Correlation of expression of aberrant immunophenotypic markers in T-ALL with its morphology: A pilot study

Aberrant expression of immunophenotypic markers is commonly found in patients of acute leukemia. T-ALL also shows aberrant markers such as CD13, CD33, CD117, CD10, and CD79a. Morphologically, T-ALL has been categorized into L1, L2, and L3 subtypes. Till now, no study has been done to correlate these markers with morphological features of T-ALL. This study aimed to correlate the expression of aberrant immunophenotypic markers with morphology in T-ALL.

All the cases of T-ALL diagnosed by flow cytometry over a period of 2½ year were taken out from the records of Hematology Section of Department of Pathology of University College of Medical Science and Guru Teg Bahadur Hospital and Max Hospital, Saket. Their peripheral blood smear was screened to correlate the morphology of blasts with the expression of aberrant markers.

A total of 40 cases of T-ALL were identified during 2½ year period of our study. Morphological correlation was available for 23 cases. Aberrant expression of CD10 was present in 6 (35.3%) cases, CD79a in 9 (47.36%) cases, CD117 in 5 (42.28%) cases and myeloid antigen CD33 in 5 (38.46%) cases. CD117 and CD33-positive cases showed L2 morphology with the presence of convolutions, while cases with expression of CD79a had L1 morphology with absent-slight convolutions. CD10-positive cases had L1/L2 morphology with absent occasionally present convolutions.

There seems to be an association of aberrant markers with L1 and L2 morphology. However, this needs to be tested for statistical significance on a larger sample size.