Myeloproliferative neoplasms (MPNs) are a group of clonal hematopoietic disorders which categorized according to the World Health Organization (WHO) into Philadelphia Chromosome positive (Ph +ve) including chronic myeloid leukemia (CML) and Philadelphia Chromosome negative (Ph -ve) like essential thrombocythemia (ET), polycythaemia vera (PV), and primary myelofibrosis (PMF) .

the aim of the study is to Detection of leukocyte cell population data in patients with MPNs and Relation between leukocyte cell population and patients' clinical status.

MPNs are characterized by sepsis, thrombosis, myelofibrosis and leukemic transformation as critical complications of the disease. Most recently, the MPNs have been described as "Inflammatory Diseases" because the chronic inflammation being identified as a key factor in the development and progression of the disease . It is characterized by persistent activation of immune cells, elevated leukocyte and platelet counts, release of various mediators, DNA and tissue damage . Consequently. when neutrophils are activated by different stimuli, they undergo degranulation and release neutrophil extracellular traps (NETs) and microparticles, leading to thrombosis in MPNs by blocking blood vessels . Monocyte and its distribution are also a simple marker of activation useful for early sepsis detection .

The leukocyte cell population data (CPD) are parameters used to provide quantitative information on the morphological and functional characteristics of leukocytes. CPD assessment involves measuring neutrophil and monocyte forward scatter (Z axis) for cell size and side scatter (X axis) for internal complexity. Additionally, fluorescence intensity (Y axis) for DNA/RNA content and cell population variability (dispersion width) can also be evaluated.

Therefore, assessing of these parameters in the context of sepsis and thrombosis as a complication of MPNs helps to understand how these conditions interact at the cellular level and provides insights into morphological changes and abnormal leukocyte distribution for early detection and management .

Inclusion Criteria:

• Patients with MPNs according to the recent WHO classification.

Exclusion Criteria:

• Patients with other types of myeloid neoplasms and/or not fulfil the WHO criteria for MPNs diagnosis.

- Patients with MPNs according to the recent WHO classification.