C5AR1 and Langerhans cell histiocytosis: Based on the protein data, we identified seven cell populations in LCH lesions: CD141+DC1, cDC2 which comprised CD5+DC2 and CD5-DC3, CD141+CD123+pre-DC/AS DC, CD123+pDC, CD88+CD14+ monocytes, and CD1a+CD207+ LCH cells (Fig. 1B and Fig. S1A-C).