The major challenge in minimal residual disease (MRD) detection is the antigen modulation in post treated samples restraining the use of diagnostic immunophenotypic (IP) signature of leukemic blasts for MRD detection. The IP expression of 10 antigens in 167 children diagnosed as B-acute lymphoblastic leukemia (B-ALL) in comparison to hematogones and the extent of immunomodulation in 60 post treated MRD positive cases were studied. Upregulation was the predictable shift noted in antigens like CD73, CD86, CD19, CD20 and CD45 which was statistically significant for all except CD45. Downregulation was the predictable shift noted in antigens like CD10, CD38, CD58 and CD34 and was statistically significant in all. CD123 showed no significant trend. This immunomodulation in B-ALL results in aberrant expression of antigens during follow-up compared to the diagnostic phenotypic pattern. Hence it is necessary to be aware of the immunomodulations of antigens used in primary diagnosis to avoid being misled during MRD analysis.
Keywords: Precursor B-lineage; acute lymphoblastic leukemia; immunomodulation; immunophenotyping; minimal residual disease.