Aendekerk JP, Timmermans SAMEG, Busch MH, et al. - Given that urinary soluble CD163 has been recognized as a promising marker of active ANCA-associated GN but previous studies are limited by the lack of histologic data, and therefore, researchers herein analyzed 95 patients experiencing ANCA-associated vasculitis who underwent a kidney biopsy. These patients were analyzed for urinary soluble CD163. Overall experts examined 125 kidney tissue sections (first kidney biopsy, n = 67; repeated biopsy, n = 58) with concurrent 24-hour urine samples. They detected high concentrations of urinary soluble CD163 in 96 (87%) of 110 biopsies with active ANCA-associated GN vs one (7%) of 15 biopsies without active ANCA-associated GN and one (6%) of 17 healthy controls. In repeated biopsies, better sensitivity (0.94) and specificity (0.91) of urinary soluble CD163 for detecting relapsing ANCA-associated GN appeared when compared with routine clinical measures. Overall, findings demonstrated a link of urinary soluble CD163 with active ANCA-associated GN, and also urinary soluble CD163 correlated with histologic characteristics as noted in ANCA-associated GN.