IL-6 Blockade As a Steroid-Sparing Treatment for Rhupus Patients

Overlap of Rheumatoid Arthritis (RA)  and Systemic Lupus Erythematosus (SLE) is a rare clinical condition that was first described in 1974 as Rhupus. Rhupus is a rare clinical entity with a prevalence of about 0.09%. The main differential diagnoses include RA with extra-articular manifestations, SLE with rheumatoid-like articular lesions, and mixed collagenous tissue disease.  Some Authors consider Rhupus to be an overlap condition of polyarthritis and SLE, since anti-CCP antibodies (which are highly specific for RA) and anti DNA /Sm (which are highly specific for SLE) coexist in Rhupus.

Therefore, diagnosis of Rhupus bases on the combination of inflammatory symmetrical erosive polyarthritis and clinical features of SLE. Recognition of these patients is important, since  therapy and outcome differ from patients having RA or SLE alone.

For patients whose disease is resistant to or dependent on corticosteroids, methotrexate (MTX) and azathioprine (AZA) has been used as steroid-sparing second-line treatment with conflicting results. While MTX seemed to be effective in controlling symptoms, data on AZA remain controversial, while the TNF-blocking agents Infliximab and Etanercept have been shown to be unable to induce and maintain disease remission.

IL-6 could play an important role in the pathogenesis of Rhupus. Indeed, IL-6 levels are elevated in active disease.

We are reporting on three women 59, 51 and 46 year-old with refractory Rhupus (disease duration of 14, 19 years and 13, respectively) who were at high risk for long lasting high dose of CS, and were successfully treated with humanised anti-IL-6 receptor antibody, Tocilizumab, given monthly  at the dose of 8 mg/kg.