Introduction: Flow cytometric immunophenotyping remains an indispensable tool for the diagnosis, classification and monitoring of acute leukaemias. Occurrence of aberrant phenotype has been reported in acute leukaemia with varying frequency. Aberrant expression has relevance to prognosis and can help in identification of minimal residual disease on follow up.

Aims and Objectives: To study the morphologic and immunophenotypic profile of acute leukaemia and to determine the incidence of various subtypes. This study also aims to find out the frequency of cross lineage antigen expression in acute leukaemias.

Methods and Material: All consecutively diagnosed cases of acute leukaemias by flow cytometry during July 2017 to June 2018 were retrospectively reviewed and analysed.

Results: Over a period of one year, 510 individuals were diagnosed with acute leukaemia. Among 510 cases, 53% (270) were acute myeloid leukaemia (AML), 45% (230) were acute lymphoblastic leukaemia (ALL) and 2% (10) were mixed phenotypic acute leukaemia (MPAL). Aberrant lymphoid expression was seen in 34% of AML and CD 7 was the frequently expressed marker. Out of 230 cases of ALL, 156(68%) were B-ALL and 74(32%) were T-ALL. CD 13 was the most common aberrant myeloid antigen expressed in ALL followed by CD 33.   

Conclusion: AML accounted for 53% of all acute leukaemias, commonest subtype being AML-M4. Aberrant lymphoid expression was seen in 34%  of AML and CD 7 was the frequently expressed marker. CD 13 was the most common aberrant myeloid antigen in ALL. Recently recognized entity, Early T- Precursor (ETP) lymphoblastic leukaemias accounted for 20% of all T-ALL.

Keywords: Acute leukaemia, Immunophenotyping, Acute lymphoblastic leukaemia, Acute myeloid leukaemia.

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Dr Rekha A Nair

Director, Regional Cancer Center, Thiruvanthapuram 695011, Kerala, India