The aim of this prospective follow-up study conducted by Italian authors was to determine whether healthcare workers who had received three doses of COVID-19 mRNA vaccine had the production of autoantibodies, focusing on detection of antibodies to nuclear antigens (antinuclear antibodies, ANA). The results showed that a significant proportion (29%) of healthcare workers developed de novo autoantibody production after mRNA-based anti-SARSCoV-2 vaccination.
The vaccines BNT162b2 (Pfizer- BioNTech) and mRNA 1273 (Moderna) were the first mRNA-based vaccines ever approved. Currently, their effects and possible ability to stimulate an autoimmune reaction are still unclear. New-onset autoimmune phenomena have been reported after COVID-19 vaccination, including immune thrombotic thrombocytopenia, autoimmune liver diseases, IgA nephropathy, rheumatoid arthritis, and systemic lupus erythematosus. Antiphospholipid antibodies are among the most commonly inducible antibodies after infection or vaccination. Researchers hypothesized that the development of autoantibodies after vaccination is related to cross-reactivity between antigens or to the effect of the adjuvant.
About the study
The study included a total of 77 healthcare workers (60 women and 17 men, ages 26–67 years, with a median age of 48) who received COVID-19 mRNA BNT162b2 or mRNA 1273 vaccines. They did not have previous COVID-19 infection or previous autoimmune disease. All subjects were vaccinated with three doses of the COVID-19 mRNA vaccines. All received two doses of the BioNtech/Pfizer BNT162b2 mRNA, half received a third dose of the same vaccine, and the other half received Moderna (Spikevax) as a third dose.
The blood samples were taken before vaccination, after receiving the second dose of vaccine (three months after the first dose), and after receiving the third dose of vaccine (12 months after the first dose). All participants experienced mild or no symptoms after vaccinations.
All samples were analyzed for the presence of antinuclear antibodies by indirect immunofluorescence. Other autoantibodies such as anti-smooth muscle antibodies, anti-myeloperoxidase, anti-proteinase 3, anti-citrullinated peptide antibodies, and anti-phospholipid antibodies (anticardiolipin and anti-beta-2- glycoprotein) were also evaluated.
Prior to vaccination, 25 out of 77 (35%) participants were already positive for ANA, and 23 of them maintained this positivity after receiving the second or third doses of vaccine. 52 out of 77 participants were found to be negative for ANA.
Six out of 52 participants who were negative for ANA before vaccination became positive for ANA after the second vaccination, while 46 out of 52 participants remained negative for ANA.
16 out of 46 participants who were negative for ANA after the second vaccination became positive for ANA after the third vaccination, while 30 out of 46 participants remained negative.
These results show that a significant proportion of healthcare workers (29%, 22 out of 77) developed de novo autoantibody production after receiving three doses of mRNA-based anti-SARSCoV-2 vaccines. The production of de novo ANA was detected in 6 out of 77 (8%) participants following the administration of two doses, and in 16 out of 77 (21%) participants following the administration of three doses of vaccine. According to these results, the percentage of positivity for ANA correlates with the number of vaccinations. Interestingly, the positivity that developed after the second vaccination was maintained over time.
Additionally, researchers analyzed five ANA patterns: homogeneous, speckled, cytoplasmatic, nucleolar, and other patterns (e.g., midbody, centrosomes, spindle poles). After the second dose of vaccine, the homogeneous pattern was observed in 5/6 samples, the speckled in 4/6 and the cytoplasmatic in 1/6. After the third dose of vaccine, the homogeneous pattern was observed in 12/21, speckled in 6/21, nucleolar in 2/21, cytoplasmic in 1/21 and other patterns in 7/21. These findings indicate that the homogeneous pattern was the most prevalent. As the homogeneous pattern is commonly associated with the presence of anti-double stranded DNA, anti-nucleosome, and anti-histone autoantibodies, all samples that were found to be positive for the homogeneous pattern after the second vaccination were tested for these autoantibodies. The results were negative.
The analysis of other autoantibodies revealed that only anticardiolipin and anti-alpha smooth muscle actin antibodies showed a slight increase after the second vaccination, but this increase was not statistically significant.
The authors stated that these preliminary results support the hypothesis that overstimulation of the immune system could lead to an autoinflammatory mechanism and eventually to autoimmune diseases. As positive test for ANA is not indicative of an autoimmune disease, they intend to follow the participants with de novo autoantibody production after mRNA-based anti-SARSCoV-2 vaccination to determine whether they show clinical signs of autoimmune disease. The researchers suggested that the observed association between anti-SARS-CoV-2 vaccination and positive test for ANA needs further investigation.
This article was published in Autoimmunity.
M.C Sacchi,et al. The onset of de novo autoantibodies in healthcare workers after mRNA based anti-SARS-CoV-2 vaccines: a single centre prospective follow-up study. Autoimmunity, 2023; 56:1, 2229072. https://www.tandfonline.com/doi/full/10.1080/08916934.2023.2229072