Immunophenotypic changes between diagnosis and relapse in childhood acute lymphoblastic leukemia

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Childhood acute lymphoblastic leukemia (ALL) is a heterogeneous disease.
• Understanding phenotypic changes at relapse is crucial for treatment and prognosis.
• Previous studies have indicated potential shifts in leukemia cell markers during relapse.

Purpose of the Study:

• To investigate morphological and immunophenotypic changes in childhood ALL at relapse compared to diagnosis.
• To identify specific marker shifts and their implications for leukemia classification.
• To evaluate the correlation between morphological and immunophenotypic alterations.

Main Methods:

• Morphological and immunophenotypic analysis of 40 childhood ALL cases (32 precursor B-ALL, 8 T-ALL) at diagnosis and relapse.
• Expression patterns of non-lineage, B-lineage, T-lineage, and myeloid markers were assessed.
• Double labeling and marker shift definitions (> or = 50% change) were employed.

Main Results:

• Morphological differences were observed in 34% of precursor B-ALL and 14% of T-ALL.
• Immunophenotypic shifts occurred in 72% of precursor B-ALL and 75% of T-ALL, involving minor marker changes.
• Intra-lineage shifts occurred in 10% of precursor B-ALL, and inter-lineage shifts in 5%, with some cases reclassified as acute non-lymphocytic leukemia.

Conclusions:

• Immunophenotypic shifts are common at relapse in childhood ALL, affecting both precursor B-ALL and T-ALL.
• These shifts can lead to intra-lineage or inter-lineage changes, impacting diagnostic classification.
• Monitoring minimal residual disease in ALL should utilize multiple marker combinations and potentially molecular techniques.