Thus, the investigators aim to investigate whether rituximab can reduce glucocorticoid dose in induction remission in ANCA-associated vasculitis (to show non-inferiority for efficacy between low-dose and high-dose glucocorticoid plus rituximab). Participants will be randomised to the "low-dose glucocorticoid plus rituximab" or the high-dose glucocorticoid plus rituximab" groups. Primary endpoint is proportion of remission at 6 months, then data regarding relapse and long-term safety will be collected until 24 months.