Splenomegaly

To learn if giving ruxolitinib and busulfan before a stem cell transplant can help to reduce spleen size and help the transplant to succeed.

This phase II trial studies how well ruxolitinib works in treating patients with hypereosinophilic syndrome or primary eosinophilic disorders.

The goal of this clinical trial is to optimise and facilitate screening for Acid SphingoMyelinase Deficiency (ASMD) disease, by evaluating acid sphingomyelinase activity and, where appropriate, LysoSM levels in a cohort of 200 participants with diffuse interstitial lund disease (ILD) at risk of developing ASMD disease. ILD is common in the general population, so in order to limit the number of differential diagnoses, the population to be studied will be restricted to participants aged between 15 years and 3 months and 60 years, with ILD plus ground-glass opacities on chest CT scan certified by a pulmonologist/radiologist or internist, AND splenomegaly or splenectomy, and/or thrombocytopenia, and/or low HDL cholesterol, and/or parental consanguinity which increase the sensitivity of ASMD screening. In this clinical trail, two procedures are added, participants will be asked for : * a blood sample to measure the acid sphingomyelinase enzyme activity and LysoSM, if required. * a follow-up visit at 6 months