Acute Lymphocytic Leukemia

Acute Lymphocytic Leukemia



Jadallah A. Ebrahim, Abanoub A. Tanious, Ahmed G.Mirgani, Esmail T.Almahi, Khabbab I. Elshareef, Eltayeb A. Abd Elgadir contributed equally to this work, Department of Hematology and Immune-haematology, Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan.


Acute lymphoblastic leukemia (ALL) is the most common type of neoplastic disorder diagnosed in childhood. It is the cause of one third of all pediatric malignancies. Immunophenotyping has become extremely important not only in diagnosis and sub classification of T-ALL but also in the detection of the minimal residual disease. Immunophynotypic pattern of T-ALL in Sudanese patients have not been addressed before


This study was designed to characterize immunophenotypic patterns of T-ALL in Sudanese patients. Multiparameter flow cytometry and CD45/SSC gating were used to analyze the surface and cytoplasmic antigen expressions in 50 cases of T-ALL during the period January 2017 to April 2017 at Flowcytometry laboratory-Khartoum, Sudan. The following antigens: CD45, HLA-DR, CD34, CD1a, CD2, surface and cytoplasmic CD3, CD4, CD5, CD7 and CD8 were used.


The study was conducted at Flowcytometry laboratory of Khartoum, Sudan, during a period of four months from January 2017 to April 2017. A total of 50 acute lymphoid leukemia (T-ALL) cases were immunophenotyped using 4 colors flowcytometer. The analyzed samples were either of peripheral blood (PB) or bone marrow aspirate (BMA) according to availability and presence of blast cells. Morphological examinations to all blood or B.M. slide films were first done followed by cytochemical stains.

Venous blood sample: For each patient a 3 ml of venous blood sample was collected in E.D.T.A and  counted by hematology analyzer – SYSMEX KX-21). Bone marrow aspiration: 2 ml of bone marrow aspiration was collected in E.D.T.A. Each sample was stained by monoclonal antibodies for the following antigens: CD1a, CD2, cCD3, sCD3, CD4, CD5, CD7, CD8, HLA-DR, CD45, CD34 (Immunostep-SL, Spain) Then analyzed by the flowcytometer (EPICS XL-MCL 4 colors Beckman Coulter flowcytometer, Maiami, FL, USA).

the cut off point between negative and positive scale for every marker is ≥ 30%.


 According to the demographic data of the study, age of patients ranged from 1 to 60 years (mean: 14.38 years) and the predominant age group was (6-16) years, which approximately comprised 58% of cases. There were 36 (72%) males and 14 (28%) females

Findings of Complete Blood Cells count (CBC) were as follows:

Hemoglobin (HB): The mean of Hb level for patients of T-ALL was (9.2g/dl).

TWBC: mean TWBC was 221.1×10⁹/ml among subtypes of T-ALL and the lowest mean was 6.8×10⁹/ml that presented by the pro T-ALL subtype.

Platelets: The highest mean was 252 X10⁹/ml, found in pro T-ALL and the lowest mean was 28.6X10⁹/ml showed by mature T-ALL subtype

Immunophenotyping: All T-ALL blasts expressed CD45 with no significant differences between different T-ALL subtypes, whereas, CD34 showed different expressions.

cCD3 (cytoplasmic) and sCD3 (surface) were studied among the blast population, having mean positivity of 77.7% and 19.2%, respectively in all T-ALL subtypes, collectively. CD1a was found to have higher positivity among cortical T-ALL, with mean positivity of 81.7%. No significant correlation between gender, and age to T-ALL subtype. CD5 and CD2 were mostly expressed in pre T-ALL with mean positivity of (92.8%) and (55.6%), respectively. CD5 and CD2 were not expressed in pro T-ALL and have a mean negativity of (20.1%), (7.3%); respectively. sCD3 was highly expressed in cases of mature T-ALL with mean (87.7%). Interestingly, our results revealed that cortical T-ALL is the most predominant subtype among the Sudanese patients (68%).

The mean percentage of immunophenotyping markers of T-ALL subtypes. Mean %  


CD1a CD2 sCD3 cCD3 CD4 CD5 CD7 CD8  
Pro. T cell 0.80 7.35 3.97 87.40 1.34 20.10 91.20 2.09  
Cortical 81.72 56.77 19.30 77.80 56.33 90.98 81.50 32.10  
Pre. T cell 15.82 55.63 21.79 80.88 17.28 92.89 67.28 10.21  
Mature T. cell 8.80 27.59 87.73 86.53 34.69 63.85 59.00 12.15











Gender distribution among the cases and Sub Diagnosis subtypes (P value = 3.74).* Sub Diagnosis




M                     F                Total








Pro. T cell Count

% of Total









Cortical Count

% of Total









Pre T cell Count

% of Total









Mature T cell Count

% of Total







Total Count

% of Total










Flowcytometry is a powerful tool for diagnosis and classification of T-ALL, as proved by the current study which enabled us to subclassify T-ALL into proT-ALL, preT-ALL, cortical T-ALL and mature T-ALL. Our results were comparable with that of other series,cortical T-ALL is the most predominant subtype among the Sudanese patients. In summary, we provide an immunophenotypic characterization of T-ALL for Sudanese patients with leukemia. Accordingly, Flowcytometry will be applied as an important tool to diagnose T- ALL. Further studies correlating together the flowcytometric, and genetic findings are recommended.


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