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.