AUTOANTIBODY TO INTERMEDIATE FILAMENTS IN INFECTIOUS-MONONUCLEOSIS

By employing indirect immunofluorescent staining we detected autoantibodies against circulating lymphoblasts in the sera of two patients with acute infectious mononucleosis (IM). The target structures were identified as intermediate filaments (IMF) by their antigenic and biochemical properties. High titers of anti-IMF autoantibody were detected in 32 of 48 (67%) IM patient sera but not in control sera. The antibodies were usually of IgM class. The presence of anti-IMF antibodies did not correlate with anti-smooth muscle antibodies, and absorption studies revealed that the specificity of these antibodies differed from that of heterophilic (Paul-Bunnell) antibodies. The results may be interpreted as suggesting that the rapid turnover of lymphocytes in IM may be associated with a release of autoimmunogenic cytoplasmic intermediate(-sized) filaments. © 1979.