Abstract

Biologics targeting the interleukin5 (IL5) have profoundly changed the management of severe asthma patients. Recently, caution was raised about rheumatological diseases induced by anti-IL5 therapies (Kawabata, J Asthma Allergy, 2021).

We report a series of 9 patients presenting with onset or worsening of rheumatological diseases following the initiation of anti-IL5 therapies (mepolizumab n= 6, benralizumab n= 3).

Patients were all-but-one female (mean age 62±12), with late-onset eosinophilic severe asthma on continuous oral corticosteroids (CS) (mean 15 mg/day). All of them were good responders to the anti-IL5 therapy. Rheumatologic diseases appeared (n=6) or deteriorated (n=3) 9 months (0-27) after initiation of biologic. All patients had specialized evaluation, with several diagnosis: unclassified chronic inflammatory rheumatism n=4; polyarthralgia n=3; intermittent oligo-arthritis n=1: rheumatoid arthritis n=1. All required repeated oral or intravenous courses of CS. 4 patients had severe erosive disease, 3 required additional immunosuppresive therapies. The biologic was stopped in 2 patients, without improvement.

Temporal relationship between drug initiation and onset of erosive arthritis supports the role of anti IL5 in rheumatological disease. An animal model of asthma and arthritis demonstrated that eosinophils were strongly involved in arthritis resolution, an effect that was abolished by anti IL5 drug (Andreev, Ann Rheum Dis, 2020). However, since symptoms occurred after complete steroids withdrawal in 6/9 patients, we cannot rule out that some patients in our series could have a preexisiting disease.

Larger series are needed to assess the role of anti IL5 therapies on arthritis.