PRTN3 and kidney disorder: Although the number of PR3 positive patients was small, this study found a higher frequency of pulmonary and renal disease in PR3 positive cases than in MPO+ cases, and that leptomeningeal and parenchymal involvement in the brain were more common in PR3 positive hypertrophic pachymeningitis compared with MPO positive and idiopathic hypertrophic pachymeningitis.