TNF and rheumatoid arthritis: It is worth noting that we found a significantly increased risk of HZ in RA patients receiving therapy with rituximab, which is a monoclonal antibody targeting CD20 of B lymphocytes and affects cellular immunity.40 Rituximab has been approved for the treatment of RA patients who have failed to respond to 1 or more anti‐TNF‐α agents.41 Therefore, we thought that patients who received rituximab therapy may have a severe RA with worse cellular immunity, which may explain the increased risk of HZ in these patients.