Immunophenotypic profile of acute leukemia: critical analysis and insights gained at a tertiary care center in India.

Background: To analyze the spectrum of various types and subtypes of acute leukemia.

Methods: Two thousand five hundred and eleven consecutive new referral cases of acute leukemia (AL) were evaluated based on WHO classification.

Results: It included 1,471 cases (58%) of acute lymphoblastic leukemia (ALL), 964 cases (38%) of acute myeloid leukemia (AML), 45 cases (1.8%) of chronic myelogenous leukemia in blast crisis (CMLBC), 37 cases (1.5%) of biphenotypic acute leukemia (BAL), 1 case of Triphenotypic AL, and 2 cases of acute undifferentiated leukemia (AUL). Common subtypes of ALL were B-cell ALL (76%), which comprised of intermediate stage/CALLA positive (73%), early precursor/proBALL (3%). T-cell ALL constituted 24% (351 cases) of ALL. Common subtypes of AML included AMLM2 (27%), AMLM5 (15%), AMLM0 (12%), AMLM1 (12%), APML (11%), and AML t(8;21) (9%). CMLBC was commonly of myeloid blast crisis subtype (40 cases).

Conclusion: B-cell ALL was the commonest subtype in children and AML in adults. Overall incidence of AML in adults was low (53% only). CD13 was most sensitive and CD117 most specific for determining myeloid lineage. A minimal primary panel of nine antibodies consisting of three myeloid markers (CD13, CD33, and CD117), B-cell lymphoid marker (CD19), T-cell marker (CD7), with CD45, CD10, CD34, and HLADR could assign lineage to 92% of AL. Cytogenetics findings lead to a change in the diagnostic subtype of myeloid malignancy in 38 (1.5%) cases.