Rituximab is a type I anti-CD20 monoclonal antibody, which is primarily used for treating non-Hodgkin's B cell lymphoma [1]. Clinical efficacy, safety, and modulating effects on normal, malignant pre-B and mature B cells have been reported [2]. It is also used off label in the treatment of several autoimmune diseases. Common side effects are infusion-related reactions, such as fever, chills, and shivering, which occur frequently after the first infusion and usually related to cytokines release [3].