In patients with COVID-19, the anti-SARS-CoV-2 IgA could be found in ocular secretions, according to findings published in Clinical Ophthalmology.
Researchers conducted a study to assess the presence of anti-SARS-CoV-2 IgA, the immunoglobulin produced on mucosal surfaces, in the conjunctival secretions of those with confirmed COVID-19 cases. The study consisted of examining secretions in 44 patients who were confirmed positive for COVID-19 using nasopharyngeal swabs from February 17 to February 28, 2021.
For the collection of tears, one drop of Proparacaine (0.5%) was installed into the eye. While closed for 2 minutes, tears were collected from the lower fornix using a polyester fiber rod. For the detection of SARS-CoV-2 IgA antibody in tear samples, researchers used an iFlash 3000 CLIA analyzer and YHLO-CLIA-2019-nCOV IgA kits.
The study also involved the examination of ocular manifestations including conjunctival, corneal, or retinal issues using a portable slit-lamp and indirect ophthalmoscopy. It found that, while there was no correlation with age, sex of severity of COVID-19, the IgA reactivity and titre were positively associated with ocular symptoms.
However, the researchers note that some ocular medications have an effect on the severity of COVID-19, and therefore, they recommend future investigation into each medication and viral activity. Though not statistically significant, the study’s finding of the correlation between severity of COVID-19 symptoms and IgA titre suggests that the virus could be spread by those with mild cases.
The researchers explain that, in addition to these correlations, the present study showed a statistically insignificant correlation between ocular symptoms and severe general symptoms of COVID-19. However, they note that past studies found no correlation at all between the two.
“This can be explained by the idea that ocular symptoms could occur as an immune response and become more evident when there is a greater immune response in the form of virus/IgA interaction,” the researchers say. “Confirmation of this explanation requires further investigation.”
Study limitations include small sample size and a limited body of past research on the presence of IgA in tears.
Mahmoud H, Hamody A, Hefny H, Tohamy D, Awny I. Evaluation of anti-SARS-CoV-2 IgA in the conjunctival secretions of COVID-19 patients. Clin Ophthalmol. 2021;15(4):1933-1937. doi:10.2147/opth.s312942.