A case of organizing pneumonia induced by tocilizumab.

A 66-year-old woman rheumatoid arthritis was treated with methotrexate and tocilizumab. Chest radiography revealed bilateral consolidation of an upper lesion in the lung. Laboratory data indicated a hepatic disorder and increased eosinophils. Transbronchial lung biopsy specimens showed organizing pneumonia. Infection was unfavorable based on culture and PCR. Drug lymphocyte stimulation test showed positive results both for methotrexate and tocilizumab. We were concerned that her pneumonitis was drug-induced. And the symptoms appeared after the infusion of tocilizumab. Here, we report a case of tocilizumab-induced organizing pneumonia.