Delayed response of oral pemphigus vulgaris to rituximab treatment.

Rituximab is a monoclonal antibody directed against the CD20 antigen of B cells, which has been developed for the treatment of lymphomas and has been successfully used in the treatment of recalcitrant pemphigus vulgaris. Here, we report on a 26-year-old patient with an 18 month history of pemphigus vulgaris of the oral mucosa where treatment with rituximab led to a delayed but sustained therapeutic response. This case is of interest since most of the previous reports have described a more rapid clinical improvement of refractory pemphigus by rituximab treatment. The delayed clinical response to rituximab of the present case may be explained by the persistence of long-lived plasma cells that continued to produce pathogenic autoantibodies against desmoglein 3.