Iguratimod-induced acute interstitial pneumonia with hypogammaglobulinemia in a rheumatoid arthritis patient

Abstract

Iguratimod is a novel disease modifying anti-rheumatic drug for rheumatoid arthritis (RA), whose mechanism of action is considered to be the inhibition of the production of inflammatory cytokines and immunoglobulins. Iguratimod might induce interstitial pneumonia (IP) as a side effect, although its detailed clinical course has not been described. We report a case of a 79-year-old female RA patient who developed acute IP and hypogammaglobulinemia after 14 months of iguratimod treatment. Immediate cessation of iguratimod followed by steroid pulse and high-dose corticosteroid therapy rapidly improved her respiratory function. As the chest computed tomography images taken seven months before onset had no sign of IP and 50 mg/day of iguratimod was the only drug she was taking at the onset, the causal relationship between iguratimod and IP was strongly suggested. Respiratory symptoms and lung images should be routinely monitored while using iguratimod for early detection of iguratimod-induced IP, even after long-term administration for more than one year as in this case. Monitoring of immunoglobulin levels might also be useful, as hypogammaglobulinemia seemed to be a predictor of IP occurrence in this case and other cases previously reported.

Keywords:

• Iguratimod
• interstitial pneumonia
• rheumatoid arthritis
• steroid therapy
• hypogammaglobulinemia

Conflict of interest

K.Y. received financial support or fees from AbbVie, Astellas, BMS, Daiichi-Sankyo, MitsubishiTanabe, Pfizer, Sanofi, Santen, Takeda, Teijin, Boehringer Ingelheim, Chugai, Eisai, Ono, Taisho Toyama, UCB, Immuno Future, Asahi Kasei and Janssen. K.F. received financial support or fees from Astellas, BMS, Daiichi-Sankyo, MitsubishiTanabe, Pfizer, Santen, Takeda, Chugai, Eisai, Taisho Toyama, UCB, and Janssen. All other authors declare no competing financial interests.