PTX3 and autoimmune disease: The presence of preformed PTX3 in neutrophil granules [14], similar to MPO and PR3 [15, 16], and the detection of circulating anti-PTX3 aAbs in other autoimmune disease such as systemic lupus erythematosus [17, 18], lead us to investigate whether anti-PTX3 aAbs could be detected in the sera of AAV patients.