Kronbichler A, et al. - Experts evaluated the risk factors for the development of severe infection in patients with antineutrophil cytoplasm antibody-associated vasculitis (AAV) receiving rituximab. One-quarter of patients with AAV had severe infections. The risk was reduced with trimethoprim–sulfamethoxazole prophylaxis, while risk factors for severe respiratory infections were especially bronchiectasis and endobronchial involvement. A higher risk was conferred by endobronchial involvement, severe bronchiectasis, higher neutrophil count and major relapse as indication for rituximab use when analysis was restricted to respiratory tract infections. A lower frequency of severe infections was seen in refractory disease as indication.