[Renal manifestation in ANCA-associated vasculitis]

In patients with ANCA-associated vasculitis renal involvement is frequently seen and the severity of renal manifestation is very important for therapeutic strategies and prognosis. Clinically rapid loss of renal function, nephritic sediment and proteinuria in a non-nephrotic range are characterizing a focal segmental necrotizing pauci-immune glomerulonephritis with extrarenal proliferations. Induction treatment depends on the severity of manifestations. With a normal renal function methotrexate can be used in combination with steroids. In patients with organ threatening involvement but creatinine below 500 µmol/l cyclophosphamide pulses or Rituximab should be used together with steroids, initially with i. v. pulses. Rituximab is more effective in PR3-ANCA vasculitis and should be used in relapsing disease, in young patients to avoid gonadal toxicity and in patients with an increased risk of malignancies. In patients on dialysis or with creatinine > 500 µmol/l plasma exchange should be added. Maintenance treatment (mainly with azathioprine) is necessary as at least 50 % of the patients develop relapses. Rituximab seems more effective, however it is not approved for maintenance treatment and no long-term data are available. Adjuvant treatment, long-term side effects and the increased incidence of cardiovascular events have to be included in the follow-up of vasculitis patients. In end-stage renal disease patients relapses occur but are more difficult to diagnose and treat with higher incidence of infections. Transplantation should be offered as patient and transplant survival is good.