Evaluation of Anti-SARS-CoV-2 IgA Response in Tears of Vaccinated COVID-19 Subjects

Abstract

Secretory IgA (sIgA), which may play an important role in the early defense against SARS-CoV-2 infection, were detected in the eye of COVID-19 patients. However, an evaluation of the sIgA response in the tears of vaccinated or non-vaccinated COVID-19 subjects is still lacking. Aimed at characterizing sIgA mucosal immunity in the eye, this study analyzed tear samples from 77 COVID-19 patients, including 63 vaccinated and 14 non-vaccinated subjects. The groups showed similar epidemiological features, but as expected, differences were observed in the percentage of asymptomatic/pauci-symptomatic subjects in the vaccinated vs. non-vaccinated cohort (46% and 29% of the total, respectively). Consistent with this, ocular sIgA values, evaluated by a specific quantitative ELISA assay, were remarkably different in vaccinated vs. non-vaccinated group for both frequency (69.8% vs. 57.1%, respectively) and titer (1372.3 U/ml vs. 143.7 U/ml, respectively; p = 0.01), which was significantly differently elevated depending on the type of administered vaccine. The data show for the first time significant differences of available vaccines to elicit sIgA response in the eye and suggest that quantitative tear-based sIgA tests may potentially serve as a rapid and easily accessible biomarker for the assessment of the development of a protective mucosal immunity toward SARS-CoV-2.

Development of an Oral IgA Response against SARS-CoV-2 Following Immunization with Different COVID-19 Vaccines

“…In addition to the oral site, we previously detected sIgAs at the eye level in the conjunctival fluid of about 40% of COVID-19 patients where they were maintained for up to 48 days post COVID-19 onset and whose titer was similarly associated with a mild course of the disease compared to patients with low or no detectable sIgA response in their conjunctival fluid [16]. More recently, we and others also reported the detection of a specific sIgA response at the ocular level following intramuscular SARS-CoV-2 vaccination [20,21].…”

“…The presence and amount of salivary anti-SARS-CoV-2 IgAs were evaluated using the commercial quantitative ELISA assay "RayBio COVID-19 S1RBD", targeting human IgA directed against the receptor-binding domain of the viral spike protein S1-RBD (Ray-Biotech Life, Peachtree Corners, GA, USA), as previously reported [20]. The assay protocol, originally intended for analysis of serum samples, was first optimized for saliva analysis by testing serial salivary dilutions.…”

Serum and Salivary IgG and IgA Response After COVID-19 Messenger RNA Vaccination

“…Importantly, we limited the study to individuals vaccinated at the beginning of the pandemic to select a substantial number of confirmed SARS-CoV-2-naive participants to be included in the study. Since SARS-CoV-2 infection became extremely prevalent in Europe and in the US, we speculate that some of the previous inconsistencies reported in the literature [3][4][5][6][7][8][9][10][11] on saliva IgA responses might relate to difficulties recruiting participants who were truly SARS-CoV-2 naive. Many SARS-CoV-2 infections are indeed asymptomatic and even more so in the recent phases of virus circulation.…”

“…Several studies conclude that humoral mucosal immunity is largely driven by previous infection, with little impact of vaccination, 4 , 5 , 6 while others suggest that mRNA vaccination can by itself elicit long-lasting anti–SARS-CoV-2 mucosal IgA responses. 7 , 8 , 9 , 10 , 11 Herein, we compared individuals with previous SARS-CoV-2 infection and SARS-CoV-2–naive individuals included in the CoviCompare P and CoviCompare M vaccination trials 12 for their saliva and serum responses after 2 different modes of antigenic challenge: infection and vaccination or vaccination alone.…”

Macrophage Activation in Follicular Conjunctivitis during the COVID-19 Pandemic

“…There, electron microscopy (EM) and immunoelectron microscopy (IEM) allow the identification and characterization of viral particles [ 17 ], while PCR is superior to ELISA for sensitivity and accuracy in detecting infections [ 18 ], where the conjunctiva and cornea seem to be the ophthalmic structures most affected by viral infections, as previously summarized by Frezzotti and Guerra [ 19 ], Sen et al [ 20 ], and McHang et al [ 21 ]. A new discovery showed for the first time that in the tears of vaccinated COVID-19 patients, ocular secretory IgA (sIgA) values are remarkably different vs. those of non-vaccinated patients [ 22 ], with significant differences in available vaccines. The IgA receptor (FcαR or CD89) can be found on the surface of neutrophils, eosinophils, monocytes, some macrophages, and dendritic cells [ 23 ].…”