Use of anti-neurofilament antibody to identify paired-helical filaments in inclusion-body myositis.

Paired-helical filaments (PHFs) are an important diagnostic criterion of the inclusion-body myositis (IBM) muscle biopsy; but, until now, their presence could be identified only by electronmicroscopy. In this report, we describe an easy immunocytochemical procedure, utilizing commercially available antibody, that enables reliable identification of muscle PHFs by light microscopy. This procedure greatly facilitates diagnosis of IBM.