Schnitzler syndrome co-occurring with idiopathic multicentric Castleman disease that responds to anti-IL-1 therapy: A case report and clue to pathophysiology

A forty-four year old woman with a history of a recurrent urticarial rash, presented to our hospital complaining of 6 months of night sweats, fever, chronic urticaria, iliac bone pain, and generalized lymphadenopathy. An IgM Kappa monoclonal component was measured at 7.8 g/L. A lymph node biopsy revealed histopathological features consistent with the plasma cell variant of iMCD. She was diagnosed with SS and iMCD. Anti-IL-1 treatment with anakinra (100 mg/day) was introduced. Within 48 h, we observed improvement in the fever and the urticarial rash. By one month, we considered the patient in complete remission. Two years later, the remission is persistent while the patient is still under therapy. Though this is only the fourth reported case of anakinra in iMCD, this is yet another case demonstrating the effectiveness of anti-IL-1 blockade in SS. We hypothesize that uncontrolled cytokine production is responsible for both the SS and the iMCD. The etiologies of SS and iMCD are unknown, and future research is necessary.