Development of Rheumatoid Arthritis During Anti-Interleukin-5 Therapy in a Patient with Refractory Chronic Eosinophilic Pneumonia

Abstract

Purpose: To report the case of a patient with refractory chronic eosinophilic pneumonia who developed rheumatoid arthritis during anti-interleukin (IL)-5 therapy.

Case report: The case of a 66-year-old male ex-smoker with allergic rhinitis who had dyspnea and chronic cough for 6 months and who was ultimately diagnosed with chronic eosinophilic pneumonia is reported. Long-term corticosteroid therapy was necessary due to recurrence of the chronic eosinophilic pneumonia during tapering of the corticosteroid. As a steroid sparing strategy, mepolizumab was initiated, and the steroid was tapered gradually. When the dose of prednisolone was 2 mg/day, he developed polyarthralgia. Mepolizumab was changed to benralizumab considering the possibility that arthralgia was a side effect of mepolizumab; however, the arthralgia continued and he was ultimately diagnosed with rheumatoid arthritis. Methotrexate was initiated and his arthritis improved. Thereafter, benralizumab was discontinued after 5 injections, and he subsequently required neither systemic corticosteroids nor biologics.

Conclusion: The present case may suggest that suppression of IL-5 induces rheumatoid arthritis in certain patients; however, it is also possible that initial steroid therapy improved subclinical RA and made it remain undiagnosed, and the parallel OCS tapering during IL-5 therapy could have contributed to unveil the underlying RA. Further studies are required to establish guidelines on the optimum use of anti-IL-5 therapy and to understand the interactions between chronic eosinophilic pneumonia, anti-IL-5 therapy, tapering of corticosteroid and development of rheumatoid arthritis.

Keywords: asthma; benralizumab; chronic eosinophilic pneumonia; mepolizumab; rheumatoid arthritis.

Figure 1

(A, B) Chest X-ray and chest CT scan in October 2012. Patchy infiltrations predominantly around the pleura with air bronchograms in the left upper lobe are seen. (C, D) Chest X-ray and chest CT scan in February 2013. Dramatic improvement is seen. (E, F) Chest X-ray and chest CT scan in April 2013. Relapse of CEP showing infiltration in right upper lobe is shown. (G) Chest X-ray in August 2015. Infiltrative shadow in left lower lung field is seen.

Figure 2

Clinical course of the patient. Oral prednisolone to control CEP was tapered off during mepolizumab therapy. Methotrexate was initiated for rheumatoid arthritis and mepolizumab was replaced by benralizumab. No exacerbations were noted after the discontinuation of benralizumab. The degree of respiratory symptom (*green) and arthritis (**blue) are indicated.