The levels of IL-6 (p = 0.015), IL-21 (p = 0.022), IL-27 (p = 0.001), and IL-33 (p\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\le$$\end{document}≤ 0.001), were increased in PAP lesions compared to healthy bone (Fig. 2a). Here, IL6 is linked to pulmonary alveolar proteinosis.