We report a 37-year-old female HTLV-I carrier with complicating primar
y biliary cirrhosis (PBC) and mixed connective tissue disease (MCTD).
Serum anti-HTLV-I antibody titer was x256. Flower cells (4.5%) were fo
und in the peripheral blood. Southern blot analysis showed no clonal i
ntegration in peripheral blood lymphocyte (PBL) DNA. Polymerase chain
reaction showed the HTLV-I genome in PBL DNA. As cholestatic liver dys
function and serum titer of anti-mitochondrial antibody were found, a
clinical diagnosis of PBC was made. This patient later developed MCTD.
These diseases responded well to prednisone. The pathogenetic relatio
nship of HTLV-I infection with various autoimmune diseases is discusse
d.