Exacerbation of paraneoplastic pemphigus by cyclophosphamide treatment: detection of novel autoantigens and bronchial autoantibodies

A 48-year-old woman with a follicular, grade III, B-cell non-Hodgkin lymphoma developed clinical, immunopathological and histological features of paraneoplastic pemphigus. The skin symptoms flared after repeated cyclophosphamide infusions, and were preceded and accompanied by a progressive dyspnoea. Although the skin and oral mucosal disease went into remission with high-dose steroid and intravenous immunoglobulin therapy, the severe alveolitis led to death. Immunoblotting of human epidermal extracts showed that the patient's serum IgG reacted with the 210-kDa envoplakin, 190-kDa periplakin, as well as the recombinant protein of BP180 NC16a domain. IgG and IgA enzyme-linked immunosorbent assays for desmoglein 3 were positive, too. Indirect immunofluorescence studies on COS-7 cells transiently transfected with desmocollin 1-3 cDNAs showed that the patient's serum contained IgG and IgA antibodies to desmocollin 3 as well as IgG antibodies to desmocollin 2. Serum IgG and IgA strongly stained rat bronchial epithelium, corresponding to autoantibodies possibly involved in the pathomechanism of the severe lung disease. In this case, which was characterized by a mixed IgA/IgG antibody panel displaying known and unique antigenicity, the serious episodes of paraneoplastic pemphigus flared after cyclophosphamide treatment.