Introduction: Including of proliferative parameters in the routine clinical flow-cytometry (FC) workup may be important for better evaluation of prognosis and risk assessment in patients with myelodysplastic syndromes (MDS). However, supportive data are still contradicting. Aim: To assess the levels of FC based proliferative parameters in patients with MDS using propidium Iodide, and to study their correlation with risk assessment and the incidences of CD34+ blasts and CD16- and CD16+ granulocytes. Methods: Data was retrospectively collected and analysed from 40 specimens of bone marrow (BM) aspiration of MDS patients, 14 specimens of hypocellular BM with no evidence of malignancy, and 16 specimens of reactive BM as determined by pathological examination. IPSS-R scores were calculated for MDS patients then divided to high-risk (IPSS-R score >4.5) and low-risk (IPSS-R score <3). The levels of proliferative parameters and their correlation with incidence of CD34+ blasts and CD16- and CD16+ granulocytes were compared between high and low risk MDS patients. Results: MDS and reactive BM specimens showed similar whole sample S-phase percentage that was significantly higher than hypocellular BM specimens. As compared to MDS, reactive BM show a greater S-phase percentage in the erythroid fraction. In MDS, the whole sample S-phase percentage was significantly high in a subset of high-risk patients. Increased S-phase percentage in these patients was attributed to high S-phase percentage in granulocytes and monocytes. S-phase percentage correlated with the level of CD34+ blasts in the low-risk group but not in the high-risk group. In contrast to CD34+ blasts, the S-phase percentage correlated with the level of CD16- granulocytes in the high-risk group but not in the low-risk group. Conclusions: Our observations confirm the association of increased proliferative parameters and adverse prognosis in MDS, and suggest differential proliferation pattern of CD34+ and CD16- granulocytes in low and high-risk MDS patients.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics committee/IRB of the Galilee Medical Center gave ethical approval for this work

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors