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. 2021 Jan 1;184(1):186–187. doi: 10.1111/bjd.19595

SARS‐CoV‐2 has not been detected directly by electron microscopy in the endothelium of chilblain lesions: reply from the authors

I Colmenero 1,, C Santonja 2, M Alonso‐Riaño 3, D Andina 4, JL Rodríguez Peralto 5, L Requena 6, A Torrelo 7
PMCID: PMC9214004  PMID: 33325537

Abstract

Linked Articles: Colmenero et al. Br J Dermatol 2021; 183:729–737. Brealey and Miller. Br J Dermatol 2021; 184:186. Colmenero et al. Br J Dermatol 2021; 183:1170–1171.


Dear Editor, We thank Dr Brealey and Dr Miller for their interest in our paper1 and their valuable comments.2

We fully agree that the interpretation of electron microscopy findings can be challenging, even for experts. Differences between viral pathogens and normal subcellular organelles may be subtle, and some cellular components can masquerade as viruses. The size and shape of the particle shown in our paper fit with other descriptions of SARS‐CoV‐2, but there may be a bias in interpretation. As Brealey and Miller state, the location inside the cell is not typical, and the internal pattern of the nucleocapsid is absent, raising reasonable doubts whether this structure represents a clathrin‐coated vesicle. As we already mentioned in our previous letter,3 immune electron microscopy could be the best way to confirm the true nature of this particle, but unfortunately we do not have remaining tissue to perform additional studies.

Since the publication of our series, new evidence has arisen favouring a causal role for SARS‐CoV‐2 in COVID chilblains. Positive immunohistochemistry for SARS‐CoV has been reported by different authors in cutaneous biopsies of COVID chilblains using antibodies directed against different parts of the virus,4, 5 and SARS‐CoV‐2 RNA‐positive cells have been demonstrated by RNAscope.5

We acknowledge that more cases are necessary to demonstrate the presence of coronavirus in skin lesions consistently.

Contributor Information

I. Colmenero, Department of Pathology Hospital Madrid Spain

C. Santonja, Department of Pathology Hospital Madrid Spain

M. Alonso‐Riaño, Department of Pathology Hospital Universitario 12 de Octubre Madrid Spain

D. Andina, Emergency Department Hospital Madrid Spain

J.L. Rodríguez Peralto, Department of Pathology Hospital Universitario 12 de Octubre Madrid Spain

L. Requena, Department of Dermatology Hospital Universitario Fundación Jiménez Díaz Madrid Spain

A. Torrelo, Department of Dermatology Hospital Infantil Universitario Niño Jesús Madrid Spain

References

  1. Colmenero  I, Santonja  C, Alonso‐Riaño  M  et al. SARS‐CoV‐2 endothelial infection causes COVID‐19 chilblains: histopathological, immunohistochemical and ultrastructural study of seven paediatric cases. Br J Dermatol  2020; 183:729‐37. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Brealey  JK, Miller  SE. SARS‐CoV‐2 has not been detected directly by electron microscopy in the endothelium of chilblain lesions. Br J Dermatol  2021;184: 186. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Colmenero  I, Santonja  C, Alonso‐Riaño  M  et al. Chilblains and COVID‐19: why SARS‐CoV‐2 endothelial infection is questioned. Reply from the authors. Br J Dermatol  2021;183: 1170–1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Ko  CJ, Harigopal  M, Gehlhausen  JR  et al. Discordant anti‐SARS‐CoV‐2 spike protein and RNA staining in cutaneous perniotic lesions suggests endothelial deposition of cleaved spike protein. J Cutan Pathol  2020; 10.1111/cup.13866. [DOI] [PubMed] [Google Scholar]
  5. Magro  C, Mulvey  JJ, Laurence  J  et al. The differing pathophysiologies that underlie COVID‐19‐associated perniosis and thrombotic retiform purpura: a case series. Br J Dermatol  2021;184: 141–50. [DOI] [PMC free article] [PubMed] [Google Scholar]

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