Frequent gene expression of granulocyte colony-stimulating factor (G-CSF) receptor in CD7+ surface CD3- acute...

Gene expression of various cytokine receptors in CD7+ acute lymphoblastic leukemia (ALL) cells in relation to responsiveness to these cytokines was examined by reverse transcription polymerase chain reaction and Northern blot studies. Leukemic cells from all of seven CD7+ ALL patients examined fulfilled the criteria for ALL according to the FAB classification; surface CD3 was absent in all of these patients, while cytoplasmic CD3 and/or CD3 epsilon mRNA were found in all of them. Samples from six of the seven patients at initial disease expressed the granulocyte colony-stimulating factor receptor (G-CSFR) gene. Leukemic cells with G-CSFR transcripts from one patient at initial disease showed growth response to G-CSF in vitro, and those from two other patients became responsive to G-CSF at relapse. Neither in vitro nor in vivo myeloid differentiation was observed in any samples that responded to G-CSF. Interleukin 3R alpha (IL-3R alpha) gene was expressed in samples from one patient at initial disease and from two patients at relapse. GM-CSFR beta gene mRNA was detected in two patients with IL-3R alpha mRNA. Our results show that the leukemic cells in these CD7+ ALL patients frequently expressed G-CSFR as a functional property, thus calling attention to the appropriate clinical application of G-CSF for ALL patients.