Use of methotrexate in ANCA-associated vasculitides.

Since the introduction of combined immunosuppressive therapy consisting of oral cyclophosphamide (CYC) and glucocorticosteroids (GC) in the 1970s, the outcome of antineutrophil cystoplasmic antibodies (ANCA)-associated vasculitides has improved dramatically over the last decades. However, the long-term follow-up of patients treated with CYC plus GC has revealed a high treatment-related morbidity and mortality and a high proportion of patients suffering from relapses (up to 50%), requiring CYC and GC again. Methotrexate (MTX) can replace CYC for induction of remission in patients with a non life-threatening disease course of ANCA associated vasculitides ('early systemic'). Furthermore, MTX can be used as a maintenance medication after induction of remission with CYC (plus GC), provided there is a decent renal function with a GFR >50 ml /min. As with any maintenance regimen, we do not know exactly for how long to continue MTX maintenance therapy. When using MTX as remission induction or maintenance regimen a tight control of urinary sediment and kidney function is mandatory in order to detect a potential renal relapse or de novo manifestation.