Clonality analysis of childhood ALL in remission: no evidence of clonal hematopoiesis.

We studied 98 female patients in remission (2-240 months) from childhood ALL to determine the clonality status of their hematopoiesis. Thirty-one (31.6%) were heterozygous at the PGK locus for the BstX1 endonuclease restriction site, permitting X-linked clonality assays to be performed. Two patients were in relapse at the time of study and were excluded. We used the PGK-PCR clonality assay (PPCA) to analyze DNA from PMN and mononuclear cells of the remaining 29 female patients. All (29/29) patients demonstrated polyclonal hematopoiesis. These data show that remission from childhood ALL involves reestablishment of polyclonally derived hematopoiesis in all patients studied.