CD8A and psoriasis: Reduced humoral and cellular immune response (CD8 +) to COVID-19 mRNA vaccines were found by Haberman et al. in IMID treated with methotrexate and by Mahil et al. in psoriasis (47% and 62% responders, respectively) [23, 25], although this finding has not been confirmed in our and other studies (> 80% responders) [14, 21, 22, 26].