Specific antibody activity against neuroendocrine tissue in a case of POEMS syndrome with IgG gammopathy.

Specific antibody binding activity directed against pituitary tissue was demonstrated in a typical case of POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome with paraproteinemia of IgG lambda type. IgG binding against various other tissues could not be detected by immunoelectroblotting and immunocytochemistry. We propose that POEMS syndrome is an antibody-mediated immune disorder, in which the hypophysis is the primary target of the pathologic myeloma antibodies. The immunopathogenetic lesion of the hypophysis could induce secondary disturbances of other organs, thus explaining the multisystemic disorder.