CD5 and acute lymphoblastic leukemia: For instance, CD3 is the lineage-specific marker for T cell lympho-proliferations; physiologically it helps in signal transduction.7 The pan T-cell antigens i-e CD5 and CD7 are markers specific to both mature and immature T-cells and help in immune regulation.7 CD 10 or CALLA is a zinc dependent metalloprotease and is helpful in diagnosis of childhood ALL on cycling cells with propensity to apoptosis.