A case of asymptomatic Sjögren's syndrome who developed interstitial pneumonia during monoclonal antibody therapy of Crohn's disease

A 67-year-old woman was diagnosed with ileocolic Crohn's disease at 61 years of age. Remission had been induced by the monoclonal antibody adalimumab, and maintenance therapy had continued since her diagnosis. However, she developed respiratory symptoms, including a dry cough. A chest CT scan revealed interstitial shadows in the lower pulmonary lobes. Although no sicca symptoms were noted, she was serologically positive for both anti-Sjögren's syndrome-related antigen A and B antibodies, and salivary gland biopsy showed lymphocytic infiltration. Consequently, she was diagnosed as having asymptomatic Sjögren's syndrome. Infection or drug-induced pulmonary disease was considered unlikely, and the interstitial pneumonia was considered an extra-glandular presentation of Sjögren's syndrome. Thus, interstitial shadows, which appear during immunotherapy for Crohn's disease, could indicate asymptomatic Sjögren's syndrome; clinicians should consider this rare clinical picture when assessing such a patient.