Spike protein in the skin after COVID-19 vaccination
A 64-year-old man with active rheumatoid arthritis (RA) developed painful skin eruptions in both legs and hands 13 days after the first dose of mRNA COVID-19 vaccination, BNT162b2. The lesions were exacerbated after the second dose of BNT162b2 vaccination, although he did not have a fever or any systemic symptoms. Laboratory examination revealed no remarkable change in blood counts, liver, or renal function except for mild increase of d-dimer suggesting abnormal coagulation.Biopsy from the necrotic nodule in the left popliteal fossa revealed necrotic epidermis and underlying occlusive vasculopathy in the middle to deep dermis with inflammatory infiltrates with neutrophils, leukocytoclasia, fibrin exudation, extravasated erythrocytes, and microthrombi (see panels B and C in the Figure). Also, there were lymphocytic infiltrates into the subcutaneous fat tissue (panel D). Histological diagnosis of necrotizing vasculitis was made. In 88 day of the disease onset, some of the vesicopapular lesions turned to be necrotic nodule be necrotic nodules and groups of vesicles on red macules newly developed in the both legs. Varicella Zoster Virus (VZV) was suspected. Immunostaining with anti-VZV was positive for the degenerated keratinocytes in the vesicle, making a final diagnosis of VZV infection. It was also confirmed with PCR using extracted DNA from two biopsied specimens taken at the early and late stages of 2-month intervals, that is, necrotic nodules and vesicles, respectively. Immunostaining with anti-coronavirus spike protein (SP) antibody revealed the SP expression in the intravesicular cells in the epidermis and endothelial cells of the inflamed vessels in the dermis. The SP was also found in the endothelial cells of venules in the subcutaneous fat tissue underlying the herpetic vasculitis lesion.