Pathogens (Sep 2022)

IgA-Based Secretory Response in Tears of COVID-19 Patients: A Potential Biomarker of Pro-Inflammatory State in Course of SARS-CoV-2 Infection

  • Anna Niedźwiedź,
  • Ewa Pius-Sadowska,
  • Miłosz Kawa,
  • Agnieszka Kuligowska,
  • Miłosz Parczewski,
  • Krzysztof Safranow,
  • Krzysztof Kozłowski,
  • Bogusław Machaliński,
  • Anna Machalińska

DOI
https://doi.org/10.3390/pathogens11101098
Journal volume & issue
Vol. 11, no. 10
p. 1098

Abstract

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Mucosal immunity, including secretory IgA (sIgA), plays an important role in the early defence against SARS-CoV-2 infection. However, a comprehensive evaluation of the local immune response in tears in relation to blood antibody reservoirs has not yet been conducted. A total of 179 symptomatic laboratory-confirmed COVID-19 patients were included in this single-centre study. Conjunctival swabs were analysed by a reverse transcription polymerase chain reaction for the detection of SARS-CoV-2 RNA. In parallel, tear samples collected by Schirmer test strips and plasma samples were analysed by ELISA to detect anti-S1 IgA levels. The concentrations of selected inflammatory cytokines in tears were determined by a magnetic bead assay. Anti-SARS-CoV-2 sIgA was present in the tears of 81 (45.25%) confirmed COVID-19 patients, and the tear IgA levels were correlated with the plasma IgA levels (Rs = +0.29, p = 0.0003). SARS-CoV-2 RNA in the conjunctival sac was identified in 18 COVID-19 patients (10%). Positive correlations between the tear IgA level and the concentrations of several cytokines TNF-α (Rs = +0.23, p = 0.002), IL-1β (Rs = +0.25, p p = 0.007), IL-4 (Rs = +0.16, p = 0.04), IL-5 (Rs = +0.36, p p p p p < 0.001) were also found. Quantitative tear film-based sIgA could potentially serve as a rapid and easily accessible biomarker of external mucosal immunity to SARS-CoV-2. The concentration of sIgA is directly related to individual host immune responses to SARS-CoV-2 infection.

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