated with an
immunocompromised state.
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