[A case of lymphocytic interstitial pneumonia with Sjögren's syndrome and systemic lupus erythematosus in which human herpes virus-6 infection was the suspected pathogen].

A 47-year-old-woman was admitted to our hospital complaining of thirst and dry cough after catching cold. Sjögren's syndrome (SjS) and systemic lupus erythematosus (SLE) were diagnosed. Chest X-P and CT findings suggested strongly that she had interstitial pneumonia. Thoracoscopic lung biopsy was therefore performed, and the biopsy specimens showed marked infiltration of small lymphocytes and of plasma cells into the alveolar walls and interlobular septa. Since the infiltrating cells were not atypical and gene analysis did not show mono-clonality, we made a diagnosis of lymphocytic interstitial pneumonia (LIP). Because the patient's symptoms appeared only after she caught cold, we suspected that virus infections were somewhat involved in the etiology of these diseases. The level of human herpesvirus-6 (HHV-6) antibody was high, and furthermore, HHV-6 was detected using the polymerase chain reaction from lung biopsy specimens. We suspected in this case that LIP, SjS, and SLE had appeared concomitantly after an active HHV-6 infection.