The two subtypes of CLAD, restrictive allograft syndrome (RAS) and bronchiolitis obliterans syndrome (BOS), exhibited distinct expression patterns of alarmins including S100A8, S100A9, S100A8/A9, S100A12, S100P, HMGB1 (high mobility group box-1), and soluble RAGE suggesting different biologic profiles of CLAD subtypes. The gene discussed is HMGB1; the disease is bronchiolitis obliterans syndrome.