Letter to the editor regarding the article ‘‘Patil S, Patil A. Systemic lupus erythematosus after COVID‐19 vaccination: A case report. J Cosmet Dermatol. 2021 Aug 21. 10.1111/jocd.14386

• Published in: Journal of Cosmetic Dermatology 2021-12, Vol.20 (12), p.4076-4077
• Main Authors: Abdullah, Lina, Awada, Bassem, Kurban, Mazen, Abbas, Ossama
• Format: Article
• Language: English
• Subjects: COVID-19; COVID-19 Vaccines; COVID‐19 vaccine; Humans; interferon; Letters to the Editor; lupus; Lupus Erythematosus, Systemic; plasmacytoid dendritic cell; SARS-CoV-2; Vaccination - adverse effects
• ISSN: 1473-2130; 1473-2165
• DOI: 10.1111/jocd.14572

While the vital role IFN-Is and pDCs play in SLE pathogenesis is well-established, it has recently been demonstrated that IFN-Is, and pDCs play a significant role during COVID-19 infection or vaccination.4 Characterized by plasma cell morphology and by expressing HLA-DR, CD4, BDCA-2, CD123, and Toll-like receptor (TLR)9 and TLR7 in endosomal compartments, pDCs are peculiar DC subset that play a vital role in innate immunity through their ability to sense nucleic acids via their TLRs.4-6 Upon TLR7/9 activation, pDCs produce substantial amounts of IFN-Is that is chiefly involved in antiviral immunity. [...]pDCs are the most potent producers of IFN-Is, which, in turn, are crucial cytokines in controlling viral replication by inducing the expression of numerous genes leading mostly to an antiviral state.5, 6 pDCs also contribute to the adaptive immunity regulating the function of other immune cells. Coronaviruses, including COVID-19, have been shown to be effective stimulators of pDCs leading to strong IFN-I induction.4 Similarly, COVID-19 vaccines, including mRNA (such as Pfizer and Moderna) and AdV (DNA delivered within non-replicating recombinant adenovirus vector systems such as AstraZeneca, Sputnik V, COVISHIELD, and Johnson and Johnson) vaccines, provoke immunity to COVID-19 by producing high levels of spike proteins.7, 8 While mRNA vaccines interact with various endosomal (especially TLR7) and cytosolic cellular innate sensors (inflammasome components), AdV vaccines interact with multiple pattern-recognition receptors, particularly TLR9.7 Despite these differences, both vaccine types converge on IFN-I production which partly occurs through pDC-mediated innate immune response. 5-8 Upon activation and increased production, IFN-Is and pDCs may then play a significant pathologic role in the development of various autoimmune diseases including SLE after COVID-19 vaccination.5, 9 In SLE, the main IFN-I producers have been identified as the pDCs and immune complexes composed of autoantibodies and nuclear antigens are capable of activating pDCs in a TLR-dependent way.