Kronbichler A, et al. - In patients with antineutrophil cytoplasm antibody-associated vasculitis (AAV) who were treated with rituximab, researchers evaluated the risk factors for the development of severe infection. They found that ~25% of patients with AAV receiving rituximab had severe infections; this risk, however, was reduced by trimethoprim–sulfamethoxazole prophylaxis. Severe respiratory infections, bronchiectasis, and endobronchial involvement, especially, were found to be risk factors. When analysis was restricted to respiratory tract infections, a higher risk was conferred by endobronchial involvement, severe bronchiectasis, higher neutrophil count, and major relapse as indication for rituximab use, while a lower frequency of severe infections was observed in refractory disease as indication.