Response of pemphigus vulgaris to anti-CD20 antibody therapy (rituximab) may be delayed.

Abstract

Conflict of interest: none declared. Recent reports have documented swift responses in refractory pemphigus vulgaris to anti‐CD20 antibody therapy (rituximab).1, 2 We report a case in which improvement was delayed following an initial exacerbation. A 37‐year‐old woman presented with a 4‐month history of blisters affecting the trunk, vagina and mouth. The clinical diagnosis of pemphigus vulgaris was confirmed by histology and direct immunoflorescence. Prednisolone (up to 2 mg/kg daily) either alone or in combination with azathioprine (up to 3 mg/kg daily), mycophenolate mofetil (up to 5 g daily), ciclosporin (up to 6 mg/kg daily) or cyclophosphamide (up to 2 mg/kg daily) failed to control her disease over 2.5 years. Intermittent 5‐day infusions of intravenous immunoglobulins (400 mg/kg daily) and intravenous methylprednisolone pulses (1 g daily for 3 days) were only partially effective. In an attempt at better disease control, an anti‐CD20 antibody therapy (rituximab) was administered (375 mg/m2) once weekly for 4 weeks with oral paracetamol and intravenous chlorpheniramine maleate pre‐medication. This produced an immediate exacerbation of her pemphigus despite concomitant prednisolone (14 mg daily) and mycophenolate mofetil (4 g daily), necessitating a 3‐day course of pulsed intravenous methylprednisolone (1 g daily). The exacerbation was not associated with any significant change in antiepidermal antibody titres.