Abstract
The antibodies to 2 types of intermediate filaments (IFs), vimentin and cytokeratin filaments, were assayed by western blotting in sera from 148 patients with connective tissue diseases and from 36 patients with infectious diseases. IFs were isolated from human embryonic lung fibroblast, HEL-299 and epithelial cell line, PtK-2. The antibodies to vimentin filament from HEL-299 cell were found in 29% of 82 patients with rheumatoid arthritis (RA), 54% of 35 patients with polymyositis-dermatomyositis (PM-DM) and 39% of 31 patients with progressive systemic sclerosis (PSS). The frequencies of antibodies to cytokeratin filament from PtK-2 cell were 30%, 46% and 45% in RA, PM-DM and PSS, respectively. The frequencies of those antibodies detected by western blotting were higher than those by immunofluorescence using PtK-2 cells as substrate. The frequencies of antibody to vimentin and cytokeratin in 36 patients with infectious diseases were 58% and 22%, respectively. These antibodies belonged mainly to the IgG class. No healthy volunteer had anti-IFs antibody. The vimentin antibodies positive patients with RA and PSS had frequently lung fibrosis. The presence of IFs antibodies in patients with both connective tissue diseases and infectious diseases might suggest the relationship between these two disorders.
