Those authors showed high serum IL-17A levels in LCH and argued that serum IL-17A supported healthy monocyte-derived dendritic cell (DC) fusion capacities in vitro, rather than serum IL-17A levels, which is more correlated with LCH severity (i.e., the IL-17A paradox) [36]. Here, IL17A is linked to Langerhans cell histiocytosis.