Hematological and ImmunophenotypicCharacteristics of Acute Myeloid Leukemia inYemeni Patients

Background: Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by clonal proliferation of immature myeloid cells, resulting in impaired normal hematopoiesis. Data on the hematological and immunophenotypic characteristics of AML in Yemeni patients remain limited.Objectives: This study aimed to describe the demographic, hematological, morphological subtypes, and immunophenotypic features of newly diagnosed AML among Yemeni patients.Methods: A descriptive cross-sectional study was conducted on 50 newly diagnosed AML patients recruited from three oncology centers in Sana’a and Ibb, Yemen, between Aug. 2024 and Dec. 2025. Demographic and laboratory data were collected at diagnosis. Complete blood count, peripheral blood smear examination, bone marrow aspiration wherever available and flow cytometric immunophenotyping were performed. AML subtypes were classified according to the French-American-British (FAB) system. Statistical analysis was carried out using SPSS version 26, with sig. at p<0.05.Results: The mean age of patients was 37.22±17.48 years, with a slight male predominance (56%). At presentation, the mean hemoglobin level was 8.62±1.62 g/dL, white blood cell count (WBCs) was 80.34±39.94×109/L, platelet count was 77.28±35.00×109/L, and peripheral blast percentage was 60.44±21.05%. Anemia, leukocytosis, and thrombocytopenia were observed in 94%, 98%, and 96% of patients, respectively. FAB classification showed that AML-M2 was the most frequent subtype (28.0%). Immunophenotypic analysis demonstrated highexpression of CD33 (96%), CD13 (86%), and CD117 (82%), while aberrant lymphoid marker expression was infrequent. A significant negative correlation was observed between hemoglobin and WBC count (r = −0.289, p = 0.042), and a significant positive correlation between hemoglobin and platelet count (r = 0.306, p = 0.031). Bone marrow and peripheral blood blast percentage differed significantly among FAB subtypes (p < 0.001).Conclusion: Yemeni patients with AML have a high leukemic blast percentage and present at a younger age. The most common subtype is AML-M2, and CD33, CD13, and CD117 were the predominant immunophenotypic markers. These findings highlight the diagnostic value of flow cytometry and the need for broader molecular and cytogenetic characterization of AML in Yemen.