Survival and reactivations in RO+ MS-LCH. RO+ patients in LCH-I, LCH-II, and LCH-III were analyzed, considering only the identically matched (ie, RO+) LCH-I and LCH-II patients. Both RO+ arms (A and B) of LCH-III are included in the curves shown for LCH-III. RO– patients younger than 2 years (age alone no longer a risk factor) were not included. (A) Survival: LCH-III vs LCH-II, LCH-III vs LCH-I, and LCH-III vs combined LCH-I and LCH-II; all are significant at P < .001. (B) Reactivations after NAD: LCH-III vs LCH-II, P < .004; LCH-III vs LCH-I, P < .005; and LCH-III vs combined LCH-I and LCH-II, P < .001.