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. 2021 Apr 30;6(1):e000733.
doi: 10.1136/bmjophth-2021-000733. eCollection 2021.

SARS-CoV-2 RNA and antibodies in tear fluid

Astrid Muyldermans  1 , Maria Bjerke  2 , Thomas Demuyser  1 , Deborah De Geyter  1 , Ingrid Wybo  1 , Oriane Soetens  1 , Ilse Weets  2 , Robert Kuijpers  3 , Sabine D Allard  4 , Denis Piérard  1 , Peter P M Raus  3
Affiliations

SARS-CoV-2 RNA and antibodies in tear fluid

Astrid Muyldermans et al. BMJ Open Ophthalmol. .

Abstract

Background/aims: SARS-CoV-2 is highly contagious. More evidence concerning extrapulmonary transmission routes such as the eyes is urgently needed. Although the humoral immune response is important in the viral containment, the local response in tears has not yet been studied. The aim of our study was twofold: to assess the prevalence of both SARS-CoV-2 RNA and antibodies in tear fluid.

Methods: In a first series, nasopharyngeal sampling and tear sampling by Schirmer test strips were performed in 26 acutely ill patients with COVID-19 to assess the presence of SARS-CoV-2 RNA by reverse transcription PCR. In a second series, IgG and IgA responses to SARS-CoV-2 spike protein in serum and tear fluid of convalescent individuals (n=22) were compared with control individuals (n=15) by ELISA.

Results: SARS-CoV-2 RNA was detected in tears of 7/26 (26.9%) patients with COVID-19. None of them had ocular symptoms. Convalescent individuals displayed a significant higher ratio of IgG (p<0.0001) and IgA (p=0.0068) in tears compared with control individuals. A sensitivity of 77.3% and specificity of 93.3% was observed for IgG, and 59.1% and 100% for IgA.

Conclusions: Our results demonstrate the presence of SARS-CoV-2 RNA and a local IgG and IgA immune response in tear fluid. These data confirm the possibility of SARS-CoV-2 transmission through tear fluid and the importance of the eye as a first defence against SARS-CoV-2, indicating the potential of tears as a non-invasive surrogate for serum in monitoring the host immune response.

Keywords: COVID-19; diagnostic tests/investigation; immunology; microbiology; tears.

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Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1
Figure 1
Left: scatter plots of anti-SARS-CoV-2 IgG and IgA ratios in tear fluid, indicating the median by a horizontal line and p value between convalescent (n=22) and control employees (n=15). Right: ROC curves of anti-SARS-CoV-2 IgG and IgA ratios in tear fluid of convalescent and control employees. ROC, receiver operating characteristic.
See this image and copyright information in PMC

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