Abstract: Objective To investigate the immunofluoresce nt and immunoblotting features of paraneoplastic pemphigus(PNP).Methods Sera were tested by indirect immunofluorecence(IIF)and immunoblotting(IB)in four patients with PNP.Results Binding of IgGand C3 to the intercell ular spaces of epidermis was found in IIF with rat bladder as substrate.The titers decreased after the excision of tumo rs.The autoantibodies also bound to substrates of the epithelia of human skin,rat tongue and esophagus in those p atients.The patients' sera recogni zed 210kD and 190kD antigens from human kera tinocyte extracts with IB analysis.Conclusions IIF with rat bladder as substrate can be used a screening test for PNP.PNP tends to involve epithelia of mucosa.The results of IB test m ay confirm the diagnosis of PNP of the 4 patients.

Key words: Pemphigus,paraneoplastic, Fluorescent antibody technique,indirect, Immunoblotting