Cysts were mainly found in the LCH patients (n = 6) (Fig. 3B1, B2), and also in the patients with CTD, vasculitis, DAH with no proof of systemic disease, COPA syndrome, CVID, CGD, STAT3 mutation, and surfactant dysfunction disorders. This evidence concerns the gene STAT3 and autoimmune interstitial lung disease-arthritis syndrome.