Aberrant phenotypes in childhood and adult acute leukemia and its association with adverse prognostic factors and clinical outcome

Occurrence of aberrant phenotypes in childhood and adult acute leukemia (AL) differs considerably in independent studies and their association with prognostic factors is still controversial. In the present study, 214 patients with AL (106 children and 108 adults) were evaluated for the aberrant expression of CD33 in ALL (B cell and T cell) and CD3, CD5, CD7, and CD19 in AML. In B-ALL, aberrant expression of CD33 was found in 39 and 23% cases of adult and children, respectively. In T-ALL, CD33 was seen in 33% cases of adults while in children CD33 was not observed. In AML, aberrant expression of CD19 was expressed in 52 and 32% while CD7 was expressed in 14 and 15% cases of childhood and adult AML, respectively. Among FAB subtypes, aberrant expression of CD19 and CD7 was more commonly seen in M5 subtype. One adult patient (AML-M5) showed expression of CD3, CD5, and CD19. In summary, aberrant phenotype was commonly seen in adults than childhood B-ALL while in AML, aberrant phenotype was more common in children than adults. CD19 was most commonly expressed antigen followed by CD7 in both childhood and adult AML. Interestingly, aberrant phenotype was not found in childhood T-ALL; however, it was seen in 33% cases of adults. We did not find any association of aberrant phenotype with adverse prognosis factors, CD34 marker, and clinical outcome except the absence of auer rod which was found to be significantly associated with aberrant phenotype of childhood AML (P = 0.01).