Background
Monoclonal antibodies have been used for the modulation of immune responses in several disorders, including cancer, autoimmune, and infectious diseases. 1
Rituximab (RTX) is a chimeric monoclonal antibody that specifically binds to the B-cell surface antigen CD20 which mediate cytotoxicity in these cells. 2-4 The mechanism of action of RTX including, regulating cell-cycle signaling, inducing apoptosis, improving cytotoxic drugs cells’ sensitization, antibody-dependent cellular, and complement-mediated cytotoxicity. 4
RTX is used in the management of previously untreated or treated adults with CD20+ chronic lymphocytic leukemia (CLL) 5, granulomatosis with polyangiitis 6, microscopic polyangiitis 7, non-Hodgkin lymphomas8, pemphigus vulgaris 9, rheumatoid arthritis 10, and other off-label uses such as acquired thrombotic thrombocytopenic purpura 11, Waldenström macroglobulinemia 12, refractory autoimmune hemolytic anemia 13, etc.
As a monotherapy, RTX (1000 mg) is administered weekly for one month or every 3 to 4 weeks when used in combination with chemotherapy.14
Pemphigus is one of the autoimmune diseases which characterized by cutaneous blisters and erosions and mediated by autoantibodies. Pemphigus Vulgaris (PV) is the major progressive subtype of pemphigus and may lead to death if it is not treated. 15
The adverse events of RTX might be early (e.g., fever, cough, and dyspnea), or late such as agranulocytosis or severe infection.16
Serum sickness is an uncommon hypersensitivity undesirable reaction due to antigens, characterized by fever, rash, and arthralgia.17 RTX is induce serum sickness by producing human anti-chimeric antibodies. 18 Although serum sickness is commonly reported in patients with autoimmune disease, few reports were published for patients with PV.