Thrombotic microangiopathy induced by long-term interferon-β therapy for multiple sclerosis: a case report.

We report the case of a 53-year-old woman treated for 8 years with Betaferon® (interferon-β-1b), who developed mild renal failure with hypertension, proteinuria and glomerular hematuria. Kidney biopsy was consistent with thrombotic microangiopathy (TMA). Considering the strong evidence of interferon-α causing TMA and the numerous immunomodulatory activities shared by INF-α and -β, we incriminated Betaferon as the etiological agent of TMA in our patient. To our knowledge, it is the first time such an association has been published.