Late-onset methotrexate-induced pneumonitis with neutrophilia in bronchoalveolar lavage fluid.

A 61-year-old woman being treated with methotrexate (MTX) 8-10 mg/week and prednisolone 2.5 mg/day for rheumatoid arthritis presented with a 1-week history of increasing fever and dry cough. The patient deteriorated with administration of antibiotics. Chest CT scan showed bilateral diffuse ground-glass opacities. Analysis of bronchoalveolar lavage fluid (BALF) revealed marked neutrophilia (65.2% of total cells). The specimen from transbronchial lung biopsy showed a non-specific interstitial pneumonia pattern. Following withdrawal of the MTX, her pulmonary infiltration, clinical symptoms and laboratory findings gradually improved. Therefore, she was diagnosed as having MTX-induced pneumonitis. Lymphocytosis in BALF has been identified as a characteristic of MTX-induced pneumonitis, particularly in late onset of this disease. However, the BALF in our patient was neutrophilic. Although neutrophilia in BALF of patients with drug-induced pneumonitis is usually associated with poor outcome, rare cases of good outcome do exist.