Mixed connective tissue disease and Sjögren's syndrome, accompanied by HTLV-I infection

A 48-year-old Japanese woman with mixed connective tissue disease (MCTD) and Sjögren's syndrome (SjS) was a carrier of HTLV-I and had anti-HTLV-I antibodies in her serum. Moreover, her peripheral blood lymphocytes contained proviral DNA for the pX region of HTLV-I as detected by the polymerase chain reaction. An immunohistological study was performed on her minor salivary gland to detect gene products of HTLV-I (P19 and P28 proteins); specific staining was demonstrated only in the epithelium of the salivary ducts. HTLV-I and its associated immune dysfunction may be responsible for MCTD and SjS in this patient.