Hypocellular myelodysplastic syndromes (h-MDS): from clinical description to immunological characterization in the Italian multi-center experience

Taking advantage of the National Registry of the Italian Foundation of MDS (FISiM), we evaluated clinical features, overall survival (OS) and treatment of h-MDS in comparison with n-MDS. A cohort of 1945 MDS patients, enrolled in the FISiM registry, was included in the study. Patients were selected based on the availability of bone trephine biopsy evaluation and complete clinical annotations. Diagnosis of h-MDS was assumed for BM cellularity ≤30% and the prognostic stratification of patients was defined according to the Revised International Prognostic Scoring System (IPSS-R) [9]. Within the main cohort, 336/1945 (17%) patients were recognized as h-MDS and 1609/1945 (83%) as n-MDS. The age of patients ranged between 18 to 106 years, with a global M/F ratio of 1.56. According to BM cellularity, median age was 75 and 74 years in the h-MDS and n-MDS groups, respectively; the M/F ratio was 1.14 in h-MDS and 1.67 in n-MDS (p < 0.01). The stratification of patients into IPSS-R risk categories was similar between h-MDS and n-MDS (Fig. 1A). An IPSS-R score of 3.5 was used to stratify patients into two main groups: low-risk IPSS-R (LR, score ≤3.5) and high-risk IPSS-R (HR, score >3.5). Accordingly, 271/336 (81%) h-MDS were placed in the LR and 65/336 (19%) in the HR categories; similarly, 1176/1609 (73%) of n-MDS were included in the LR, while 433/1609 (27%) in the HR groups.