REDUCED COVID-19 VACCINE RESPONSE IN PATIENT TREATED WITH DUPILUMAB FOR IGG4 RELATED DISEASE.

INTRODUCTION: Dupilumab is a novel anti-interleukin-4 (IL-4) receptor-α monoclonal antibody that targets the signaling pathways of IL-4 and IL-13. There there has been limited data about adequate humoral immune response after vaccination to SARS-CoV-2 in patients on dupilumab. CASE DESCRIPTION: We previously reported the case of a 71-year-old man with IgG4 related-disease (IgG4-RD) that we successfully treated with dupilumab. This patient was followed while his IgG4-RD remained well controlled on dupilumab which he remained on during this pandemic. He received two Pfizer SARS-CoV-2 mRNA vaccinations on March 24 and June 18, 2021. On July 24, 2021, result of SARS-CoV-2 Total-Antibody was non-reactive. As such, a third booster vaccination on November 10, 2021 and timing of holding dupilumab was made to optimize his potential immune response. Dupilumab was held for 1 month prior to his third vaccination and was re-initiated two weeks post-vaccination. On December 3, 2021, his SARS-CoV-2 Total-Antibody was repeated and found to be 2282 U/ml while his SARS-CoV-2-NPROT Total-Antibody was negative, implying immune response through vaccination and not natural exposure. DISCUSSION: To our knowledge, this is the first case report on a patient with IgG4-RD controlled on dupilumab who was found to have adequate vaccine response after his dupilumab was held for 1 month after failing to mount a response to the first two vaccination doses while on therapy. As there is evidence that lower vaccine-specific titers afford less protection against COVID-19, this report highlights this approach as one possible strategy for protecting these individuals who may remain at high risk.